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What the EPC requirement means for people who want to install solar PV

Posted by Cathy Debenham on 19 March 2012 at 10:14 am

To claim the top rate of feed-in tariff from 1 April 2012 all buildings to which solar PV panels are mounted or wired must have an Energy Performance Certificate (EPC) of at least band D. As the average house in England and Wales doesn't quite make it into band D, this means that many people will have to improve the energy efficiency of their house or office to qualify for the tariff.

What is an EPC

Energy Performance Certificates measure how energy efficient a building is. It is compulsory to have one done if you are selling or renting out a property. Until now they have tended to been swept under the carpet by estate agents who see them as an irritating bit of red tape. Although, with energy bills on an upward trend, it makes sense to examine your EPC closely before buying or renting, as they are a good guide to how much the building will cost to run.

Going forward EPCs will get more and more of a high profile: now for eligibility to the feed-in tariff for solar PV, and later the software with which they are calculated will also inform the renewable heat incentive and the Green Deal.

Speaking at the Solar Power UK Roadshow, MCS committee member, and founder of Sundog Energy, Martin Cotterell explained that EPCs are derived from an assessment of fuel cost per m2. They are based on standard assumptions of occupancy rates and assumed heating and electricity usage. This means that they may not reflect the actual energy usage in a building, which will depend on the number of inhabitants and their behaviour.

If you think your EPC is wrong, read more about the action you can take here.

The EPC will give you an Energy Efficiency Rating score, and outline what measures you may take to improve the rating, and what they are likely to cost.

What the changes mean for people thinking of installing solar PV

If your building is already at EPC level D, then you don't have to do anything.

However, if it is lower that D you will need to bring it up to level D to claim the feed-in tariff. You must provide an EPC certificate of D or above, with your MCS certificate, to register the system in the FiTs scheme.

Depending on what score your building gets now, the installation of solar panels may be enough on their own to bring it up to D. The only way to find out is to put the data into the EPC software. It is based on complex algorithms, and is unwise to guesstimate what effect any measure will have on the score.

The rate of feed-in tariff for those with an EPC level D is 21p per kWh generated for systems of 4KW and less. Without, it will be just 9p per kW (to find out how the feed-in tariff works click here). This will have a significant impact on rate of return, so it is important to be really clear about what measures you need to achieve D before you sign any contracts for the installation of solar PV.

EPCs are issued by domestic energy assessors (DEAs). Solar installers can qualify as a DEA, or they can partner with one, to make sure your property will meet the requirements. However, there have been some rogue practitioners at the cheaper end of the EPC market doing drive-by assessments, so make sure that your DEA does a thorough inspection, as it's you who stands to lose most if your property does not reach the required standard.

More information about EPCs and solar electricity from YouGen

When is an EPC not required for solar feed-in tariff?

Can I get an EPC for my solar installation before I finish my renovation?

Solar electricity information page

Feed-in tariff information page

How to find the best energy efficiency advice and information for your home



If you have a question about anything in the above blog, please ask it in the comments section below.

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7 comments - read them below or add one


capybaraComment left on: 24 April 2012 at 5:02 pm

We recently had Solar PV installed and took a gamble on whether we would make a Band D. Our Bungalow was built in 1982 and fortunately had Cavity Wall insulation installed. We decided that we would upgrade to an A  rated Condensing  boiler before commissioning our EPC survey, knowing this would go a long way to help making the grade.Even with Double Glazing, Cavity Wall insulation, A wall mounted Thermostat, A rated condensing Boiler, Energy efficient lightbulbs and the correct thickness of loft insulation we still only made a D although in the upper score bracket and close to a C. I would advise anyone not to take a chance like we did and get a proper Assesment done before arranging a Solar PV quote.

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Linn Rafferty

Linn Rafferty from JTec Energy PerformanceComment left on: 18 April 2012 at 6:23 pm

Cathy, Robert,

on the face of it, the chicken barn may be exempt from the EPC requirement.  This is because process energy is not included in the EPC.  Process energy includes, for example, electricity used for cooling a beer cellar, for heating an industrial process, and presumably, for cooling chickens. 

However, there may be something you haven't mentioned about the chicken shed that brings it into the EPC requirement, so don't take my word for it.  You should have an accredited Non Domestic Energy Assessor (NDEA) check the premise for you. NDEAs are the people accredited to produce EPCs for non domestic premises, and they can recognise when a building is exempt. If it isn't, of course they can also do the EPC for you.

There is another blog on this website on this subject here if you want further reading ... 

Or you could go straight to Ofgem as Cathy suggests, but possibly getting a NDEA in will give you an answer more quickly! 

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Cathy Debenham

Cathy DebenhamComment left on: 16 April 2012 at 11:49 am

Hi Robert. You've got an interesting one there. Is there a difference between cooling for humans and cooling for animals I wonder? I suggest you go straight to Ofgem for advice on that one. And do let us know what response you get. 

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SolarBarn Ltd

SolarBarn LtdComment left on: 12 April 2012 at 9:22 am

We have a trickie EPC situation and wondered if any experts out there may have the answer:

Our potential client wants a 20kWp PV array on a hay barn.  The supply comes from an adjacent barn.  Neither building 'uses energy to condition the indoor climate' so are exempt from EPCs. So far, so good.

However, the barn with the supply also supplies a chicken shed that has fans for cooling.  The PV system is therefore connected, albeit indirectly, to a building that may be seen to have a conditioned climate. 

Does anyone know if such a chicken shed is exempt from an EPC, and on what basis?  Otherwise it seems the scheme may not qualify for full FiT.

