Solar By Others

How to Get What you Want and not Get What You're Given

Architects, developers and planning officers often go to exacting lengths to make absolutely sure that they get the look that they're aiming for in a building. For houses that can mean specifying the type of brick, the tile on the roof, and specific styles of windows and doors. Even soffits and guttering do not escape careful scrutiny, selection and specification.

Damn right, too! These materials have a huge impact on the overall appearance of the house and should be defined carefully to preserve the integrity of the design, and the quality and sale-ability of the finished product.

Which makes it all the more surprising to find in developers' design packages a great big rectangle drawn on the roof labelled "solar by others" or "solar by specialist installer".

Surely you know that once you hand over your beautiful, carefully considered design to a Quantity Surveyor, if your specification does not nail down the materials you're looking for, then the words "solar by others" might as well say: "solar - the cheapest you can find, no I honestly don't care what it looks like - yes, I know I was really fussy about the exact make and model of cavity closer, but really, just get what you want for the solar - it's not like anyone will notice it's there."

It doesn't all look this good.  Image credit: ARPower

Solar PV is becoming more and more common on roofs. Incentivised by Feed in Tariffs, more than 800,000 households have now chosen to install solar as a retrofit. Building regulations in Scotland have made solar the norm on new homes and planning conditions in many local authorities (including zero carbon homes in London) also mean new homes are more likely than ever to need solar.

With the coming shift towards electric transport - (the speed of which I predict will take policy makers and energy companies completely by surprise), economies of scale for battery manufacture will drive the availability of cost effective electricity storage, and make solar an even more compelling feature of a mainstream home.

What you Need to Know

The cheapest panels have silver frames, a white backing sheet and polycrystalline cells. Sticking them on a framing system above the roof covering is still (only a little) cheaper than going inline with the roof. If you don't specify what solar you want, this is what you're likely to get.

Here are the choices you face, starting with those that have the greatest impact on 'kerb appeal'.

1. Panel Layout

The number one impact on the overall look of the building is the layout of panels on the roof.  Early design engagement with solar specialists means that cluttered designs fitted around other roofing features can be avoided.  Higher power panels can be selected to achieve energy goals in the most aesthetically balanced way.  See also this guidance on panel design by the  Campaign to Protect Rural England.

2. Frame colour. 

Solar panel frames are most commonly either silver or black. Both have a protective anodised surface finish, but a silver (natural) colour avoids the dyeing process needed to make a black frame so is slightly cheaper.  In most (but not all) situations black frames are considered the most discreet and harmonious choice.


3. Mounting System. 

Panels can be mounted on metal racking above the tiles or slates or conventional roof covering, or they can be sunk into the roof covering (roof integrated), replacing the conventional roof covering and looking more like an intended part of the building design and less like a 'bolt-on'. Many systems use a 'top clamp' arrangement to hold down the panels to the framing, but some systems have hidden fixings, resulting in a less cluttered finish above the plane of the panels.

Roof integrated systems with visible clamps (top) and invisible fixings (bottom) 

4. Backsheet.

A white backing sheet means you can use ever-so-slightly lower power cells in your panel for the same overall panel output (the white sheet reflects light and keeps temperatures a little lower so the same cells perform better). When combined with mono crystalline cells (which are not quite square and have missing corners), a white backing sheet will produce a characteristic pattern of diamonds running up the panel in columns.

Monocrystalline cells (left) and polycrystalline cells (right) in combination with a white backsheet showing the characteristic diamond pattern of a monocrystalline panel

5. Cell Type. 

Polycrystalline cells are sometimes a similar price to mono crystalline cells, but in times of over-supply often seem to fall further and faster. Right now modules based on polycrystalline cells are around 10% lower in cost than those based on mono crystalline cells. In general poly cells will look a bit bluer than mono, and may have little more colour variation across and between panels , but modern cell production technologies can mean that nowadays they rarely show the crystalline pattern that used to be so characteristic of this type of panel.

(More information on the differences between polycrystalline and monocrystalline cells can be found in this blog).

6. Cell Interconnections. 

Some manufacturers hide the bus-bars (silver strips at the top and bottom edges of the panel that electrically connect the cells together, but obviously this also adds cost. Some panels have cells with rear face connections so there's no silver lines visible on the top face of the panel.

How About Just Asking For Roof Integrated Solar?

For sure there are some great looking roof integrated solar systems available. But specifying roof integrated can still result in a wide range of outcomes when you hand it over to the commercial team. This is particularly the case for roof integration systems that give freedom to use any old panel. 

I took the pictures below at the same site and they show two phases of the same development.  The specification called only for "in-roof solar", opening the door to the silver-framed installations in the lower image which meet the letter, if perhaps not the spirit, of the specification. 

Both are roof integrated solar

For something that has such a big impact on the way a building looks, surely it's time for designers to take control of the solar they get, rather than giving the commercial team carte-blanche to go with the cheapest option offered.  

Unfortunately there’s no substitute for carefully choosing and specifying the product you want, just like you do for other building materials.

