Heat Pump EPC bad

thevilla

Reed_Richards said:

The_Green_Hornet said:

Reed_Richards said:

I think the 'Google' AI comment is another example of AS, "Artificial Stupidity" because it doesn't know the rules have changed.  At least I sincerely hope the rules have changed, we were certainly told it was going to happen. 

The new rules don't come into effect until 15th June with the introduction of RdSap 10.

EPC Changes June 2025: What You Need to Know

There you go!  These changes for the EPC assessment of heat pumps were announced two years ago, if I remember correctly.  And here we are in 2025 and still they haven't quite come into operation.  Given that the way heat pumps were assessed was totally wrong, I really do think this is a scandal.  But maybe I can now get a better EPC than @Screwdriva (on the Green & Ethical board) with his super-efficient gas boiler.  

I just took a peak and section 6.2 caught my eye.  Assessors will perform fewer assessments in a day yet travel expenses will increase!  How does that work? 😲

matelodave

thevilla said:

Reed_Richards said:

The_Green_Hornet said:

Reed_Richards said:

I think the 'Google' AI comment is another example of AS, "Artificial Stupidity" because it doesn't know the rules have changed.  At least I sincerely hope the rules have changed, we were certainly told it was going to happen. 

The new rules don't come into effect until 15th June with the introduction of RdSap 10.

EPC Changes June 2025: What You Need to Know

There you go!  These changes for the EPC assessment of heat pumps were announced two years ago, if I remember correctly.  And here we are in 2025 and still they haven't quite come into operation.  Given that the way heat pumps were assessed was totally wrong, I really do think this is a scandal.  But maybe I can now get a better EPC than @Screwdriva (on the Green & Ethical board) with his super-efficient gas boiler.  

I just took a peak and section 6.2 caught my eye.  Assessors will perform fewer assessments in a day yet travel expenses will increase!  How does that work? 😲

I also tried to work that one out but it defeated me 

NedS

matelodave said:

thevilla said:

Reed_Richards said:

The_Green_Hornet said:

Reed_Richards said:

I think the 'Google' AI comment is another example of AS, "Artificial Stupidity" because it doesn't know the rules have changed.  At least I sincerely hope the rules have changed, we were certainly told it was going to happen. 

The new rules don't come into effect until 15th June with the introduction of RdSap 10.

EPC Changes June 2025: What You Need to Know

There you go!  These changes for the EPC assessment of heat pumps were announced two years ago, if I remember correctly.  And here we are in 2025 and still they haven't quite come into operation.  Given that the way heat pumps were assessed was totally wrong, I really do think this is a scandal.  But maybe I can now get a better EPC than @Screwdriva (on the Green & Ethical board) with his super-efficient gas boiler.  

I just took a peak and section 6.2 caught my eye.  Assessors will perform fewer assessments in a day yet travel expenses will increase!  How does that work? 😲

I also tried to work that one out but it defeated me 

If I do a round trip route of 100 miles per day, but can now only conduct 5 assessments per day as they take twice as long, verses the 10 assessments I previously conducted, my average travel per assessment rises from 10 miles per assessment to 20 miles per assessment. I do not return to base after each assessment.

Travel expenses will likely decease overall (maybe now an 75 mile round trip round vs 100 miles before), but will increase on a per assessment basis. increasing the costs to perform each assessment.

akwexavante

I would be more bothered about how many walls are solid walls without a cavity and or cavity wall insulation or cladding.  Is it a listed building or in a conservation area?  Too many solid uninsulated walls and floors and poor loft insulation would suggest to me that the property DOES NOT best suit the installation of an ASHP to me.  I'd want to ask to see energy bills for January, Feb and march. The current owners have had one winter in the property, heated by an ASHP that perhaps should never have been installed in the first place.

Have they had a long, cold winter with a very high energy bill?

If it has a solid floor, i'd want to know how old the floor is and if it's insulated or not. 250mm of loft insulation is not enough.

