New Building Regulations for Scotland

In June 2022 the Scottish Government published its consultation response on changes to further tighten the Building Regulations for energy efficiency.  New developments in Scotland seeking a Building Warrant after 1 December 2022, will need to meet the new regulations.

Although most respondents to the consultation were in support of a higher performance target (delivering a 57% reduction in CO2 emissions), the government instead opted for the lower performance target which is expected to reduce the CO2 emissions of new homes in Scotland by 32%.

The central element of the building regulations for energy is the so-called 'Notional House Specification' which defines the target that a developer must meet. (For a full explanation of how the Notional House Specification works see this earlier blog).

The 2022 Building Regulations in Scotland gives three Notional House Specifications - one for homes heated with a heat pump, another for homes heated by a heat network and a third based on mains gas  for homes using any other heating systems.

The table below contrasts key elements of the new Notional House Specification with those in the previous version of Scottish Building Regulations and also with the new regulations that came into force in England this year.

As can be seen, the new Scottish Building regulations require a significant improvement in U-values (insulation) and airtightness compared to the current (2015) regulations.  They also come in slightly better than the latest regulations for England (it would have been a major surprise if they didn't!)

Of interest to solar industry participants will be the increase of PV provision in the gas heated notional house compared to the 2015 regulations.  

In 2015 Scotland became the first of the nations to add solar PV to the notional house - the amount asked for was the dwelling total floor area in m2 x 0.01kWp, which corresponds to 20Wp of solar per 1m2 of ground floor area (for a two storey building of equal ground and first floor areas).  The new requirement is for 0.4 x ground floor area in m2 / 6.5 -  which works out to be 62Wp of solar per 1m2 of ground floor area - around 3 times more solar per house.

Other Changes

Scottish Goverment also changed the way the benefits from solar are taken into account in the calculation.  The energy and carbon benefit of on-site generation is capped at the level assessed as being used on site (excluding the energy exported the grid).  This change is likely to incentivise the use of technologies to store excess solar energy for later use - for example battery storage or energy diverters that heat hot water with excess solar energy.

Good News for Solar?

The new regulations look like great news for solar in Scotland.  The Building Regulations are 'solution neutral' allowing developers to choose a combination of heating system, insulation and on-site generation that equals or exceeds the performance of the Notional House Specification.  Since both developers and house buyers prefer gas boilers to heat pumps, this regulation change is likely to increase the amount of solar installed on new homes in Scotland because of the three-fold increase in panel power in the specification.

However, the cloud on the horizon for the solar industry is another piece of legislation - the New Build Heating Standard, which will remove the gas boiler option for housebuilders by banning their use in new homes.  

Under these Building Regulations, once a housebuilder is forced to use heat pumps, the requirement for solar drops away because the Notional House Specification for heat pump heated homes does not include it.

Solar PV and heat pumps are a great match, with solar offsetting higher running costs of heat pumps - why would Scottish Government have no solar on the heat pump specification?  It all boils down to the cost for the developer - the regulations have been set up to encourage housebuilders to consider heat pumps before the 2024 regulations, and the notional house has been set up to try to level the playing field for build costs - leaving waste water heat recovery and solar off the heat pump specification.

No heed has been paid to the increased running costs the home owner will suffer in a heat pump heated home compared to a home with a gas boiler and solar PV.

Once there is a regulatory requirement in place to use a heat pump, then then the incentive to try to lower the cost of a heat pump installation versus gas plus solar falls away.  Scottish Government should commit to review the building regulations at the same time as bringing in its New Build Heat Standard to require solar PV on heat pump heated homes too.  This way it will ensure a just energy transition and reduce the risk of a consumer rejection of heat pumps.

The Social Housing Decarbonisation Fund – A Role for Solar PV

Padiham Near Burnley where 108 electrically heated homes were improved with external wall insulation, new windows and hot water systems, and Clearline fusion roof integrated solar PV by social landlord Places for People

On 19th October, the UK government revealed its much anticipated Heat in Buildings Strategy.  Headline writers entirely focused on only one element of the announcement -  the Boiler Upgrade Scheme, a plan to give grants of £5,000 to people replacing fossil fuel heating by installing a heat pump in their own home.  (See for example coverage from Sky News, Daily Telegraph, The Guardian, The Sun, BBC News).

However the Strategy contained other initiatives which, while less-publicised, better address the barriers to the transition to electric heating - by helping mitigate both their high running costs and expensive installation. These funds aimed at social landlords and Local Authorities takes a more holistic approach since they can also be used for measures that tackle running costs by reducing heating demand and generating power on-site.

