Scotland to Adopt Passivhaus Standard for new Houses

 

Linn Way, Garelochhead - a Passivhaus Development of 10 homes by Argyll Community Housing Association (ACHA) 

On 15th December 2022, Patrick Harvie, Minister for Zero Carbon Buildings, Active Travel and Tenant's Rights (there's a job title for you), wrote to Alex Rowley, a member of the Scottish Parliament to inform him that his campaign for new homes in Scotland to be built to Passivhaus standard would become law.

Back in November, Rowley had  introduced a Member's bill to the Scottish Parliament, the "Proposed Domestic Building Environmental Standards (Scotland) Bill" – which would introduce new minimum environmental design standards for all new-build housing to meet a Scottish equivalent to the Passivhaus standard.

The bill followed on from a public consultation which Rowley had organised earlier in the year.  

The consultation received 629 responses which included submissions from  Cala Group Ltd,  Barratt Developments PLC, the Scottish Federation of Housing Associations and The Royal Incorporation of Architects in Scotland - people were taking this seriously!

Having garnered the support of more than 18 MSPs from at least two political parties, the Bill was due to be debated in the Scottish Parliament.  Instead the Scottish Government choose to avoid the debate by announcing that it intended to give the Bill effect through subordinate legislation within two years.

"I hereby state that the Scottish Government will make subordinate legislation within two years, to introduce new minimum environmental design standards for all new-build housing to meet a Scottish equivalent to the Passivhaus standard"  Patrick Harvie MSP, 15 December 2022

So where does this leave the future direction of Scottish Building Regulations?

The Passivhaus standard is remarkably simple to summarise

1. Maximum space heating demand cannot exceed 15kWh per square metre of net living space per year, or 10W/m2 of peak demand

2. The Primary Energy Demand (total energy used for all domestic applications (heating, hot water and domestic electricity) must be less than 60kWh/m2 per year.

3. Airtightness cannot exceed 0.6 air changes per hour at 50 Pascals pressure.

A key difference between the Passivhaus standard and the Scottish (and rest of UK) building regulations is that Passivhaus is absolute while Building Regulations are relative.  

UK building regulations work by taking a house shape you want to build, calculating the annual energy use if that house was built following an approved specification (the notional house).  The specification for the house you build cannot be worse than the notional house.  

You can read more about how UK building regulations for energy work in this earlier post.

Buildings that minimise the ratio of their surface area to their inside volume are intrinsically more energy efficient than buildings with a high surface area to volume ratio.  Simple rectangles outperform complicated (but architecturally appealing) building forms with cross wings, porches, bay windows, dormer windows and the like.  Large buildings out perform smaller buildings on this measure too.  Linked buildings (terraced, semi-detached) outperform individual buildings.

Credit: BRE Passivhaus Designers Guide

Passivhaus rewards efficient building form because it is concerned with the absolute energy use, UK building regulations ignores building form because it compares the performance of that house design with a notional house of the same shape.

In terms of the resulting specification that might achieve the standard, the Passivhaus Institute estimates that for most cool-temperate climates : 

Walls, floors, roofs: A heat transfer coefficient (U-value) of 0.15 W/(m²K)

Windows:  U-value of 0.80 W/(m²K) 

The notional house specification for Scottish Building Regulations 2022 uses a U value of 0.15 for walls, 0.12 for floor, 0.09 for roofs and 1.2 for windows.   So with the exception of windows, Scotland will be building homes that already largely meet or exceed the specification, so long as building shape and orientation does not require higher levels.

Air permeability is 5m3/h.m2 in Scottish Building regulations notional house.  Taking a storey height of 3m, this translates into 1.67 air changes/hour.  To get to 0.6 air changes/hour will require a big improvement to an area that has proven to be challenging in the past, especially when building in volume with traditional methods rather than off-site manufacture.

The final big change is  that Scottish (and UK) Building Regulations only consider energy used for space heating, domestic hot water, and electricity for lights and services (pumps and controls).  It ignores the main part of electricity used in the house to run appliances and plug-in devices - a weakness that becomes increasingly noticeable as homes become better insulated.

By contrast the Primary Energy Demand requirement in the Passivhaus standard considers all the energy use in the property with allowances for electricity consumption by residents using appliances and electronic devices.

It is worth noting that energy generated by Photovoltaic (PV) systems may not be counted against the Primary Energy target in the Passivhaus calculator (called PHPP). This is a deliberate implemented to prevent poor standards of energy efficiency being offset by the use of renewable energy.  As emerging technology maximises the use of solar generated electricity (for example solar diverters and battery storage), this is looking increasingly anachronistic.

The Passivhaus Institut is moving towards including PV  generation in Passivhaus certification. This will be in the form of new classes "Passivhaus Plus" and "Passivhaus Premium". These standards require the same fabric standard as any other Passivhaus but higher reductions in the primary energy demand compared with the existing Passivhaus standard, normally achieved using on-site generation.

This decision by the Scottish Government has really has the potential to overturn an orthodoxy that for years has based energy efficiency standards for homes on the government's own calculation - the Standard Assessment Protocol (SAP), which has been the overarching mechanism to demonstrate compliance with building regulations on energy for decades.  

How revolutionary this change turns out to be, well, time will tell - after all the Scottish government only committed to a 'Scottish version of Passivhaus' which could be as limited as a new version of SAP with exceptionally high U values and airtightness in the notional house.  Alternatively if the founding principles of Passivhaus are followed, it could turn out to be a radical shift in the way the building regulations are delivered in the UK.

Options, Options - The Building Regulations Review & the Notional House

I have read commentary in recent weeks on the 2020 Building Regulations Review that suggests an alarming level of ignorance about the way the building regulations work.  It would be a real shame if the organisations behind these comments were to base their response to the consultation on such a fundamental misunderstanding.

The government consultation is proposing two options for new 2020 building regulations - one that it estimates would deliver a 20% reduction in carbon emissions compared to current regulations and another expected to deliver a 30% reduction.

So you would expect that groups interested in energy efficiency would support the second option - producing a 30% reduction.  But no, some seem to prefer Option 1, because they wrongly think it will result in homes with higher levels of thermal insulation.

It won't.

Let me explain.

The Building Regulations for Energy - How it Works

To comply with the Building Regulations for energy efficiency, housebuilders must use a calculation called the Standard Assessment Procedure (SAP) to demonstrate that the house they plan to build will meet requirements to limit carbon emissions and (new in the upcoming version of building regulations) primary energy consumption and affordable energy bills.

Related article: What is Primary Energy?

Focusing on carbon emissions and primary energy, the way the calculation works is as follows.  (See also the figure above).