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.

The Merton Rule is Not Dead, Long Live the Merton Rule!

Can Local Authorities Still Require Energy Efficiency Higher Than Building Regulations?

The largest housing developers would very much prefer it if they were able to build the same house in Aberdeen that they build in Abingdon. If they can do this, then the cost of the architect and engineers to design their standard properties can be spread across more units, and their buying power can be increased by using the same component parts in every house they build. This is one of the ways they out-compete smaller, more local building companies.

For this reason they dislike local rules and regulations that affect the houses they build.

In 2008 UK government enacted the Planning and Energy Act, which among other things clarified that local planning authorities had the legal right to require energy efficiency standards in new homes that exceeded the national building regulations. This approach to pushing developers to build housing with an energy performance beyond the national minimum had become known as the 'Merton Rule' after the local authority in London that had pioneered the approach.

Here's what the Act says:

1  Energy policies

(1)A local planning authority in England may in their development plan documents, and a local planning authority in Wales may in their local development plan, include policies imposing reasonable requirements for—
(a) a proportion of energy used in development in their area to be energy from renewable sources in the locality of the development;
(b) a proportion of energy used in development in their area to be low carbon energy from sources in the locality of the development;
(c) development in their area to comply with energy efficiency standards that exceed the energy requirements of building regulations.

It has been estimated that around 50% of local authorities took advantage of the new clarity to build such requirements into their local plans.

National builders didn't like it. They didn't like it at all. Different local authorities chose to ask for 10% renewable energy on site, 20% renewable energy on site, Code for Sustainable homes level 4.

The national developers were faced with different requirements up and down the country, a situation further complicated for them by the fact that different local authorities enforced their planning requirements with different levels of enthusiasm and competence. In some areas, particularly those areas that combine both high housing need and low house prices, developers might find a planning requirement for renewable energy on new developments to be highly negotiable. Other local authorities, notably in the south, with high house prices that means developers are queuing up to build new homes there, have been far more successful at holding the line on the aspirations of their development plans.

It could be argued that this is exactly as it should be. The UK has very high geographical differences in house prices. Local authorities could set their local planning regulations to achieve the highest energy performance that was consistent with the economics of housing development in their area, specifically whether the value of development land is sufficient to cover the additional costs of more efficient homes.

However, in 2015 things swung back towards the large developers. The government of Cameron and Osborne announced a 'bonfire of regulations' to free business from costly red tape. The Housing Standards Review was formed to look at red tape afflicting the house builders. Developers successfully argued that this patchwork of local planning requirements was 'red tape' and the review concluded that it should be swept away.



The government chose to add the changes to the Deregulation Act 2015. Section 43 of this Act amends the Planning and Energy Act as shown below.

43 Amendment of Planning and Energy Act 2008
In the Planning and Energy Act 2008, in section 1 (energy policies), after subsection (1) insert—
“(1A)Subsection (1)(c) does not apply to development in England that consists of the construction or adaptation of buildings to provide dwellings or the carrying out of any work on dwellings.”

This amendment would remove the ability of local authorities (in England only) to require developers to exceed the building regulations for energy efficiency. Note that sections 1(a) and 1(b) remain, allowing local authorities to continue to require that a percentage of the energy consumption of a new development to be met with renewable or low carbon energy.

The passing of the Deregulation Act is, however, not the last word in this story. If you work in a local authority in England and a housing developer is telling you that you can't impose higher standards than building regulations on a development, they're wrong. The fact is that section 43 has not yet been brought into force, so the original Planning and Energy Act text still applies.

If you look at the Commencement Section of the Deregulation Act, you'll see how the various elements of the Act are to be brought into force.

Some sections come into force on the day the Act is passed in parliament, others some set number of months later. No special mention is made of section 43, so it falls under this provision:

(7)Except as provided by subsections (1) to (6), the provisions of this Act come into force on such day as the Secretary of State may by order made by statutory instrument appoint.

A check of statutory instruments shows that this has not yet happened for Section 43, fully two years after the Act itself was passed by Parliament.

In fact, during a Lords debate on the Neighbourhood Planning Bill, in response to a question by Baroness Parminter, Lord Bourn confirmed that it was the case that local authorities still have powers to require higher building standards:

"The noble Baroness asked specifically whether local authorities are able to set higher standards than the national ones, and I can confirm that they are able to do just that."

So there you have it, the Merton Rule lives on!

 Local authorities still have powers to drive low carbon development in England, and it's just as well because our central government seems to have lost the will to do so. It's down to the sustainability officers and planning officers to enforce their local plans and they have the power to do so.

The Residual Valuation Model

Why Legislators Have Nothing to Fear from Tougher Building Standards

Simple isn't it? A chain of logic that seems irrefutable.

Legislate to make developers build better (low energy) homes and their build costs will rise.
These homes will not command a higher price, because the market is dominated by the price of existing homes for sale.
So the developer will make less profit.
Less homes will be built at a time when the country desperately needs them.