The Social Housing Decarbonisation Fund

Less reported, but with a budget many times higher than the headline-grabbing Boiler Upgrade Scheme is the funding announced for the next three years for delivery through Local Authorities and Social Landlords.  The Social Housing Decarbonisation Fund (£800m over three years) is for energy improvements to social housing and the Home Upgrade Grant (£950m) will be administered by Local Authorities and support energy efficiency improvements for low income households.

For the Social Housing Decarbonisation Fund, the approach is summarised as follows:

• Fabric first – heat loss prevention is prioritised before other energy efficiency measures
• Worst first – homes with lower starting energy performance attract more funding
• Upon completion homes must achieve a minimum Energy Performance Certificate (EPC) rating of C and maximum space heating demand of 90kWh/m2.year

It is set up as a competition, with applicants scored on how well they meet the goals above, as well as for deliverability and cost-effectiveness.  The landlord contributes at least 1/3 of the cost of the upgrade with 2/3 coming from the fund.  If a landlord takes the full grant and adds the minimum contribution only, then the amount that can be spent on each type of property is given below.  Landlords can elect to spend more on the property, but the extra is then provided by the landlord.

Starting EPC	Maximum Budget Supported (with maximum grant and minimum landlord contribution)
D	£15,000
E	£18,000
F	£24,000
G	£24,000

These are pretty chunky amounts.

Eligible measures are anything that improves the EPC, with the exception of new fossil fuel heating systems.  Low carbon heating is encouraged, but only after fabric measures have been implemented.  The tenant must be left better off - with lower energy bills.

This is where solar PV comes in -  due to the high cost of electricity compared to gas, replacing gas heating with electric heating will increase energy bills, unless the starting levels of thermal insulation are exceptionally low and can be improved by a very large amount.  (See my earlier blog – Real-World Heat Pump Running Costs)

The complementarity of solar PV and heat pumps is well-understood by social landlords, as can be seen by reviewing the successful bids in the Social Housing Decarbonisation Fund Demonstrator, which were announced March 2021 and I have put into summary form in the table below.

Bid	Award	Number  of homes	Measures
Aberdeen City Council	£2.2m	100	EWI, ASHP, PV
Argyll & Bute Council	£1.2m	130	EWI, ASHP, PV
Clackmannanshire Council	£0.3m	15	EWI, glazing, PV
Cornwall Council	£1m	75	EWI, ASHP, PV
Fenland District Council	£4.5m	160	EWI, glazing, PV
Leeds City Council	£4.2m	190	EWI, ASHP, PV
Barking and Dagenham	£9.6m	230	EWI, ASHP, PV
Manchester City Council	£3.1m	164	EWI, ASHP, glazing
Northampton Borough Council	£3m	150	EWI, ASHP, PV
Nottingham City Council	£2.3m	104	EWI, ASHP, PV
Nottinghamshire County Council	£0.8m	25	EWI, glazing, floor insulation
Kensington and Chelsea	£19.4m	535	EWI, ASHP, PV
Stratford-on-Avon DC	£1.4m	69	EWI, ASHP, PV
Stroud District Council	£1m	50	EWI, ASHP, PV
Sunderland City Council	£0.9m	59	EWI, glazing, PV
Warwick District Council	£1.4m	50	EWI, glazing, floor insulation
Wychavon District Council	£5.8m	236	EWI, ASHP, PV

Key: EWI – External Wall Insulation, ASHP – Air Source Heat Pump, PV – Solar photovoltaic panels

Fourteen out of seventeen successful bids, covering 2,103 out of 2,342 (90%) of the properties to be improved have solar PV among the measures to be installed.  In fact only one project (Manchester) is installing ASHP without PV.

With a total cost of £62.1m, the demonstrator projects grant component is an average of £26,000 per property – higher than the current ceiling, but due to solar PV being such a cost effective way to improve EPCs, it is likely to remain a feature of projects in the future waves.

This system approach to improving properties comprising significant improvements to insulation to lower heat demand, and combining low carbon heating with solar PV to keep a lid on the energy bills for residents seems far more sensible than a crude upfront grant to help cover some of the extra costs of the heat pump installation alone.

That winning combination of heat pumps and solar PV is well-understood by experienced practitioners of energy retrofit working in the social housing sector.  By contrast, owner-occupiers encouraged by generous grants to install heat pumps may find themselves on the phone to their local solar PV installer soon after their first electricity bills land on the doormat.