1. You decide the geometry of the house you want to build (it's dimensions, shape and openings - number and size of windows and doors)

2. You calculate a Target Emissions Rate (TER) and Target Primary Energy (TPE) for a "Notional House".  The Notional House is the same shape as the actual house you want to build but has a technical specification based on Reference Values defined in Appendix R of SAP.  The Reference Values include insulation performance (U-values) for all the building elements (walls, windows, roof, floor), a maximum allowable amount of openings, as well as air change rates, a heating system and renewable technologies.

3. You then choose the technical specification you actually want to build the house to.  These can differ from the Reference Values - you are free to choose a different heating system, to build to higher or lower insulation levels, to aim for higher or lower air-tightness and whether to include more or less renewable or energy saving measures.  The only constraint is that insulation levels must be higher than so-called backstop values, which are also defined in the regulations.  You calculate the Dwelling Emission Rate (DER) and Dwelling Primary Energy (DPE) based on this house design.

4. So long as the carbon emissions and primary energy for the actual house are lower than the target figures generated by the Notional House, you're good to go, the design is compliant.

This elegant system defines a level of performance for the energy efficiency of new homes while giving developers a free hand in how they want to build.

Option 1 in the consultation sets the Reference Values for the notional house to have highly insulated walls, floor roof  and openings.  The Reference Values given for Option 2 come with slightly lower insulation levels, but add in solar PV and waste water heat recovery to the specification, resulting in lower overall energy use and carbon emissions than Option 1.

Just because Option 1 has higher insulation in the reference values it does not mean that houses will be built with this level of insulation.  As mentioned earlier, developers have complete freedom to choose a specification so long as it meets the target emissions and primary energy levels.  If it is a lower cost option, they are just as likely to reduce the insulation levels and add solar PV to meet Option 1.

If you are interested in lobbying for a 'Fabric First' approach, then you should focus on arguing for more ambitious backstop values for insulation and airtightness, but please don't argue for Option 1 Reference Values.  Option 2 will deliver higher-performing homes and will force housebuilders to push energy efficiency further and faster.  It will also likely result in higher levels of insulation in as-built homes.



 

The Future Homes Standard Consultation

Where next for Building Regulations?

In the week where Extinction Rebellion activists were arrested for hosing the Treasury in 'blood' in protest at the lack of progress on tackling a climate emergency, the consultation on the Future Homes Standard came out.  There's talk of solar panels for all new homes - so let's take a look under the hood of the consultation.

The consultation itself consists of two main parts - consideration of the Future Homes Standard due to come into force in 2025 which is intended to deliver "world-leading levels of energy efficiency" for new homes and  an update to the Building Regulations Part L (energy efficiency) and Part F (ventilation) in 2020 to provide a "meaningful but achievable" uplift in energy efficiency as a first step towards the 2025 vision.

There's also a raft of supporting documentation

The Standard Assessment Procedure (SAP) calculation version 10.1
An Impact Assessment, which includes details of cost assumptions
Approved Documents L and F 

2020 Part L - a Stepping Stone to Future Homes 2025

There's a lot to talk about here.  This is no 'tweak' but a significant revision, at least in part forced by the significant changes to the carbon intensity of grid electricity, but also by the Grand Challenge Mission for Buildings, announced by Theresa May about a year ago.

1. Primary Energy Use is the new Gold Standard

Until today, Part L has always used carbon dioxide emissions as its measure of compliance with regulations.  Buildings had to achieve a certain Dwelling Emissions Rate (DER) in kgCO2/m2.

DCLG has rightly concluded that as the electricity provided by the grid comes with a lower and lower carbon intensity, developers could switch to electric heating and hit a carbon target without improving the energy efficiency of buildings.  If energy efficiency of buildings is not improved, then decarbonising the grid becomes more challenging and costly.  So a new measure is required and primary energy, which has the benefit of aligning UK regulations with the measures chosen in the EU Energy Performance of Buildings Directive, is added as a new metric.

(See this article on the rapid progress made in decarbonising the grid.)

The latest revision to the government's Standard Assessment Procedure (SAP) version 10.1 has been published alongside the consultation.  This is the calculation used to demonstrate a house complies with the building regulations.  In this version of SAP the carbon intensity of electricity is set to 136gCO2/kWh, a projection of the average from 2020-2025, and a massive reduction from the value of 519gCO2/kWh in the current version of SAP 2012.  Electricity now produces less than 65% of the carbon emissions of mains gas (which is at 210gCO2/kWh).

By contrast, the primary energy content of a unit of electricity is 1.501 compared to gas at 1.130.

This document explains primary energy and how the values were arrived at

Fitting solar PV to a property reduces the grid electricity that is needed by the house, solar PV generation used in the building (self-consumption) reduces both the carbon emissions and primary energy by the same factor as grid electricity.

Electricity sold to grid also reduces both the carbon and primary energy use of the dwelling but it's primary energy factor is only 0.501.

The impact of this is that a unit of electricity generated by PV and used in the building would save 1.501 kWh of primary energy use, but a unit of PV generated electricity exported to the grid would only save 0.501 kWh of primary energy use in the calculation.

Since the benefits of battery storage (SAP Appendix M) and PV diverters (SAP Appendix G4)  have also been added to this update to SAP, the combination of using primary energy as the main regulatory target and the low primary energy factor for PV export has the effect of incentivising measures such as these to use as much PV-generated electricity within the building.

The trouble with this is that

(a) developers prefer combi boilers so there's no hot water cylinder in most new homes for a PV diverter to divert excess electricity into.
(b) batteries are approaching cost effectiveness but are likely to be seen by developers as an additional cost and not a sellable benefit.

We understand that the logic for choosing this value for exported energy is that the exported energy has a primary energy factor of 1.0 (renewable energy), and displaces a unit of energy from being fed into the grid at the grid average of 1.501, so the net benefit to primary energy added to the grid is 0.501.

The solar industry might argue that considering things from the point of view of the building produces a different logic (and after all what we're supposed to be modelling is the energy performance of the building).  The net primary energy consumption of the building is the electricity imported at a primary energy factor of 1.501 less the PV generated electricity exported which should have a primary energy factor of 1.0. 

A minimum carbon emissions requirement is retained in addition to the primary energy requirement as this remains an important consideration for government and there is concern that certain solutions could produce low primary energy figures with high carbon emissions - for example heating oil and coal both have low primary energy but  high associated carbon emissions.