Our politicians have been buying this argument again and again from well-funded lobbyists working on behalf of housing developers.

The flaw in the logic is the assumption that the developers costs have to rise when you increase building standards. They don't. This is because one of the main costs of building the house is what you pay for the land, and if everyone is faced with the same regulations, then the value of the land is driven down and the landowner makes a slightly smaller profit from the deal.

The windfall from selling land to developers is so significant that a small decrease in the value is not going to slow down the market.

Solar for Housebuilders

New homes with integrated solar.  Image: Viridian Solar

Solar is a fast-paced, innovative sector.  Even those of us who work in the industry sometimes struggle to keep up with the pace of change.  Most house builders have now experienced the use solar PV on at least some of the developments, however with the advent of stretching new building regulations in Scotland and Zero Carbon Homes for London arriving in October, it seems like a good time to provide an update for house builders on how this technology has rapidly matured in recent years.

Costs Keep on Falling

The reduction in the cost of solar PV in recent years has been breathtaking.  As global production capacity for the manufacture of solar PV panels has grown, the cost have fallen dramatically.

Economies of scale have also driven down the cost of  so-called ‘balance of system’ components like dc connectors, dc isolators and electrical inverters.  Innovation in roof fixing systems has lowered costs and different products to work with roof coverings of all kinds have increased the speed of installation.  For flat roofing, the emergence and certification of low-ballast flat systems reduce the imposed loads and the need to reinforce the roof structure.  A skilled workforce has achieved significant efficiencies in installation times.

If it’s more than a year since you last looked at solar for a housing development, you should look again at the costs. 

Aesthetic Solar Roofing Systems have Grown in Popularity

Image: Viridian Solar

Roof integrated solar systems replace the tiles or slates on the roof rather than sitting above the roof covering on metal rails.  When these employ  a ’black-black’ panel (one that has a black frame and a black backing sheet behind the solar cells), the panels look more like an intended and sympathetic part of the building design and less like a bolt-on afterthought.

Developers should take care when specifying roof integrated solar to make sure they get the aesthetics they’re looking for.  Since the silver framed panels are of fractionally lower cost, a specification that simply asks for ‘roof integrated solar’ could result in installers (driven by an enthusiastic Quantity Surveyor) pricing silver panels above a plastic sheet, which looks little better than the rack-mounted above roof systems.

A booklet published by the Solar Trade Association – Stunning Solar – showcases solar design and features many excellent examples of roof integrated solar, also check out this gallery of fabulous photographs of homes with integrated solar.

The UK solar industry has developed MCS012 testing to ensure that roof integrated solar systems comply with building regulations on wind resistance, weather tightness and external spread of flame.

New Approaches to Cost-Optimisation Have Emerged

House builders, architects and energy consultants have taken some time to figure out how to use solar in cost-optimised designs for homes.  Clearly the rapid cost reductions the technology has achieved has made it difficult to keep up, but in addition the price-performance curve for solar is quite different from other energy saving options.  Insulation follows a law of diminishing returns - the next improvement in energy saving needs more and more insulation.  In contrast, the bigger a solar system gets, the lower is its cost per kWp and the lower the cost of the CO2 savings it produces.

What this means for those aiming to design cost-optimised new homes is:

• A combination of solar and fabric (insulation) measures may be more cost effective than fabric alone.
• If your energy assessor suggests that your homes need a small solar system (perhaps less than 1kWp) , you should also take a look at the total cost of a larger solar system coupled to less extensive use of alternative energy saving features.

At Viridian Solar, we see that  more and more house builders, energy assessors and architects are pricing for a range of different sizes of solar system for their homes, suggesting that some in the housebuilding industry have already understood the opportunity to use larger solar installations to optimise total construction costs.

I have written in more detail on this point in this blog.

Reliable Performance has been Demonstrated

In recent years concerns have arisen in the construction industry about the energy ‘performance gap’.  This is the difference in energy efficiency calculated for a house design and its actual energy performance once it’s built.  Unfortunately on building sites in the real world, things happen that don’t appear on the CAD drawings of the architect and energy assessor.  Small openings around pipes let in drafts, gaps are left between insulation and windows are installed in a position to create a thermal bridge.

Solar has proven itself to deliver the energy savings predicted by the SAP calculations - and if anything to outperform the estimates.  An assessment of the energy yield of PV panels by Sheffield University found 98% of installed systems were working according to their specifications. 

Not only does solar PV deliver the saints it promises, it does so in an utterly reliable way.  When the Renewable Energy Consumer Code assessed the complaints received about solar between 2010 and 2014, it was less than 1% of all installations, and this covered a time period during which cuts to the Feed in Tariff had driven extraordinary levels of deployment in short bursts.

 You Need Less Roof Area for the Same Power

Solar cells have become more and more efficient, raising the power output of solar panels as they do so.  Consequently less and less of the roof is needed to provide a given annual energy yield.
In the last ten years the average power output of newly launched solar panels, measured in Watts-peak (Wp), has risen by between two and three percent every year.  In 2010 people were typically installing solar panels with a peak power of 220Wp.  In 2014 this had increased to 250Wp.  Solar panels with a power of 275Wp are now commonplace today and panels of 300Wp will soon be widely available.