I'd be more bothered as to why the property is being sold so soon after the currant owner purchased it.

Reed_Richards

The only property that does not "best suit" an ASHP is one that is so large and/or badly insulated that it is beyond the capacity of a single heat pump.  Heat pump ranges tend to have a maximum output of around 16 kW.  It's a myth that you need a well-insulated property for an ASHP but undeniably true that a poorly insulated property will be expensive to heat, whatever heat source you use.

For example, I replaced an oil boiler with a 12 kW ASHP.  The oil boiler cost me roughly £1000 per year to run at a time when the average cost of oil was around 50p per litre.  The price of oil is similar now so for someone paying £2000 or more per year for heating oil then it's likely they could not replace an oil boiler with a single heat pump.

ed110220

Reed_Richards said:

The only property that does not "best suit" an ASHP is one that is so large and/or badly insulated that it is beyond the capacity of a single heat pump.  Heat pump ranges tend to have a maximum output of around 16 kW.  It's a myth that you need a well-insulated property for an ASHP but undeniably true that a poorly insulated property will be expensive to heat, whatever heat source you use.

For example, I replaced an oil boiler with a 12 kW ASHP.  The oil boiler cost me roughly £1000 per year to run at a time when the average cost of oil was around 50p per litre.  The price of oil is similar now so for someone paying £2000 or more per year for heating oil then it's likely they could not replace an oil boiler with a single heat pump.

Isn't the grain of truth in this myth that air to water heat pumps have a lower flow temperature and therefore heat the house more slowly, so need to run for longer and are best used to maintain a reasonably constant temp? If you compare that with blasting a poorly insulated home with heat say in the morning and then again after work, between which it gets cold, then the amount of heating (and heat loss) will be higher. It's not an apples to apples comparison but I can see why it would be made.

akwexavante

My own thoughts are that a poorly insulated, not insulated at all property which i'm guessing this old country cottage will be, does not best suit the installation of an ASHP as a heating system.  To get the benefit of an ASHP the more, the better the insulation, the better the ASHP will perform.

Heat loss through the roof, walls and floors of an old insufficiently insulated building will be greater than the ASHP heating can cope with. It would have to work hard and therefore cost a lot of money to keep up and maintain a temperature, if at all.  It's possible that the ASHP cannot achieve the desired temperature the occupiers are wanting.

ASHP's are fantastic systems installed in the right building, a building with OOOOOoooodles of insulation to trap the heat generated for longer.

My gut feeling is that this cottage is probably poorly insulated and should have been insulated before an ASHP was fitted. It should probably not have been fitted in this building.

My gut feeling is that the currant owner / occupier has lived in the building for there first winter and they don't want to have to do it again. Cold cottage, high heating bill.

Martyn1981

ed110220 said:

Reed_Richards said:

The only property that does not "best suit" an ASHP is one that is so large and/or badly insulated that it is beyond the capacity of a single heat pump.  Heat pump ranges tend to have a maximum output of around 16 kW.  It's a myth that you need a well-insulated property for an ASHP but undeniably true that a poorly insulated property will be expensive to heat, whatever heat source you use.

For example, I replaced an oil boiler with a 12 kW ASHP.  The oil boiler cost me roughly £1000 per year to run at a time when the average cost of oil was around 50p per litre.  The price of oil is similar now so for someone paying £2000 or more per year for heating oil then it's likely they could not replace an oil boiler with a single heat pump.

Isn't the grain of truth in this myth that air to water heat pumps have a lower flow temperature and therefore heat the house more slowly, so need to run for longer and are best used to maintain a reasonably constant temp? If you compare that with blasting a poorly insulated home with heat say in the morning and then again after work, between which it gets cold, then the amount of heating (and heat loss) will be higher. It's not an apples to apples comparison but I can see why it would be made.

Yes I think what you are describing is possibly the 'reasonable' exception to what Reed Richards has explained, and to which I agree with him entirely.