Finally, the current fabric efficiency requirement is dropped to make way for a new householder affordability target, with fabric efficiency now considered adequately protected by tougher minimum heat loss standards for building elements.  As discussed, electricity has low and falling primary energy and carbon emissions factors, and government is concerned that direct electric heating would be a viable option for meeting both the carbon and primary energy targets, but with the side-effect of saddling occupants with too-high energy bills.  To guard against this the new affordability rating is likely to be set at a level that means direct electric heating would only be an option when combined to other measures to reduce electricity bills such as increased thermal insulation, PV panels or battery storage.

2. Uplift of the Minimum Standard

The minimum performance standard is defined by publishing a build specification (insulation levels, heating system, light fittings, microgeneration technologies) to be used by the developer to model a 'notional house'.  The developer then has to design the house they plan to build to produce modelled carbon emissions and primary energy lower than that of the notional house.  It's an elegant way to allow the developer complete freedom in design but control the outcome.

 The consultation proposes two options for the minimum performance standard:

Option 1 - "Future Homes Fabric"

This specification would produce a 20% reduction in CO2 emissions when compared against the specification in current building regulations .  The standard is based on a notional home with improved insulation measures (including triple glazing) plus a gas boiler and waste water heat recovery.

The estimate given in the consultation is that this option adds £2557 to the build cost of a semi-detached house and saves households £59 a year in energy bills.  (Payback 43 years)

Given that by 2025 the Future Homes Standard needs to be at a 75% of the carbon emissions of 2013 regulations, 20% does not seem like a big enough step - it only brings England roughly to the level that  Scotland's developers have been achieving since 2015.  DCLG appears to agree, stating that it's preferred option is Option 2.

Option 2 - "Fabric plus Technology"

In this option, the specification of the notional house is set at a level to produce a 30% reduction in carbon dioxide emissions across the build-mix.  The specification has slightly lower insulation than Option 1 plus waste water heat recovery and a solar PV system.

SAP 10.1 Appendix R outlines the specification for the notional house.  The size of the PV system in kWp for the notional house is 40% of the building foundation area divided by 6.5.  So for example for a typical two-storey semi-detached house of total floor area 85m2, this would be

[40% x (85/2) ] / 6.5 = 2.6kWp (around 9 or 10 panels)

DCLG's modelling estimates that building to this new notional home adds £4847 to the building costs and saves £257 a year in energy bills.  (Payback 19 years).

The costs used in the accompanying impact assessment for solar PV are £1,100 fixed costs plus £800 variable per kWp installed.  This implies the following installed costs:

1kWp  £1,900  £1.90/kWp
2kWp  £2,700  £1.35/kWp
3kWp  £3,500  £1.17/kWp

Solar is a fast-paced technology and it would be unusual if a government consultation were to use up-to-date cost information.  My understanding is that solar installers operating in the new-build sector are typically charging an installed price the range of £1.10-£1.20/kWp for four or five panel systems (1 -1.25 kWp).  So it is likely that the costs of Option 2 are over-stated relative to Option 1.

If the solar industry can provide evidence that costs in Option 2 are over-stated, it will make it easier for government to hold the line on its preferred option.

DCLG reckons that Option 2 might result in developers moving away from gas boilers to air-sourced heat pumps.  A specification based on ASHP alone over-shoots the Option 2 target at a lower cost than the notional house (£3,134), which would allow some relaxation of the fabric for further cost savings.  The experience in Scotland suggests that housebuilders will avoid ASHP for as long as possible because customers neither like nor understand them.

3. Heat Pumps - "Lord Make Me Chaste - but not yet!"

The consultation steps away from banning gas heating in 2020, this change is timetabled for 2025.  However it does impose extra conditions on wet space heating systems to ensure that they are 'future proof'.  In practice this will mean that 'emitters' (normal people call them radiators) will be increased to a size that would work at lower temperature, and so the house would be suitable for later conversion to a heat pump heating system without the cost of replacing all the radiators.

A side effect of this requirement is that increasing the cost and space requirements for wet systems could push developers towards direct electric heating with panel heaters, simple underfloor electric or radiant heat panels.  The removal of the entire cost of the wet heating system would offset a considerable chunk of the costs for the additional measures (PV solar, more insulation) needed to stay within the householder affordability target.  A house without a wet heating system would be low on maintenance and low cost to build, coupled with better insulation plus lower cost PV and battery storage to keep bills down this could become a favoured option for new homes.

4. Transitional Arrangements

This proposed change is likely to cause significant concerns at housebuilding companies.

The current situation is that as new Building Regulations come into force, they apply only to whole developments as new planning applications are lodged with local authority planning offices and work has started on site.

The practical outcome of this rule is that new homes are still being built to versions of building regulations in force many years ago, because:

(a) Developers rush to submit planning applications in the run up to new regulations coming into force, banking large numbers of homes to be built under the old regulations
(b) Large sites of many hundreds of homes are built out over many years, but there is a site-wide application of the regulations.

This was clearly demonstrated by the 2015 Scottish building regulations change, where it is only now (nearly 4 years later) that pretty much all new sites coming forward for tender require solar.

The consultation proposes moving from a site-based application of building regulations to one based on specific buildings.  Large developments spanning many years would have to redesign to meet new building regulations that apply as the building is being built.

Housebuilders will be alarmed by this proposal because all developments still under construction under 2013 regulations will be caught in this net.  The land for these sites would have been bought at a price based on the construction costs expected under those 2013 regulations and the housebuilders will argue that this measure is a retrospective action that will harm their profitability.  How much sympathy there is for the housebuilders having to shoulder the extra costs remains to be seen, when government has been subsidising the housing market through the Help to Buy scheme and the chief executives of some companies have been given bonuses amounting to £10,000 per house built .

 5. Other Stuff

Solar PV on Apartment Blocks

 In the original SAP10, PV on apartment blocks connected to the landlords' supply did not improve the DER of the individual apartment, whereas in SAP 2012 the carbon savings were apportioned across apartments by floor area.  The Solar Trade Association argued that connection to Landlord's supply was often by far the most cost-effective and practical way to install solar on apartment blocks, that the changes would force systems to be split into mini-systems serving each apartment at great cost, and that the carbon savings were real.  It seems that this argument has prevailed as SAP 10.1 has changed the treatment of solar PV in apartment blocks back to as it was in SAP 2012. 

Heat Networks Get a Free Pass

SAP 10 introduced punitive heat losses on district heating networks, based on evidence that large amounts of heat are lost in the underground pipework of these systems (40-50% even for best practice new ones).  It seems that government thinks that heat networks will be an important part of the energy future, and that their drawbacks should be ignored.  So a fudge-factor (they call it a 'technology factor') is applied to buildings that use a heat network.  These are allowed to emit 45% more carbon for heating and 5% more primary energy.