Shading is Less of an Issue

Image: Viridian Solar

Shade is clearly not good for solar panel energy yields, but the availability of micro-inverter and power optimiser technologies means that the effect of partial shading on solar arrays can be minimised.  Power electronics is fitted at the level of the individual panel in such a way that if one panel is shaded it does not pull down the performance of the whole solar array.  Solar can now be fitted to roofs with complicated shapes that produce self-shading and into areas between dormer windows.

Customers Love Having it

According to Feed in Tariff statistics, there are now more than a 800,000 homes in the UK with solar, around 4% of all homes.  Most of which are people who have chosen to install solar as a home improvement.  Solar regularly comes out as the most popular form of energy in public attitude tracking surveys, with an approval rating over 80%.  Solar homeowners benefit from a ‘feel-good’ knowledge that a significant amount of their power use is provided from the solar panels on their own roof, visibly reducing their energy bills.

Evidence is also emerging that solar adds value to the homes that it is fitted to.  A survey by GoCompare found solar panels to be among the top ten home improvements in the UK.  Another recent survey by Barclays found solar was one of the top technologies that homebuyers want, increasing the value of a property by £2,000.  An authoritative study in the US discovered an average sales premium of $4,000 for homes for every kilo-watt peak of solar PV the house was fitted with.

Electric Vehicles and Battery Storage are on the Charge

Image: Tesla Motors

Electric vehicle registrations are growing at an extremely fast pace albeit from a low base currently.  Many manufacturers are now committing to develop and launch whole ranges of electric vehicles in the coming years.  Battery storage technologies for static applications are also coming to the fore with a number of high-profile global corporations (Mercedes-Benz, Panasonic, Tesla) launching products aimed at residential customers.

Solar and battery storage is a perfect match, with excess daytime energy held for use in the evening or to provide transportation when required.

The way people use and think about energy is going to change and the speed of this transition is already catching out government and energy companies alike.

The home of the (near) future is going to generate its own power, store it for evening use, and provide a power hook-up for electric vehicles.  The UK fleet of electric vehicles will store excess power from the grid during sunny or windy periods and release the power back into the grid at times of peak demand. It won’t be long before a home without its own power generation, battery storage and a charging point for an electric vehicle is going to be as outdated as a home with an outdoor toilet at the end of the garden.


This article is based on work to produce this technical briefing for housebuilders by the Solar Trade Association.

In Praise of Small Things

Are we too Quick to Criticise Housebuilders for Small Solar Installations?

Those crazy housebuilding companies!   Imagine deciding to install solar on a new home, then only fitting a measly one or two panels!  It’s tick-box solar, a pointless waste of time.  What a shame!  What a missed opportunity!  Boooooo!  So goes the usual reaction from the solar industry.

For sure it is driven by ticking a box, achieving a target carbon emission level for the property and perhaps also achieving a site-wide planning target for renewable energy.  But so what if its small?  Is bigger always better?  Why is 4kWp the gold standard for a domestic solar installation?

I already feel that I’ve set myself quite a challenge, but I’m going to have a go at convincing you that there is something truly magnificent about these small-but-perfectly-formed solar installations.

Let’s start with self-consumption.  As I discovered while researching this topic for a talk at SEUK last year, (and wrote up in a blog here), even houses where people are at home during the daytime don’t use that much electricity when the solar is at a peak.  If it’s sunny at lunch time, people are sitting outside eating sandwiches, not arc-welding in the basement.  

Yes, you can shift some consumption, but there’s only so many clothes to wash.  Yes, you can dump your excess in a hot water tank, but you’re only saving the cost of gas heating in most cases.  Yes, you can charge an electric vehicle (unless you’ve driven it off to work).  And yes, of course you could put the excess in a battery for later.  But if you put a small system on a home it simply meets the base load.  In the homes I looked at data for, the base load was between 25 and 75 Wh/10 minute period.  Around 150 to 450W.  With a small system, everything you generate, you use.

And another thing.  Aesthetics.  Some roofs can take a 4kWp system, no trouble and still look great.  But it is a really quite big area to accommodate.  Other attempts to fit as much solar as possible on a roof are less successful.  Smaller homes, buildings with dormers or roof windows, these often look much better if a more compact and bijou solar system is installed.

The drive to 4kWp came from the Feed in Tariff banding, encouraging people to size for the greatest amount of subsidy they could get.  In this new low-FIT and soon-to-be post-FIT world we need to re-think what a solar installation has to be.  Small solar systems and lots of them can add up to a great deal of emissions reduction without stressing the grid.  Manor Solar is about to start installing Clearline fusion on new homes near Peterborough - it might only be 500Wp per house but there's 3,000 homes in the development - I make that 1.5MWp from one development.