But even that edge case can now be addressed with a HT (high temp) heatpump, designed to reach temps in the 60-80C range. Obviously these will be less efficient, with a lower COP, when running at higher temps, but should be comparable to a 'normal' HP when operating at lower temps for the less extreme heating months (Oct/Nov & Mch/Apr)?

HTHP's can also solve the issue of smallbore pipework, which may not allow enough flow rate during the coldest months for a 'normal' HP.

Of course, the best solution depending on finances, is to improve the property as much as possible, to reduce heating needs, and increase options.

QrizB

ed110220 said:

Isn't the grain of truth in this myth that air to water heat pumps have a lower flow temperature and therefore heat the house more slowly, so need to run for longer and are best used to maintain a reasonably constant temp? 

I don't think that's a great example either. Lower flow temps require larger radiators but if you can add 10kW to a space, it doesn't matter whether that's coming from an ASHP at 50C, a gas boiler at 85C or a solid fuel stove at 200C.

What is true is that generally, ASHPs are installed with lower maximum heat outputs than the gas boilers they replace, which means you don't have the capacity to "whack them up" and rapidly heat a space that has cooled below a comfortable temperature.

akwexavante said:

My own thoughts are that a poorly insulated, not insulated at all property which i'm guessing this old country cottage will be, does not best suit the installation of an ASHP as a heating system.

It depends what you're comparing it to, and what your expectations are.

Poorly insulated properties are generally expensive to heat, regardless of your heat source.

akwexavante said:

To get the benefit of an ASHP the more, the better the insulation, the better the ASHP will perform.

The performance of a heat pump - it's ability to move heat, and the COP achieved in doing so - is not directly affected by the insulation of the property being heated. What is affected is the amount of electricity required, and hence the cost. This is no different to a gas boiler etc.

akwexavante said:

 It's possible that the ASHP cannot achieve the desired temperature the occupiers are wanting.

This would only be true if the ASHP was undersized or poorly installed/operated. The same problems exist with other heat sources.

akwexavante said:

My gut feeling is that this cottage is probably poorly insulated and should have been insulated before an ASHP was fitted. It should probably not have been fitted in this building.

Undersized or poorly installed/operated, then?

You've shared a lot of thoughts and feelings but we have very few actual facts; the OPs property has an EPC that's typical of a heat pump EPC, and the current owner has recently fitted a heat pump. That's it. Everything else you've written is conjecture, coloured by some popular misconceptions about heat pumps.

NedS

Reed_Richards said:

The only property that does not "best suit" an ASHP is one that is so large and/or badly insulated that it is beyond the capacity of a single heat pump.  Heat pump ranges tend to have a maximum output of around 16 kW.  It's a myth that you need a well-insulated property for an ASHP but undeniably true that a poorly insulated property will be expensive to heat, whatever heat source you use.

I could not agree more. It infuriates me immensely when I hear Grant Shapps (and others) say his 3 bed semi isn't suitable for a heat pump. There is nothing special about a heat pump - it's just a heat source like any other heat source (gas or oil boiler) bolted on the end of a heating system that produces heat. 

Reed_Richards said:

For example, I replaced an oil boiler with a 12 kW ASHP.  The oil boiler cost me roughly £1000 per year to run at a time when the average cost of oil was around 50p per litre.  The price of oil is similar now so for someone paying £2000 or more per year for heating oil then it's likely they could not replace an oil boiler with a single heat pump.

This describes our house pretty well. We used to spend in the region of £900-1200 per year on oil depending on the price and severity of the winter weather, and we replaced it with a 12kW ASHP which cost us around £425 to run in the first year, so we have comfortably halved our heating costs and the house is more comfortable due to being at a more constant temperature in winter. I used to really struggle with the big swings in temperature from a massively oversized 24kW boiler controlled by an old fashioned Honeywell mechanical thermostat which gave a huge variation in room temp, so I find the constant consistent temperature from an ASHP much more comfortable.