The Government's enthusiasm for heat networks is baffling considering that there is a perfectly good electricity network that loses far lower energy in transmission and is already connected to every single property.  A heat network is not of itself low carbon - it depends what you're doing to make the heat.

The Future Homes Standard - for 2025

The second part of the consultation is some early range-finding questions for the Future Homes Standard due to come into force in 2025.

The government reckons a 70-80% reduction in carbon emissions compared to current housing is possible.  This will be achieved by adding low carbon heating (heat pump or district heating) to the Option 1 fabric proposed in the 2020 regulations, and relying on further decarbonisation of grid electricity to do the rest.  Government is seeking views on whether this is achievable.

Local authorities which have been using planning powers under the Planning and Energy Act 2008 to require developers in their region to build to standards above those of the current building regulations.  This role for local authorities has been crucial for pushing forward on energy efficiency during a period of inaction from Westminster.  The consultation considers whether these powers should be removed alongside the 2020 regulations, the 2025 Future Homes Standard or not at all.

Summary

This change is significant and there's still some modelling to be done to figure out which packages of technology developers are likely to favour, but given the simplicity and popularity of solar it seems unlikely that the technology will not be a big winner from these changes to building regulations.

The Grand Challenge Mission for Buildings

It Can be Done - but not Without Solar

In a speech at Jodrell Bank, Prime Minister Theresa May outlined her government's  Industrial Strategy and set out a range of so-called Grand Challenge Missions .

These missions include:

• Using Artificial Intelligence in the Diagnosis and Treatment of Chronic Diseases
• Meeting the needs of an ageing society
• Reducing Energy Use in Buildings, and
• Zero Emissions Vehicles

The missions aim to bring together government, businesses and organisations across the to develop 'industries of the future'.

According to the government website, for buildings the mission is to :

At least halve the energy use of new buildings by 2030

Heating and powering buildings accounts for 40% of our total energy usage in the UK. By making our buildings more energy efficient and embracing smart technologies, we can cut household energy bills, reduce demand for energy, and boost economic growth while meeting our targets for carbon reduction.

For homes this will mean halving the total use of energy compared to today’s standards for new build. This will include a building’s use of energy for heating and cooling and appliances, but not transport.

The mission also includes a target to reduce the cost of low energy retrofits of existing stock (for example Energiesprong approaches I've already written about), but in this article I'll be taking a look at what it means for new buildings.

Unpacking What The Buildings Mission Means

There's some key phrases in the above announcement, with far-reaching implications.

1. 'use of energy'

Up until now, the energy performance of new homes for Building Regulations has been assessed in terms of carbon dioxide emissions rather than energy. The argument for this has been persuasive - that there are UK carbon budgets to aim for and policies should be directly targeted towards achieving this.

However, as grid electricity has decarbonised rapidly, it has created a significant challenge for this approach. With very low carbon electricity, it would be possible to meet regulations for low carbon emissions in buildings simply by heating electrically and doing the bare minimum on energy efficiency. Clearly, adding many new buildings of low energy efficiency this would make the task of maintaining a low carbon grid that much more difficult.

Secondly, and increasingly, the time of day that you take off electricity from the grid affects the carbon intensity (and price) of your energy. Smart technologies are available that control energy use that has flexibility in its timing (technologies such as heating, running a washing machine, cycling a fridge freezer, charging an electric vehicle or discharging a domestic battery). Though consumers are likely to favour technologies that lower their energy costs, periods of low wholesale energy prices tend to coincide with periods of low demand and therefore a high proportion of renewable energy input.  So these technologies will reduce carbon emissions and bills. 

Regulations will struggle to keep up with the complexity and innovation as this sector develops. Using an average grid carbon intensity will fail to incentivise or account for these valuable approaches.

As an 'energy consuming product' it makes far more sense for regulations for buildings to move to energy consumption rather than carbon emissions . Of course, the lower the energy consumption, the less energy is needed and the easier it will be to lower carbon emissions in the electricity supply.

Yet to be determined is what measure of energy we're talking about. If it is straightforward energy use, then one kilowatt hour (kWh) of gas burned to heat the house will count the same as a kWh of electricity taken from the grid. If, instead, it is Primary Energy (which takes into account conversion efficiencies from the original fuel), then electricity use will count more highly than gas.


2.'compared to today's standards'

Progress on carbon emissions is often measured against 1990 levels - the base year for Annex I parties to the Kyoto Protocol, the countries that signed up in 1997. The UK Zero Carbon Homes policy was enacted in 2007, and progress on energy efficiency standards for buildings has been measured relative to a building constructed to 2006 building regulations.

Improvements in energy efficiency of new build homes has been less than impressive. In the 12 years since 2006, the regulated carbon emissions from a new home built in England is only 29% lower than a house built in 2006. Scotland has pushed further forward, homes built here achieve carbon emissions levels 45% better than 2006.

Significantly, the comparison will be relative to today's performance levels. Progress to date will not count towards the mission.


3. 'include a building's use of energy for heating and cooling and appliances'

Until now, Building Regulations have only including 'regulated' energy - that used for heating, hot water, pumps fans and fixed lighting. In homes the regulations ignore energy used for cooking, fridges, freezers, washing machines, dishwashers, clothes dryers, audio visual equipment, IT equipment, plug in lighting and charging battery powered devices.

Housebuilders argue that they shouldn’t be held responsible for the electrical equipment that people use in the homes they build, and the government has up until now accepted that argument.

But why stop there?  Surely housebuilders cannot be held responsible for how often people choose to take a shower, or the fact that they don't want to wear thermals and down jackets while they're watching TV. The precedent of taking an average for domestic hot water use and internal temperature is well accepted, so there's no reason why we shouldn’t regulate based on an average electricity use for appliances and gadgets too.

Still to be clarified is how appliances will be defined – what will be included in electricity use. SAP includes Appendix L with a methodology to calculate the energy use for lighting and electrical appliances and cooking, but it is not clear what range of electrical equipment is included in this estimate and what is not, or indeed whether this estimate of energy for appliances will be used for the Mission

Achieving the Mission

The Solar Trade Association has commissioned analysis by Think Three Consultancy on the future direction for building regulations in a world of low-carbon electricity. The report used SAP 9.92 with new SAP 10 carbon emissions factors to model the energy use a number of house types with a variety of combinations of heating technologies and fabric performance. The 3-bedroom, 94m2 end terrace house modelled in the report, has been used to assess potential approaches towards reducing energy by 50% from today’s performance.

For a home like this built to current regulations in England, space heating and hot water are the dominant energy uses. However, the total of regulated and unregulated electricity use for appliances, lighting, pumps and fans represents 41% of energy use.

