EPC improvements – True or False?

Best would be to find an Assessor, tell him what you are doing and negotiate a deal that he comes to assess with the intention of the improvements and see what his calculator comes up with. At the end of the day you want a C so get him to tell you what is needed for him to give you a C. Don't necessarily rely on just one though. They are seem different and sometimes give different results. He should be able to plug everything into his app and play some tunes on it.

So to answer both your questions..
1) Yes EPC will go down when you swap gas for a HP.
2) Yes condensation boiler will increase rating.

EPC is flawed…
https://www.elmhurstenergy.co.uk/blog/2022/07/04/why-does-my-epc-not-recommend-a-heat-pump/

As Jason says however, it depends what kind of boiler was there before.

What does the EPC say you should do to reach an EPC Rating C?

One of my properties had an EPC done in 2010. It stated the average EPC Rating was 60 (D).
I had a new one done this year and the apparently the average is still 60 (D).
So, the average hasn’t increased in 14 years?

Reply to the comment left by Cider Drinker at 14/10/2024 - 13:28
That's due to ever moving goalposts. They are desperate to keep the algorithm secret so we can actually challenge their magic numbers.

Reply to the comment left by Jason at 14/10/2024 - 13:05
Worth pointing out that it has not been an option to replace a gas boiler with a non condensing model since 2005 (with very limited exceptions).

So it comes down to when the boiler was last replaced - many if not most replacements happening now will be replacing high efficiency condensers with another condensing model.

A condensing model will have a 22mm plastic pipe for the condensate to drain away (possibly leading into a larger waste pipe if the pipe run is outside to prevent problems with freezing up in winter).

Have a read of this https://energysmartworld.co.uk/will-installing-a-heat-pump-increase-my-epc-rating/

I am an EPC assessor doing both residential and commercial EPCs.

For a commercial EPC such as a small hotel, care home, student dorms or similar, you would definitely see a huge improvement in EPC going from a gas boiler to a heat pump as commercial EPCs are rated on their nominal carbon emissions - with heat pumps being a large improvement over boilers in this regards.

For residential, it is hit and miss depending on a lot of variables such as which boiler, whether you are running it at a reduced circulation temperature (improves condensor / boiler efficiency), which exact model of boiler / heat pump, whether using radiators or under floor heating etc.

Residential EPCs are rated on the estimated comparative running cost of boiler versus heat pump so you might get a worse rating after installing a heat pump.

The EPC software is due for an upgrade very soon which will take into account things like battery energy storage which would enable a heat pump to be mostly run using off peak low cost electricity.

Maybe wait if you can for the new software to be in use then get your EPC assessor to assess the house as is, and then model changes using the software to ensure anything you are thinking of doing will deliver the improvements you are hoping for.

In simple terms, EPCs are based on cost per KW, and electricity per KW is about four times gas per KW, and CO2 emissions have no bearing on them. So if you replace gas heating with an electric heat pump your EPC rating will drop.

So, as you might expect, Red Ed and Nut Zero Zealots don't know what they're doing, but this won't stop them doing it, all the same