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. 

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. 

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?

@kev-mit was on the EPC. Maybe its the new format?

I just came across this:

https://www.yorkshireenergysystems.co.uk/epcandheatpumps/

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.

Mike

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.

https://www.yorkshireenergysystems.co.uk/epcandheatpumps/

@mike-patrick - see https://www.elmhurstenergy.co.uk/why-does-my-epc-not-recommend-a-heat-pump  

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.