Increasing the fabric specification of the building significantly (to Passivhaus levels) greatly reduces the demand for space heating, but leaves all the other energy demands unaffected. A solar PV system of 3.9kWp (12 panels based on high performance panels available today) would be easily accommodated on a house of this size and would bridge the gap from this specification to the mission target.

Improved fabric in combination with a heat pump reduces the space heating and hot water energy by the coefficient of performance of the heat pump (assumed to be 2.5 for heating and 2.0 for hot water). A solar PV system of only 1.2kWp (around 4 panels) would enable this design to meet the Mission target.  

Clearly designers will look for the most cost effective combinations, which as the cost of solar energy declines could involve more solar than this analysis suggests, but given the inclusion of appliance energy use, there seems to be no way to get to 50% reduction that doesn't need solar electricity generation on the building.

Conclusions

1. The Mission can be achieved without the development of fundamental new technological approaches.  Single self-build homes and small developments of social housing are routinely being built to Passivhaus levels of fabric efficiency today. Heat pumps and solar PV are available today. The challenge is more around helping the construction industry deliver high specification fabric efficiencies at volume.

2. The inclusion of energy use by appliances means that the target simply cannot be achieved without some element of renewable electricity generation on the building.

3. The requirement for on-site renewable generation will be even more the case for buildings with form factors that give lower heat losses such as terrace homes and apartments – here there are less gains to be made by improved building fabric and more efficient heating systems.

4. Gas heating currently has Primary Energy Factor (PEF) of 1.222 whereas electricity has PEF 1.738 (SAP10 figures). Unless the PEF for grid electricity falls over the period, a move to electric heating technologies from gas heating will have smaller benefits if the metric is Primary Energy. The more renewable generation on buildings, the more contributions these can make to reducing the PEF of grid electricity.

5. In recognition of the above, forthcoming updates to building regulations should be framed in a way that encourages the use of solar PV on new buildings. 

Housebuilding Rates Unaffected by Higher Energy Efficiency

So Where's the Cliff Edge?

When faced with  potential legislation that would require them to build homes that use less energy, emit less carbon dioxide and reduce energy bills for their customers, housing developers have often expressed concerns that this would increase their costs and reduce the number of homes that get built.  Westminster politicians, concerned themselves about the 'housing crisis', seem to have bought into this argument and there has been no meaningful tightening of the building regulations for energy efficiency in England and Wales since 2010.  In 2015, plans to have regulated that all new homes would be net zero carbon emissions were dropped and as yet there is no sign of any interest from government in making new homes more energy efficient.  Instead of being zero carbon, a new home in England built today still emits 71% of the carbon of a new home built in 2005.

By contrast in Scotland, ministers pushed on with improvements to energy efficiency in new homes and new regulations introduced in 2015 mean that carbon emissions from newly built homes in Scotland emit significantly less CO2 than similar homes in the rest of the UK (around three quarters).

So now it is possible to test this assertion that building more efficient homes would reduce the numbers by comparing what happened in Scotland after the rules changed to what happened in England.

The graph shows the number of homes built by private developers in Scotland as a percentage of the number of homes built in England by private developers for each quarter between 2010 and Q3 2017 (the latest quarter for which data for both regions is available).

The rate of housebuilding in Scotland remains within historical norms despite significantly tougher energy regulations

With a population of 5.4m compared to England's 55.2m, the ratio might be expected to have a long term average around 10%, and indeed this is the case.

What is also clear is that since Q3 2015 when the new regulations came into force, the rate of housebuilding in Scotland has remained within its long-term range.  Where is the cliff edge of which we were warned?  Why don't the higher costs in Scotland put off house builders from building?  The answer is called the residual valuation model for land pricing.  Given clear guidance on direction of travel of policy, builders will adjust the amount that they are willing to pay for land.  The houses still get built, the builders still make money.  All that happens is that the windfall to the landowner when land achieves planning permission gets a tiny bit smaller.

So those local authorities that are lining up to fill the gap left by Westminster inaction by using their local plans to require higher that building regulations performance should take heart from the evidence and press on with their plans.

This article is an update of an earlier blog.

What is Energiesprong?

Deeply revealing - the depth of the window reveals indicate the thickness of insulation in warm, comfortable Energiesprong homes.  Image: Energiesprong International

 

Could this Idea from the Netherlands Crack the Toughest Challenge in Energy Efficiency?

Into the gaping hole in UK energy efficiency policy (see previous blog) left by the UK government inaction and disinterest springs Energiesprong, a concept that originates in the Netherlands and could totally revolutionise the way we approach domestic energy efficiency.

Energiesprong translates as 'Energy Leap', and in contrast to the piecemeal, step by step approach that UK government has been trying to prod us down, Energiesprong aims to do it all in one go.  An Energiesprong refurbishment must meet five simple requirements:

1. The finished house should be zero energy - over the course of each year it generates sufficient energy to heat the house, provide hot water and power household appliances.
2. The renovation work is done in only one week
3. The residents do not have to leave their property while the work is going on
4. The work is covered by a 30-year warranty covering the indoor climate and the energy performance of the house
5. The combined savings from energy bills and maintenance as a result of the renovation should finance the cost of the work

The requirements may be easy to set out, but the technical challenges they present to the construction sector are far from simple.  How to cost effectively making millions of individual and unique homes cosy, comfortable and cheap to run.  Nothing less than a new era of mass-customised construction  is required.

Insulated wall panel being craned into place at the first Energiesprong in the UK
Image: Energiesprong International

The prevailing technical approach to an Energiesprong renovation is for the house to be surveyed externally to millimetre accuracy with laser scanners.  A highly-insulated timber frame cladding system is made in a factory off-site before arriving on a lorry and being lifted into place by a crane and attached to the existing walls.  A new roof, almost always covered with solar panels is lifted on top of the existing roof (sometimes even leaving the old tiles in place).  In effect you build a whole new house around the existing one.

Windows and doors are removed and replaced, and heating systems go electric - typically either heat pump or electric panel heaters, depending on how far the insulation has driven down the space heating demand.  Solar thermal, battery energy storage and ventilation may also figure in designs.

The fourth and fifth requirements are utterly crucial to the whole thing working, as they make it 'investable' .  Residents pay an 'energy services fee' which is the same as their current energy bill, but get a better looking, warmer and more comfortable house.  The goal is for the cost savings on future planned maintenance (e.g. window replacements, roofing renewal, heating system replacement) plus the energy services charge to total up to a figure high enough to be able to give financial markets a sufficient return for financing the upfront costs.  If this can be achieved, then the scope for expansion of the scheme is effectively unlimited.  It works without government support.  It is completely scalable and social landlords can raise private sector finance to refurbish their entire stocks of housing.