Have I convinced you that small is beautiful?  Let me know what you think leave a comment below!

Fundamentally, if the solar industry wants house-builders and construction companies to use more solar, it should make the case for it, and do so in terms that are meaningful to the people we hope to convince.

Fortunately, solar has a great deal to offer the construction industry.  My next blog will look at this.

The Allowable Solutions Puppet Show

In a recent article Stephen Williams, a Lib Dem government minister at the Department of Communities and Local Government (DCLG), was reported to have protested that as far as the government's Zero Carbon Homes Policy was concerned:

"There is a view out there that we have "watered down" our ambitions, or that we are merely "puppets" of the development industry. These views are outdated and blinkered."

Unfortunately for Mr Williams, a recent consultation response published by his department seriously undermines these claims.

The Zero Carbon Hub is an independent body created by the government to help define and deliver the Zero Carbon Homes policy.  After gathering evidence and consulting with the construction industry the Hub proposed that Zero Carbon Homes policy should be broken down into three requirements for new homes and proposed levels for each:

1. A minimum level of thermal insulation (called Fabric Efficiency)
2. A maximum level of carbon dioxide emissions from the house itself (called Carbon Compliance)
3. The balance of carbon emissions to be 'offset' through carbon dioxide reducing measures paid for elsewhere (called Allowable Solutions)

Fabric efficiency means building cosy, draught-free homes, this level was set just a little beyond current (2013) building regulations.

Carbon compliance could be achieved by pushing the insulation further (towards passivhaus level), or by installing renewable energy equipment on the homes such as photovoltaic (PV) panels, solar water heating or heat pumps.

Allowable Solutions was intended to help get difficult buildings over the line, and could account for around 30% of the improvement.  It would involve the developer paying into a fund that delivered energy measures off-site (perhaps like building wind farms or energy upgrades of existing homes).  It was suggested that the price of the offsets should be set at a level that would encourage developers to achieve as much as possible through improvements to the actual homes being built.

DCLG's Allowable Solutions consultation contained a question (Question 1) asking whether the Zero Carbon Hub proposal should be taken forward, and the results were recently revealed in the consultation response.

Fully seventy percent of consultation respondents (93 responses) supported the Hub's proposal.  Of the thirty percent that did not, many argued that even higher levels of energy efficiency should be required due to advances in insulation and renewable energy technologies.

By contrast a majority of developers, (14 out of the 22 responses from developers) did not agree with the Hub's proposals and wanted lower standards of energy efficiency for new homes, and more of the carbon emissions to be deemed as 'offset' through the Allowable Solutions mechanism.

So what did DCLG decide? 

It went with the developers.  The current proposal completely drops the carbon compliance requirement and allows developers to build homes little improved over those built today. 

DCLG ignored a clear majority in the consultation and it ignored the advice of the independent organisation it had created to help it deliver this policy.

According to the Minister, it is outdated and blinkered to think him a mere "puppet" of the development industry. 

Make your own mind up.

Picking Through The Wreckage of Zero Carbon Homes

The policy that categorically does not do what it says on the tin

It all started out so well in those early years.  There was a sense of shared endeavour in the construction industry.  When, in 2006, the government announced that by 2016 all homes built in the UK would have zero net carbon emissions, no one thought it would be easy, but many in the industry were eager to rise to this inspirational challenge.

The concept was that we should stop building new homes that would only need to be upgraded later to be properly energy efficient. Building these homes fit for the future would stimulate a mass-market for energy efficiency measures and renewable energy technologies and result in tradespeople and designers developing skills that could be carried over into the upgrade of our existing stock of buildings.

Well, here we are in 2014 and how has it fared?

In the run up to the Queen’s Speech, Stephen Williams, a Liberal Democrat MP and minister at the Department of Communities and Local Government (DCLG), began briefing via the Lib Dem website that he’d ‘saved’ the Zero Carbon Homes (ZCH) policy from those nasty Tories.

From information in his article its possible to piece together how ZCH will work.  So let's peer through the smoke drifting around and have a look at the train wreck we’re left with.

It seems like all housing developers will have to build homes that are equivalent to the Code for Sustainable Homes level 4, which is only a 44% improvement on the so-called regulated carbon emissions of a 2006 home.

However, even this overstates the ‘achievement’.  As I have covered before in this blog, the definition of zero has been adjusted to include only regulated carbon emissions (those from heating and hard-wired lighting).  All energy used by plug in electrical appliances (white goods, gadgets, audio-visual) have been removed from consideration.

Add back in the average emissions from plug in electrical appliances and the picture is even less flattering.  The original vision of Zero Carbon Homes has been diluted to such an extent that the achievement of which Stephen Williams is so proud is that a home built in 2016 will be allowed to produce fully 71% of the carbon emissions of a home built in 2006.

The average energy bill for one of these ‘Zero Carbon’ homes will be similarly unimpressive.  I calculate that a 3 bed semi-detached ‘Zero Carbon’ home would have a combined energy bill of £800/year whereas one built to 2006 standards would have a combined energy bill of £1080/year.

