Possible to exceed potential EPC rating?

anon_ymous

Hey

Just wondering if it is ever possible to exceed the potential EPC rating on a house?

I'm buying a house which is already EPC C which is decent enough, and it has potential to be EPC B, but I was wondering two things

- How I would improve the EPC to a B
- If it's possible to actually exceed what they say is potentially possible , and have it at an A? 

Verdigris

You could follow the recommendations on the EPC as to how you can improve the rating. I wouldn't recommend it though, because they tend to recommend things like fitting a wind turbine, but don't suggest solar PV. They do recommend solar water heating but it is much more expensive, £/kWh, than PV is isn't very versatile. They don't recommend heat pumps, despite the government wishing to encourage their use.

In short, EPCs are not fit for purpose but, unfortunately, you have to have one.

anon_ymous

Verdigris said:

You could follow the recommendations on the EPC as to how you can improve the rating. I wouldn't recommend it though, because they tend to recommend things like fitting a wind turbine, but don't suggest solar PV. They do recommend solar water heating but it is much more expensive, £/kWh, than PV is isn't very versatile. They don't recommend heat pumps, despite the government wishing to encourage their use.

In short, EPCs are not fit for purpose but, unfortunately, you have to have one.

It's quite weird that they don't encourage heat pumps. Is it due to the cost and size?

I'm also guessing over time they'll go down in size? 

ProDave

I built a new house and had a full SAP as built EPC (not the guestimate RDSAP of a used house)  So you would think it would be accurate, it had all the information about insulation and air tight levels in full detail.

It still managed to estimate my heating energy usage 3 times higher than it actually is.  My SAP gave a final score of A94, I wonder just how high it would be if instead of the estimated heating use you could input the actual metered energy use instead.

So agree with above, they are nothing more than a guide.

Verdigris

Another favourite recommendation is to replace an uninsulated concrete floor; cost estimate £5-10,000 say, saving £15 a year. And that doesn't take into account the enormous upheaval and the amount of embedded carbon in the new concrete. Doesn't make sense from a monetary or emissions basis.

Make sure you have LED bulbs everywhere. That can bump you up a good chunk for less than £50. Insulation is the other key improvement. Make sure you have good eveidence of any non-visible insulation, otherwise they'll ignore it and just make a standard assumption.

Phlik

waqasahmed said:

Verdigris said:

You could follow the recommendations on the EPC as to how you can improve the rating. I wouldn't recommend it though, because they tend to recommend things like fitting a wind turbine, but don't suggest solar PV. They do recommend solar water heating but it is much more expensive, £/kWh, than PV is isn't very versatile. They don't recommend heat pumps, despite the government wishing to encourage their use.

In short, EPCs are not fit for purpose but, unfortunately, you have to have one.

It's quite weird that they don't encourage heat pumps. Is it due to the cost and size?

I'm also guessing over time they'll go down in size? 

Heat pumps are more likely to make the EPC rating worse. They aren't cheap to run and like for like gas central heating is noticeably cheaper to run.
Heat pumps are are being pushed on the fact they are greener not cheaper.

Verdigris

They aren't cheap to run and like for like gas central heating is noticeably cheaper to run.

At April cap gas prices a heat pump returning a COP of 4 will cost the same as gas per kWh of heat. Also bear in mind that a gas boiler system has to be properly set up to get the claimed efficiencies; many aren't.

It is likely the price of gas will increase faster than the price of electricity so, in time, heat pumps will be cheaper and greener than gas.

Phlik

Verdigris said:

They aren't cheap to run and like for like gas central heating is noticeably cheaper to run.

At April cap gas prices a heat pump returning a COP of 4 will cost the same as gas per kWh of heat. Also bear in mind that a gas boiler system has to be properly set up to get the claimed efficiencies; many aren't.

It is likely the price of gas will increase faster than the price of electricity so, in time, heat pumps will be cheaper and greener than gas.

The cop drops the colder it gets outside, once you start getting towards 0 °C and below it's closer to 2. They're a good alternative to heating oil or bottled gas but they've got a way to go yet before they're cheaper to run than a gch system.

Comparing a well setup ashp to a poorly configured gch system is cheating

[Deleted User]

waqasahmed said:

Hey

Just wondering if it is ever possible to exceed the potential EPC rating on a house?

I'm buying a house which is already EPC C which is decent enough, and it has potential to be EPC B, but I was wondering two things

- How I would improve the EPC to a B
- If it's possible to actually exceed what they say is potentially possible , and have it at an A? 

I had a SAP-based EPC on a new build a couple of years ago and PV solar and PV thermal were on the list to get the property up to EPC A. For older properties, the EPC might list things like a new boiler, underfloor insulation etc. Whether what has been suggested is financially worth doing is separate issue.

The problem with EPCs is that the assessment is tick box based using a BRE database. For example, you could fill the loft space with a metre of sheep’ wool and you would get little if any additional credit above what it says in the BRE database. For example, not all heating controls have been tested by BRE.

Verdigris

The cop drops the colder it gets outside, once you start getting towards 0 °C and below it's closer to 2.

The COP for a system with a flow temperature of 35 degrees is 3.9, at 0 degrees ambient, for GSHP, and 3.5 for ASHP. Obviously it depends on location but the days when the ambient temperature is below 5 degrees are pretty few in most parts of the UK. I think a annual average of COP 4 is quite reasonable for a properly set up system. Sadly heat pumps have got a bad rep because systems haven't been designed/set-up properly.

Comparing a well setup ashp to a poorly configured gch system is cheating.

Indeed. But I'd wager the percentage of the population, who have a condensing boiler, that know the return temperature of their system is less than 0.1%!

anon_ymous

Verdigris said:

The cop drops the colder it gets outside, once you start getting towards 0 °C and below it's closer to 2.

The COP for a system with a flow temperature of 35 degrees is 3.9, at 0 degrees ambient, for GSHP, and 3.5 for ASHP. Obviously it depends on location but the days when the ambient temperature is below 5 degrees are pretty few in most parts of the UK. I think a annual average of COP 4 is quite reasonable for a properly set up system. Sadly heat pumps have got a bad rep because systems haven't been designed/set-up properly.

Comparing a well setup ashp to a poorly configured gch system is cheating.

Indeed. But I'd wager the percentage of the population, who have a condensing boiler, that know the return temperature of their system is less than 0.1%!

Would a micro chp boiler be any good? I'm definitely not going to put that in any time soon given that when the sellers put their house on the market, their boiler immediately broke which meant they had to put a brand new Vailant one in