Row of Energiesprong homes, Melick, Netherlands. 
Image: Energiesprong International

It is this possibility, of funded deployment at scale that has got the construction industry, social landlords and local authorities so excited about Energiesprong.

Consider the challenges, though.  At the current cost of energy, Energiesprong UK estimates that the whole refurbishment must be done for around £40,000 per house to be properly self-financing.

For this cost point to be reached, serious economies of scale need to be unlocked.

Energiesprong UK, and sister organisations in France, Netherlands and other countries aim to create these economies of scale by encouraging social landlords with large portfolios of property to bring forward volume refurbishment programmes and at the same time encourage the construction sector to develop the innovative products and techniques that will be needed to deliver these projects at low cost.  This stage could then be followed by a roll-out to owner-occupied homes and even new build properties, where the model might finance the difference between building regulations energy efficiency levels and building to zero net energy.

So far, around 2,000 Energiesprong homes have been completed in the Netherlands, of which around 60% were renovations of existing properties and 40% new builds.  The first Energiesprong homes outside of the Netherlands have recently been completed in a pilot of 10 homes in Sneinton, Nottingham by Melius Homes for Nottingham City Homes.

The pilot programmes so far undertaken have cost more than the £40k target, and so have required top-up funding, but the volumes have been relatively small, predominantly pilot programmes.

Implications for Policy and Energy Efficiency

A couple of observations on current approaches to energy efficiency and government policy arise when considering the great potential from Energiesprong.

1. Many government policies are based on the prevailing concept of a long journey of many small steps.  For example the Energy Efficiency Standard for Social Housing (EESSH) in Scotland requires social landlords to lift the energy efficiency of all homes, and it is envisaged that the minimum performance will ratchet up in small steps over time. This approach is not compatible with Energiesprong, for which it would make more sense to set targets for the average efficiency of stock.  This would give social landlords the flexibility to refurbish homes to a very high level and work their way through the whole stock year by year.  To allay fuel poverty concerns for people living in the homes that get dealt with later on, perhaps all stock should reach a minimum before an average score could be used.
2. Funded schemes, such as 'rent-a-roof' solar could be a complete dead end and indeed prove an impediment to the whole-house approach.  If you want to stick a new, cosy roof over an existing one as part of an Energiesprong refurb, but someone has already signed up to a 'free solar' plan which hands over the roof for 25 years to a financier, then you may find that you cannot remove the panels without paying to get out of that contract.  Similar, funded schemes, based on the Renewable Heat Incentive (RHI), for example for biomass boilers, could also prevent progress, as the RHI payment is based on the heat provided, which would be curtailed in a more energy efficient building.



Before and After.  Energiesprong refurbishment for Lefier Housing Association in the Netherlands. 
Image: Energiesprong International

It's About the Regeneration not the Generation

The main difference between Energiesprong and previous attempts at improving energy efficiency is the potential it provides for the redevelopment of entire streets and localities.

The whole outside of the house is renewed, and as the images show, the improvement can be extraordinary.  The scope for regeneration of tired old housing estates has got social housing providers and local authorities really interested.  Suddenly we're not only talking about energy saving, we're talking about regeneration and investment in the value of housing assets, funded by energy savings.

Consequently, it is possible that even before the £40k/house cost target is reached, significant projects can go ahead by combining with funds earmarked for the redevelopment of deprived areas.

Either way, the possibility of regenerating whole areas, with funding either partially or wholly paid for from future savings on energy bills is revolutionary and well worth reaching for!

Useful Resources

Energiesprong Foundation
Gallery of International Energiesprong Projects
Energiesprong UK
Energiesprong France

A Brief History of UK Energy Efficiency Policy

The track record of UK initiatives to encourage us to make our homes more energy efficient has been patchy to say the least.

 
The schemes come and go, but the results are depressingly consistent.

ECO

A range of government schemes have required the larger energy providers to invest in energy efficiency measures such as loft and cavity wall insulation for homes. The current version is the Energy Company Obligation (ECO), but before that we had CESP and CERT and others. This bizarre concept - making a business responsible for implementing measures that reduce demand for its own products - seems like putting a fox in charge of security improvements to the chicken coop. It is perhaps unsurprising then that foot-dragging, missed targets and ineffective measures have been the result.

In 2014, many of the energy suppliers were fined for failing to meet their targets to install insulation. British Gas was fined £11million, a development which their PR department brazenly promoted as a charitable donation.  One is left wondering if the energy companies considered these fines a small price to pay rather than helping people spend less on energy.

Measures installed under this scheme crashed by more than 80% after 2012 when a panicking George Osborne announced huge cuts following a Labour proposal to cap the prices people pay for energy.

Green Deal

Greg Barker's Green Deal scheme to 'transform the energy efficiency market' was in trouble almost from the start. Having told us that he'd struggle to sleep if the number of home improvements it financed was less than 10,000 in the first year, the actual number came in at 626.

In what now looks like a rather desperate effort, Greg managed to convince the Treasury to throw in a few hundred millions to the Green Deal Home Improvement Fund (GDHIF), to give a further cash-back grant to householders who installed energy efficiency measures. Most of this stop-start funding was spent on boiler replacements (and how many of these would have happened anyway as they reached end of life is open to debate). The scheme was ignominiously withdrawn after writing only a few thousand energy efficiency loans.

The offer to consumers was complicated and unappealing. The interest rate was a hefty 7%, which compares unfavourably with mortgage finance. Only measures that met the so-called 'Golden Rule' could be fully financed - where the estimated savings on energy bills were greater or the same as the repayments collected through your energy bills. What this all added up to was - go through all the hassle of having all this work done in your house and your energy bills will be about the same as they were before.

The Green Deal Finance Company is now in private hands, but it is still unclear how the new owners will address the fundamental shortcomings of the scheme.

Feed in Tariff and Renewable Heat Incentive

These schemes pay for renewable energy - power and heat where homes and businesses install technologies such as solar PV panels, solar thermal panels, heat pumps and wood chip burning stoves in their homes or businesses. The intention was that these would provide long-lasting and stable support for renewables after a series of start-stop grant schemes that had preceded them.

The Feed in Tariff (FIT) is due to close in 2019 after a tumultuous few years in which government struggled to keep up with rapid reductions in the cost of solar PV panels. As a result of the payments being fixed while the costs fell sharply, the financial returns from the scheme rose rapidly. Returns of 15-20% were not uncommon, payback periods as short as four or five years reported. As more and more people joined the party the budget ballooned. Cue panic in Whitehall, an over-correction on the tariff rates and a return to the boom-bust market from which the scheme was supposed to mark a departure.