The political sleight of hand that Mr Williams is using to justify his hyperbole was announced in the Queen’s Speech and is the creation of legislation to enable an element of ZCH called ‘Allowable Solutions’.   This could be better called ‘Buying Carbon Offsets’ because it means that instead of pushing the performance of the building itself from Code level 4 to Code level 5 (zero regulated carbon emissions), the developer can choose instead to pay into a government-managed fund.  What this fund will be used for is, as yet, undefined, but seems likely to be spent on upgrading existing buildings.

Allowable Solutions was first proposed as a means of helping more challenging homes (for example flats with limited roof area) make it over the line by allowing carbon offsetting for that difficult last little bit.  What was supposed to be the mint chocolate with the coffees has now become the main course of the meal, potentially accounting for 56% of the regulated emissions.

The circularity of this is mind-bending.  Instead of building efficient homes in the first place, we effectively collect a tax from the developer, leaving the house-buyer with largely unchanged energy bills and putting the money into a pot which may or may not at some unspecified future point be used to improve existing buildings.

The opportunities for double-counting the benefits are also clear.  It's hard to imagine ministers avoiding the temptation to take credit for both the new homes being zero carbon and for whatever measures the fund is spent on at the same time.

Furthermore, there is to be a provision for ‘small developments’ to be exempt from reaching Code 5.  Again, it is not yet clear what small means in this context, but Barbour ABI has estimated that if small means a development of 10 or more homes then around 10% of new homes would be exempted from the policy, whereas if developments of up to 50 homes were to be considered small, then this figure would be around a third of new homes.

Which Tin?

In his article, Stephen Williams says that Zero Carbon Homes “does exactly what it says on the tin”

This astonishing claim doesn’t even get close to passing the ‘reasonable person’ test.  Someone offered a home described as Zero Carbon would have a reasonable expectation that the carbon emissions from the home would be zero and energy bills would be extremely low.

After ten years of backtracking, what we’ve actually got is a policy where new homes will produce more than 70% of the emissions they started with, coupled to a carbon-tax that might apply to only 2/3 of new homes built, and energy bills for the house-holder reduced by only 30%.

This policy "does exactly what it says on the tin" only as long as the tin in question is labelled "Business as Usual for Property Developers"

DCLG has succumbed to the enticingly simple argument that a proper ZCH policy would impose higher costs on developers and slow the rate of new build, thus threatening the economic recovery. The reason this argument is bogus is that if build costs rise, then the price a property developer would be willing to pay for land will drop.  Building to higher standards simply reduces the wind-fall to the land owner.  The only time the burden of building to a higher performance falls to developers is when they have speculated that legislation will be watered down and over-paid for their land bank.

It is not clear that this “world-leading” policy even meets the wooly definition of the European Directive on the Energy Performance of Buildings that the UK must comply with by 2020.  This requires all housing to be ‘nearly zero carbon’.  It may be that this is tested in the European Commission, indeed a number of renewable energy associations are already considering just such a move.

All is not Lost

A properly designed structure for the Allowable Solutions might just get this train back on the rails.  The price per tonne of carbon should be set to encourage the use of now common on-site measures such as higher levels of thermal insulation, heat pumps, solar water heating and solar PV.

One opportunity would be to set the price per tonne in a tiered structure, with an increasing marginal cost.

Code 4 is a 44% reduction in the emissions compared to a 2006 home, leaving 56% emissions available to offset under Allowable Solutions.  What if the chunk from 44% to 72% was priced at £120 a tonne, and the chunk between 72% and 100% was priced at £30 a tonne. Developers would have a strong incentive to drive efficiency up towards the 72% level (broadly equivalent to the old 'carbon compliance' level) using improvements to the building.

A developer who built to business as usual (Code 4) and paid the entire carbon offset would have an average cost to bear of £75/tonne.  By contrast a developer that improved insulation levels or installed renewable energy on the homes to bring down emissions below 28% of 2006 levels could reduce their average cost of carbon offsets down to £30/tonne.

A policy designed like this would be responsive to a changing market. If the housing market continued to improve and government decided that landowners could bear more of the costs of the policy, then the relative width of the bands could be adjusted.

Come on Mr Williams, all is not yet lost. You've still got time to make the reality of Zero Carbon Homes match your rhetoric.

Infographic - Slow Progress on Low Energy Housing in UK

Zero Carbon Homes Hierarchy

The Trouble with Triangles

The governments Zero Carbon Homes (ZCH) policy was launched in 2007 with the aim of reducing the carbon emissions from new homes built in the UK to 'near zero'.  I've written in the past about how this policy has been successively watered down and why the argument put forward in support of 'easing the cost burden on house-builders' is fundamentally flawed.

Recently, however, I started to wonder about the way the proposed structure of the ZCH policy was presented.  No government pronouncement on ZCH is complete without a pictorial representation of the ZCH Hierarchy.

The misleading qualities of geometry?

