Energy Performance Certificates (EPC)
To obtain the RHI payment you need the completed MCS form from the installer of your heating system and an up to date EPC. The EPC rating has some influence on the size of your RHI payment. But it does not truly reflect the actual efficiency in use which is what really counts.
My experience with a ground up restoration of a Cotswold Cottage was that the EPC rating system (a tick box exercise on a laptop by the inspector) is weighted against old buildings. We had a mix of refurb and new build. The exisiting walls were stone and two feet thick. We insulated these internally with Cellotex, behind plasterboard. The new build was clearly cavity wall with insulation. The rest of the work involved the ASHP, underfloor heating, double glazing and LED lighting. The resulting EPC rating was only D+. We missed a C rating for not also having solar PV. The 20 year payback period on the Solar PV was just too long to justify. The PV panels would wear out and be technologically obsolete long before then.
My house is far more energy efficient than those on a new housing estate nearby . They are still being connected to the gas grid and have a better EPC than mine. Sour grapes!
Grant Aerona HPID10 10kWh ASHP
The EPC system is a bit of a farce.
I'm aware of people who issue some EPC's without even visiting the property 🤣
There is a massaging of numbers that goes on to make reports look better/worse depending on what you need for RHI or other things and many aspects of insulation/build are "assumed" on reports as being there without actually confirming this is the case.
For me the most important aspect of a properties efficiency is air tightness - something that we rarely test in the UK. The air tightness test exposes bad construction. If all new homes/extensions had to pass an air tightness test you would soon see a large improvement in efficiency and reduced energy consumption.
Mitsubishi Ecodan 14kw ASHP + 500l Cylinder
Hi Mike and George
on the solar PV, fitting the most number of panels you can and getting a battery gives a payback of about 10 years. Solar PV panels last 25 years plus (guaranteed to be 80% efficient after that time. The panels don’t fail. But connectors can need replacement (high DC current). Inverters have to be replaced (although the solar edge ones are guaranteed 25 years too)
EPC does seem to be a bit of a game. My 20 year old bungalow was assessed as B. We had doubled loft insulation to 300mm. Triple glazed. Plugged drafts. New oil boiler. 4kW solar PV. It is just a continuous improvement of building fabric.
After the ASHP, I think a new front and back door will be next.
Daikin Altherma 3H HT 18kW ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and Hyundai Ioniq 5 P45 electric vehicles with Myenergi Zappi mk1 charger
Just has the EPC done to qualify for the RHI - Rating A, Score 93. W/m2 heating 34
This means we qualify for the RHI and also we will get the full RHI
Sounds good. You will be fine; we're a 60 D, 21073/2644 kWh for heating/HW and our ASHP seems to work well.
How did you work out W/m2 from the EPC?
I just came across this:
It claims that an ASHP makes an EPC rating worse than if the same property were heated with gas, because of the way the algorithm is set.
Is this true? Bonkers if so.
Grant Aerona HPID10 10kWh ASHP
Yes, I was told the same. The heat pump improves your energy efficiency but does not show in your energy costs. Apparently, the EPC calculation does not take HP efficiency into account when making the energy calculation. Someone with better knowledge might explain it better.
@mike-patrick, it’s true and it’s crazy. We found this out earlier this year in an interview and the various heat pump bodies are trying to get the SAP (Standard Assessment Procedure) amended. Apparently, and I don’t know how it works exactly, but you get docked something like 50 points when switching to a heat pump from a fossil fuel boiler and making those points up is virtually impossible so you drop down the EPC bands. Another head scratching system and policy flaw.
An article on heat pumps and EPCs. It explains the problem with some examples. It's a couple of years old but I don't think anything has changed.
They do need a complete rethink. My flat in london I sold 18mnths ago. Was electric only and terrible running costs (elvaco 1970's direct electric), all flats were an E. In the 12 months befre I moved out, I was hardly there (for personal reasosn) so energy bills were only 15 quid a mo.
The EPC assesor gave it a 'C'. The only C in the entire block. No Way is it a C. I just wasn't there or using heating which must have affected his reasoning.
Also of concern, the assesor was in the property 10s max. He looked at one heater, in one room then was off. Offered to show him round but he said he didnt need to see anything else apparently. Make of that what you will.
I have now received a reply from the Department for Energy Security and Net Zero via my MP, a copy of which I have attached.
If my interpretation of their reply is correct, to quote from the reply, "EPCs produce an energy efficiency rating (EER) based
on the estimated running costs of the property", which would indicate to me that running costs is of primary concern rather than energy efficiency. Maybe it should be renamed a Cost Performance Certificate (CPC) rather than an EPC.
So it would appear that in the department's present opinion, it is more cost effective to have a gas boiler than a heat pump. 🙄
In fairness the reply does go on to state that the Government is currently working on proposals for improving EPC metrics. I hope that you don't mind if I don't hold my breath.
I have now sent this followup message and look forward to their reply.
The heat pump improves your energy efficiency, but does not show in your energy costs.
I have not read any study about improvement in energy efficiency after heat pump upgrades under RHI scheme, but my cousin who lives in Australia experienced significant reduction in the energy costs. He got his electric resistance water heater upgraded to heat pump water heater under the state government scheme. I think the local climate and performance of the ASHP play a major role in this case.