The Renewable Heat Incentive (RHI) for heat generating renewables came in after the first FIT crisis, and as a result was designed with many more controls to stop a runaway deployment if the tariffs were set too high (with the notable exception of Northern Ireland where the executive for some reason removed the controls and blew the budget - the whole Northern Ireland budget!). In consequence, the RHI suffers from a paucity of ambition and has only resulted in a few tens of thousands of households replacing their heating systems with a low carbon technology (33,500 new domestic installations of solar thermal, heat pump and biomass boiler from April 2014 to November 2017)

MEES 

The Minimum Energy Efficiency Standard (MEES) applies in England and Wales and requires private landlords of both domestic and non-domestic properties to ensure that their properties meet a minimum level of energy efficiency.  Buildings that do not cannot be re-let after April 2018 and cannot be let at all after April 2020.

Unfortunately, as I revealed in an earlier blog, a landlord can apply for an exemption if they cannot do the required improvements without upfront costs, which relied on the Green Deal being available.  But this has now gone, leaving a loop-hole in the legislation so large you could drive an un-insulated house with broken windows through it.  Similar legislation being consulted upon in Scotland only deals with domestic properties, but sensibly places a limit on the maximum cost for a landlord.  So far, there's no apparent interest in fixing this mess at Westminster.

EESSH

The Energy Efficiency Standard for Social Housing (EESSH) is legislation in Scotland that requires social housing providers to ensure that their housing stock is all above a minimum energy efficiency level by the end of December 2020, with an intention to gradually ramp up the required levels over time.

EESSH looks like its already producing some significant investments in Scottish social housing.  It really does look like the one to watch, at least of all the schemes listed.

Is There Another Way?

What all these schemes have in common is that they deal piecemeal with the challenge of making our buildings more energy efficient. They imagine that the 'journey' to having an energy efficient home fit for the future is taken one small step after another. First insulate your cavity walls and loft. Then change your boiler to an efficient new one. Have some solar panels on that roof. Now replace your whole radiator system take out your efficient new boiler and fit a heat pump.

Many also rely on government spending, a fickle foundation upon which to base investments in housing stocks or to build long-term business plans (as those of us in the solar industry will attest).

With the demise of the Green Deal, and no sign of anything to replace it, there's a huge hole in the government's policy to meet forthcoming carbon budgets. This is not something that has gone unnoticed by the government's own Committee on Climate Change (CCC), which in its 2017 report gave government policy for residential energy efficiency a red light for able to pay households and an amber light for low income households.

It is into this gaping hole left by the UK government inaction and disinterest springs Energiesprong.  This is a concept that originates in the Netherlands that could totally revolutionise the way we approach domestic energy efficiency and it is the subject of my next blog.

The Carbon Intensity of UK Grid Electricity

What it Means for Low Carbon Buildings

Take a look at this chart. It's nothing short of astonishing. Up to 2012 the amount of carbon dioxide emissions associated with the delivery of one unit (kilowatt hour, or kWh) of electricity in the UK was hovering around 500gCO2/kWh. Since then, the amount of carbon dioxide that is emitted for each unit of electricity has plummeted. In 2016 the average was 269gCO2/kWh, a fall of nearly half in only four years. This change has far-reaching implications for regulators, not least those involved in ensuring the low carbon transition of the UK building stock, both newly constructed buildings and the improvement of the existing stock.

So what's behind the fall?

The first factor is the retreat of coal-fired power stations. In 2012, the government's Digest of UK Energy Statistics (DUKES) has coal fired power stations producing 44% of our electricity nuclear plants were suffering from outages and gas prices had risen, so coal use was at a high. By 2016 the corresponding figure for coal was only 9%. In the same period, gas fired power stations rose from 24% to 42% of UK power generation. This matters for two reasons. First of all, because coal is made up of long-chain hydrocarbons, with a higher ratio of carbon atoms to hydrogen atoms it produces about 60% more carbon dioxide than natural gas for each unit of heat energy produced in burning. Second, gas is more often burnt in a Combined Cycle Gas Turbine (CCGT) power plants with conversion efficiencies of up to 60%, compared to 40% for conventional steam turbines.

The second factor is the increasing contribution from renewables in the electricity supply. Enormous amounts of wind energy, biofuel fired generation and solar energy have come online. In 2012 renewables and 'other' represented 11% of UK electricity supply. In 2016, this had risen to 27.8%.

As a result the average carbon intensity of electricity in 2016 at 269 gCO2/kWh was only just higher than that for gas (216 gCO2/kWh). When you add in an efficiency for a gas boiler at (say) 80%, the gap disappears.

This is huge.

For years electricity has been the bad boy in low carbon building design. People fretted as a series of reports from the Energy Savings Trust showed that heat pump installations in the UK were operating nowhere near their advertised efficiencies and were consequently underperforming gas boilers for carbon emissions. Simple resistive electrical heating by panel heaters or immersion heaters for hot water were to be avoided at all costs.

Four short years later and all this is is turned on its head.

And we're only just getting started with renewables. In September, Dong Energy announced that it would move forward with the world's largest offshore wind farm, Hornsea 2 off the Yorkshire coast, with development costs that had fallen by half compared to previous offshore farms. A couple of week later, and not to be outdone, the UK's first subsidy-free solar farm was announced. It's still a bit of an outlier combining solar with battery energy storage and using pre-existing grid connections from with an earlier development, but it's a clear sign of the direction of travel. The carbon intensity of grid electricity is heading only in one direction.

But there's another wrinkle to consider. The carbon intensity of the grid is not a static value. It varies constantly as the mix of generators fluctuate to meet different levels of electricity demand and in response to changes in wind and sunlight. On 11th June this year, it was windy and sunny at the same time. Records tumbled. The carbon intensity of grid electricity in the middle of the day on was below 80gCO2/kWh.

So now the moment when you choose to take power from the grid is a strong determinant of the actual instantaneous carbon emissions your electricity use is creating.

Some uses of electricity - for example for preparing domestic hot water, or to some extent space heating buildings could be relatively time independent.  If I'd known ahead of time that carbon emissions would be so low on 11th July, I'd have been able to set a timer for my immersion heater to heat water for me at midday and got my tank of hot water at fully one third of the carbon emissions of using gas heating.

And the technology to do this is just around the corner.  This awesome new grid carbon intensity forcasting service has been recently launched by the National Grid the Met Office and WWF, with an API that software developers could use to do just this kind of thing.