This image, reproduced from the recent DCLG consultation on Allowable Solutions, is shown above.  I have carefully scaled the triangle from this document for reasons that will become apparent when you read on...

The base of the triangle represents the carbon emissions from a dwelling built to 2006 Building Regulations, and the top of the triangle represents the 'pinnacle of achievement' that is a Zero Carbon Home.  The layers of the triangle represent different parts of the proposed policy. 

Starting at the bottom, we have the Fabric Energy Efficiency Standard (FEES).  The idea is that developers should 'build-in' efficiency gains to the property first through higher levels of insulation, lower draughtiness and installing an efficient heating system.  Government plans to legislate a minimum standard the home must achieve with such measures.  This concept was recently implemented into Building Regulations for the first time in the 2013 version.

The next layer up the triangle  is called "Carbon Compliance".  It represents the reduction of carbon emissions on-site through the use of low and zero carbon technologies such as solar panels.  Government plans to set a minimum level of carbon reduction that must be achieved on site.

Finally, for that difficult to achieve 'last little bit' the developer can buy their way out of building the energy saving into the house and instead pay into a fund - details to be confirmed.

The shape of the triangle produces a reassuring impression that the heavy lifting is going to be done by measures actually on the property, and that only the last little bit will be simply 'bought'.

Hang on.  Let's have a look at the actual figures.  Government is favouring proposals from the Zero Carbon Hub.  In their report, "Fabric Energy Efficiency for Zero Carbon Homes", the proportion of carbon reduction from each type of measure can be derived from the figure on the last page.  I have tabulated the values below:

In every case, the bought-in Allowable Solutions represents the largest part of the savings.  If the Zero Carbon Triangle were to be re-drawn so that the area of each section represented their relative contributions, it would look very different.



How it ought to look

Of course, if developers use the Allowable Solutions mechanism then the energy bills for householders purchasing a so-called 'Zero Carbon' house will be much higher than if developers choose to meet the target wholly with fabric improvements and renewable energy on the building itself.

Let's at least not kid ourselves about how far away from delivering zero carbon on the ground we might be by accepting misleading graphics at face value.

A Million Missing Low Energy Homes

The "Housing Standards Review" is set to eliminate a crucially important driver for renewable energy uptake in the UK and the way the government has gone about it is an absolute disgrace.

Solar panels on new homes - soon to be a thing of the past?

In a recently launched consultation, the Department for Communities and Local Government (DCLG) has revealed its intention to halt a practice where local authorities can require property developers to build to an energy efficiency standard higher than the current building regulations or insist on renewable energy (the so-called Merton Rule).

The background to the Housing Standards Review is that there has been a proliferation of overlapping (and sometimes conflicting) technical standards created in recent years, and local authorities are imposing a variety of these on developers, creating an unnecessary regulatory burden.  

DCLG convened a series of working groups covering eight thematic areas, one of which was energy.  The Energy Working Group concluded that the government should scrap rules that allow local decisions on the energy efficiency of new construction and rely solely on the national Building Regulations to drive future improvements in new build housing.

The justification for this change is that the Building Regulations are ‘moving towards Zero Carbon Homes’ by 2016 so there’s no need to have these alternative requirements – you can’t get better than zero carbon, right? 

While this argument is superficially persuasive, as soon as you scratch the surface you quickly find otherwise – let's take a look at what’s been happening at DCLG since the ‘Greenest Government Ever’ came into power:

• New Social housing was intended to be at zero carbon by 2013, paving the way for the commercial developers to follow.  This was scrapped and social housing is now built to the same energy performance as commercial housing.
• The definition of a ‘Zero Carbon Home’ has been diluted so that electricity use from plug-in appliances is misleadingly not included, making it more like ‘30% Carbon Home’
• The 2013 building regulations are late and will not be implemented until well into 2014, allowing at least 100,000 homes to be built to a lower energy efficiency.
• These new regulations represent only a tiny (6%) improvement on the previous ones for energy efficiency, when a 50% improvement was required to have any realistic chance of delivering 30% Carbon Homes by 2016.
• The ‘Allowable Solutions’ consultation may allow developers to pay a tax instead of building genuinely low energy properties.

(See my earlier blog on progress towards Zero Carbon Homes here)

If you had a suspicious mind, you might suspect that DCLG held back on the spectacularly unambitious 2013 building regulations to allow the Housing Standards Review to reach its conclusions based on a belief in government intentions to actually deliver Zero Carbon Homes in 2016, a belief that would have been difficult to continue to hold once the 2013 regulations were revealed.

If you were also of a cynical disposition, you might predict that DCLG is going to announce that it will put back Zero Carbon Homes to 2019 (just keeping within the 2020 deadline in the EU Energy Performance of Buildings Directive), but only after leaving the 2016 target in place long enough to use it to justify killing off local rules for higher energy performance and renewable energy.