Robert Flynn

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NorthGlosEPCComment left on: 2 April 2012 at 4:24 pm


Although the possible issue of rogue practitioners at the cheaper end of the EPC market is something to watch out for my real worry is the possibility of Solar PV installers doubling up as DEA's and/or applying pressure to DEA's to make sure a "D" rating is the outcome of the now required assessment. Both possible scenarios would not bode well for staying within the conflict of interest rules or a completely satisfactory and unbiased final outcome for the customer.

Only the other day I carried out my first EPC assessment for a Solar PV installation. I was commissioned by the solar installation company through a "panel" or internet agency (next time I hope they'll contact me directly). This installation company had what I thought a very sensible policy whereby they will only install PV where a property already achieves a "D" rating. Very little can go wrong with this approach.

However I was there at the same time as the Solar PV installation surveyor. It was clear that both the solar surveyor and even the customer were both a little concerned about achieving the required "D" rating. Fortunately there was no problem but I could see how things might have gone had my visit been a pre-installation estimate on an "iffy" property to determine if a "D" rating would be the final outcome post Solar PV installation. A much more difficult situation could have been the case had I been both a PV installer employee and a DEA, and very likely paid on commission, and only in the event of installation completion.

So with these possibilities in mind I'm firmly in favour of the DEA being completely independant. This has to be the best approach for all concerned if even the remote possibility of a problem is to be avoided down the line.

I also fully agree about your comment regarding the cost of an EPC. Your friend who got one completed for £40 probably won't be using that assessor again because a £40 fee as that assessor will eventually realise is unsustainable. As you know out of that comes the lodgment fee, insurance, traveling cost, equipment cost etc. The final hourly rate is better collecting shopping trollies from the car park at the local supermarket.

A realistic fee now has to be over £50 and probably nearer £60 bearing in mind the extra time required to comply with the latest assessment requirements (RdSap 9.91). Still a lot better than if you're selling or letting and you get your EPC through an estate or letting agent, they'll still take £100 plus VAT off you. And, still not too much if you're after Solar PV and you want peace of mind before £10k or so of your money is committed on the basis of FiT qualification.

Like you say using a local independant surveyor, commissioned directly by yourself, is the safest and most likely the cheapest way to do it. And perhaps most importantly any information you're given will be honest and independant because this assessor will not be trying to sell you anything.

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Linn Rafferty

Linn Rafferty from JTec Energy PerformanceComment left on: 31 March 2012 at 2:29 pm

Cathy, NorthGlosEPC,

You've given a very sensible warning about the possible results of working with one of the rogue practitioners at the cheaper end of the EPC market.

It is the PV buyer who stands to lose most if their property does not reach the required standard. Where audit picks up serious inaccuracy, the EPC must be re-issued, and this could result in a rating of D being downgraded to an E or worse.  We don't know how it will play out if an audit shows that the EPC of D or better was incorrect & the property is really an E...

I was recently asked by an acquaintance why EPCs were so expensive. I asked him how much he had paid, and he said £40. Now to me that is not expensive for what can easily be 3 hours work!  If you are offered an EPC assessment at such a low price, you should be suspicious about the quality and accuracy of the product.

Check out my website for more information about the benefits of using a local DEA.

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NorthGlosEPCComment left on: 20 March 2012 at 11:33 pm


I'm all in favour of the rule that a property must achieve an EPC "D" rating to qualify for the Solar PV feed in tariff. In fact if I had my way it would be a "D" rating before PV installation rather than a "D" rating that can include PV installation.

I've always argued that energy efficiency should come before renewables . Why? Well, Our objective is to make the biggest impact in Co2 reduction (and our energy bills) in the most cost effective way, and that is most cost effective way is through good insulation and efficeint heating systems.

Much more Co2 will be saved and energy costs reduced for each pound spent on insulation and upgrading to a modern heating system than for each pound spent on a renewable, PV included. So home energy efficiency should come first. It's the most sensible approach both environmentally and economically. In the longer term of course we'll need both efficient homes and renewables to get where we'll need to be.

Moving on to the actual EPC. You mention the possibility of these being supplied by Solar installers who qualifyto become energy assessors? Well, I can see that all going a bit wrong.

In the assessors code of conduct there is a section about conflict of interest. Sounds to me like any Solar PV installer doing DIY energy assessments will be walking very close to the line on conflict of interest.

You also mention rouge DEA's and drive by assessments? Perhaps in the early days, but now there is an EPC assessment audit procedure run by the accreditation schemes. The DEA has no idea which of their assessments will get audited and so to retain their license a far more professional and accurate approach is the order of the day. Sure mistakes still get made from time to time but nowadays "drive by assessments" are in the tiny minority, and any assessor operating this way will be on borrowed time, if there are any left at all.

My advice to anyone thinking about installing Solar PV is to first talk to a local energy assessor, if necessary get that loft insulation, cavity insulation, new boiler installed or whatever, and get your EPC showing a "D" rating (or if you're sensible even better) before even talking to a Solar PV installer. Nothing bar nothing can then go wrong.

Or you might let your Solar PV installer do it all, EPC as well, and in some cases find (where pressure to secure the sale gets the better of them) they get audited, get it wrong and the corrected EPC results in less than "D". No feed in tariff and £10,000 worth of Solar PV on your roof? Now of course to be fair the incidence of this will be very small, but it could happen (and what a mess everyone will be in)

Get your "D+" EPC first, get it directly from a local independant assessor, and everything is bound to work out.





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