 

So where does this leave low carbon building?

The current building regulations in England and Wales were last reviewed in 2012 and set minimum carbon emissions rates that developers must design to. The carbon intensity of electricity in the approved calculation (the Standard Assessment Procedure or SAP) is currently 519gCO2/kWh, which was accurate at the time. Now it is woefully behind the curve.

Buildings are normally intended to be long-lasting. If we allow ourselves to imagine a future where digital technologies, the smart distribution of electricity, demand response, energy storage and renewables combine in a so-called 'Smart Grid' then a number of significant observations about low carbon building emerge:

• Even based on the current carbon intensity, never mind the future direction of travel over the life of a building, it is utterly beyond me that any new build or significant refurbishment should include gas heating.

• The current enthusiasm among UK policy makers and local authorities for district heating (for example this recent consultation by Scottish government) could also be a troubling dead end. District heating itself is neither intrinsically clean nor green - it all depends what heat source you put at the other end of the pipes you're going to dig up all the streets to install. Gas fired combined heat and power may be seen as low carbon at the moment, but how long will it look so appealing if electricity continues on its current path?

• Building codes are currently focused on regulating carbon emissions. In a world of low carbon electricity you can meet a carbon target with a draughty garden shed full of electric fan heaters. It's time to move to energy targets (kWh/m2) to create buildings that sip energy and liberate power for the demands created by the electrification of transportation.

If I was building my own Grand Design right now, my future-proof forever home based on these observations here's what I'd go for:

• High levels of insulation and air tightness to drive down space heating demand to a practical minimum

• Eliminate the wet heating system - I'd go underfloor electric coupled to a high thermal mass floor to allow price and carbon responsive electricity purchase to heat the slab at times of excess renewable generation

• Direct electric hot water cylinder - again allowing price-responsive purchase of electricity as well as diversion of excess generation from...

• the inevitable....beautiful solar panels on the roof - as many as possible!

Could this be the future direction energy efficient buildings? What do you think?

Energy Efficiency Regulations - Private Rented Properties

England and Wales 

Is the legislation in England and Wales Collateral Damage of the Green Deal fiasco? 

 In 2015 UK Government introduced legislation creating a minimum energy efficiency standard for homes and commercial properties that are rented out - the Energy Efficiency (Private Rented Property) (England and Wales) Regulations 2015 

This legislation captures around 9% of private rented properties in England (see my earlier blog: How Energy Efficient is UK Housing Stock?) - the Impact Assessment reckoned this would be around 360,000 homes that will need to have an EPC raised from F or G level (based on 2012 housing stats).

These houses would have needed an energy efficiency upgrade upon being re-let after April 1 2018 and by April 1 2020 if the tenancy didn't change first.

The legislation also covered non-domestic buildings. The impact assessment reckoned that 18% of business properties have an EPC of F or G this adds around 200,000 buildings to the total requiring an energy refurbishment.

However, in a ham-fisted attempt at joined up legislation, the government linked the legislation to the Green Deal.

This hopeless scheme was going to "transform Britain's buildings" by offering funded energy upgrades. Householders and social landlords were going to queue up to insulate their homes because the cost of repaying the loan would be less than the money saved on future energy bills. (Who could have possibly predicted that this wouldn't be an easy sell?)

It was ignominiously withdrawn in July 2015 having written only 14,000 Green Deal financing schemes due to its bewilderingly bureaucratic design and the unappealing interest rates offered on the loans.  (Damning National Audit Office report here)


How has the withdrawal of the Green Deal impacted the regulations on privately rented homes?

Here's an extract from the Impact Assessment associated with the regulations for private rented properties:

From 1st April 2016, landlords of a domestic property may not unreasonably refuse requests from their tenants for consent to energy efficiency improvements, where financial support is available that ensures no upfront costs to landlords for the measures, such as the Green Deal, the ECO, tenant’s own funds, or national or local authority grants.  

 From 1st April 2018, all new lettings or tenancy renews of applicable private rented properties in the domestic and non-domestic sectors should be brought up to a minimum EPC rating of an ‘E’ if this can be achieved with no upfront costs. 

By adding the requirement that the only energy efficiency improvements that have to be made are those with no upfront costs, the whole thing is effectively defunct. With the Green Deal gone, and precious few local authority grants around the only way that a building is going to be improved is if the tenant pays for it!

The regulations need to be urgently amended to require the Landlord to upgrade the property - perhaps with a cost cap (see information on new Scottish regulations below).

Meanwhile in Scotland... 

This issue looked as if it had been kicked into the long grass in Scotland after the working group tasked with developing Regulation of Energy Efficiency for the Private Sector (REEPS) seemed to get bogged down and put on ice in 2015, (naturally Westminster was blamed for this).

The only regulations affecting private landlords was a rather lame requirement to get an energy assessment (with recommendations) done - but without having to  action any of the recommendations.

However, Scot Gov has sprung into action and designated energy efficiency as a National Infrastructure Priority and published a consultation on a Scottish Energy Efficiency Programme (SEEP).

 Plans for energy efficiency requirements in the private rented sector have also been revealed in a consultation published in April 2017. The proposal is to legislate for privately rented houses covered by the so-called "repairing standard" which will need to meet a minimum energy efficiency rating on the Energy Performance Certificate (EPC).

For new tenancies after 1 April 2019 the house will have to achieve an EPC rating of no worse than EPC band E. After 1 April 2022 (called the backstop date) all privately rented homes will have to achieve this minimum standard, irrespective of a tenancy change. 

Scottish goverment estimates that this change will affect 30,000 properties.

 Where the EPC shows a band of F or G, the owner will need to have a "minimum standards assessment" carried out and lodged on the EPC register before renting out the property. This new assessment is closely based on the EPC methodology, but will include recommendations of the lowest-cost technically appropriate measures to bringing the house up to the required energy standard.

 The owner will have to bring the property up to the standard required by the assessment within six months of the date of the assessment, but subject to a proposed cost cap of £5000.

The minimum standard ratchets up to EPC D, for new tenancies after 1 April 2022, with a backstop date of 1 April 2025.

The property owner will be responsible for getting the improvements required by the minimum standards assessment done. Local authorities will have the power to issue civil fines of up to £1,500 against any owner who does not comply with the standard.


The proposals for Scotland look very good.  If implemented, it would result in a clear process that can deliver low carbon buildings in this sector through the regular tightening of the requirements (beyond those mapped out to 2025).  The proposals seem to be a good mixture of ambition and realism.

By contrast, England and Wales is in disarray in this area and as in the regulation of so many other sectors (new homes, social housing), Scotland is showing the way.