Houses are not built to new regulations immediately; it takes many years until granted planning permissions turn into completed homes.  If Zero Carbon Homes is delayed until 2019, it will be 2022 before large numbers of homes are built to this level of performance.  DCLG will have created a ‘Lost Decade’ and a million homes built with unnecessarily low energy efficiency.

Economics not your Strongest Suit?

The ‘Impact Assessment’ for the changes proposed in the consultation claims a net benefit to the economy of more than £0.5bn.  It is claimed that £93m would be saved over the next 10 years by abolishing the Code for Sustainable Homes and £195m from abolishing local targets for renewable energy.

So that’s around £30m a year.

To put this saving in context, have a look a the turnover and profit of just the top three commercial housebuilders in the UK:

 

Source: Barratt Homes plc, Taylor Wimpey plc, Persimmon Homes plc

The Impact Assessment claims that this £30m/year is the ‘net benefit to business’, but what it actually presents is the net benefit to property developers, who no longer have to pay for environmental technologies or renewable energy. 

An Impact Assessment should assess the benefit to the economy, not one favoured sector. 

The businesses that would have supplied environmental technologies to help these new homes outperform the Building Regulations will be adversely affected, but the Impact Assessment takes no account of this.  Nor does it attempt to estimate the cost of improving these low efficiency homes later on. 

The Impact Assessment in support of the proposal is flawed and should be repeated taking into account the net effect of the changes on the whole economy.

Not Helping Anyone…. Except Rich Landowners

If building regulations are clearly signalled in advance and consistently applied, then developers can decide how much to pay for land with certainty about their build costs.  So the only thing building to a higher environmental standard will do is slightly reduce the massive windfall that landowners get when they convince a local authority to allow them to sell to property developers.

Conversely, if building costs are reduced then developers, in a competitive market for building plots, will bid up the value of land to a point where their profit margins are maintained. 

I’ve already written about this, often overlooked issue here: 'Who Pays for Greener Homes?'

Surely this isn’t the government’s intention?  To hamper the development of a clean energy industry and land the country with extra costs for upgrading homes that could have been built to a higher standard of energy efficiency – all so that a few rich landowners get a bit richer.  Not this government, surely?

Whatever Joined up Government Looks Like, it Ain't This

At the same time that DCLG is busy paving the way for a million low-efficiency homes, another government department has to shell out taxpayers’ hard-earned money to financially support people in improving the energy efficiency of existing homes.

The Department of Energy and Climate Change (DECC) is spending your money trying to convince people to upgrade the energy performance of their homes.

And boy is it hard work.

It is simply much easier and cheaper to install energy efficiency into a new home as it’s built rather than doing it later once someone is living in it.  It’s ‘common sense’ isn’t it?  It’s so much simpler to do it properly the first time than have to come back and do it all again later.

Compare the cost of putting thicker insulation into the wall as its built with the cost of fixing more insulation to the outside of a building, rendering it, and re-setting all the windows.

Or the hassle of getting a rig into your garden to drill a bore hole for a ground source heat pump – knocking down walls, tearing up your beautiful lawn – compared to doing it when it’s already a building site.

Or the cost of replacing all your radiators, - suitable for a gas boiler, but not big enough for an air source heat pump - compared to installing suitable ones in the first place.

Consider the cost savings from installing solar panels in the roof at the same time as the scaffolding is there for the roofers to tile the roof.

You get the idea.

DECCs incentives such as the Feed in Tariff, Renewable Heat Incentive, and Green Deal need to be set at an even higher level than simply supporting the extra costs to overcome people’s aversion to turning their house upside down to do the improvements.  (So called barrier costs).

The lack of progress in driving up standards in new homes is going to cost the country more in the long run.

How to Fix This

A situation where each and every local authority makes up its own environmental targets is an unnecessary burden on developers.  In my own business, we’ve helped many house builders discharge local authority renewable energy requirements in all parts of the country, and while they are all similar they are also all ever-so slightly different.  There is definitely a case for simplification.

However, the Building Regulations are not providing a pace of improvement that is sufficient.  Nor is the Zero Carbon Homes ‘end point’ adequate – the definition is too weak and proposals to allow property developers to ‘buy’ their way to Zero Carbon will result in homes that are little improved over today's.

The Building Regulations are not some 'gold standard' for energy efficiency that it is impossible to improve upon, they are nothing more than a minimum standard, a lowest common denominator.  Local authorities should be encouraged to exceed this minimum standard  where is is viable, and the assessment of viability should be a local decision in keeping with the DCLG's own Localism Act.

The route to simplification is not for central government to impose a one-size fits all, lowest common denominator standard, but instead to provide a limited menu from which local people can choose.  Fortunately the hard work has already been done because this is a description of the system in Scotland.  Here the building regulations have a special section with a limited number of alternatives to the minimum standard (Bronze) so providing local choice and simplification of regulatory burden for developers at the same time.

See my earlier blog on what we can learn from sustainable construction in Scotland here.

Why not adopt or adapt this sensible Scottish idea for the rest of the UK?

UPDATE
How to make your views known to DCLG, with template email can be found here