EPC rated air pump as "poor"

silverwhistle

Jemma01 said:

Would you mind sharing details about your solar panel installation and how much electricity it generates? Looking at the cost of the property from estimates given by the electricity supplier, it is 1.7k per annum, a lot of money for a 3 bedroom house with high insulation (overall EPC C/71)

I'm loathe to say what I use because everybody has such different circumstances: In the south, single and a low user, though I don't stint myself and have a wood burner which does most of the heavy lifting.

FWIW my electricity import including all my EV driving was 2900kWh and gas was 2200kWh. Gas was around £120 pa and electricty more difficult to estimate due to a change in tariff but probably about £450.

koru

Baxter100 said:

Performance data from a recent heat pump installation project:

Electrification of Heat - Interim Heat Pump Performance Data Analysis Report - Energy Systems Catapult



As you can see the SPF varies significantly depending on the individual installation. If you have the installation with the SPF of 4, great, you are matching a gas boiler.

If you've got the system with the efficiency of 2, not so much.

It is worth noting that this chart represents the efficiency of a sample of heat pumps that were in operation at the time of the report, so it includes heat pumps that are aged and do not include the latest technology. So, it may not represent the spread of possible outcomes for someone who is contemplating installing an ASHP in 2024.

The report does not segment the data by age of installation, but a proxy is to look at the chart just below this one in the report (sorry, I can't work out how to insert it here), which splits this data by type of refrigerant. Almost all of the low SPF figures are for heat pumps using R410A refrigerant, which is obsolescent and is being phased out in the UK. These are largely going to be older models. If you exclude these, the centre of mass of this chart would shift up by about 0.5 (judging by eye).

Also, this chart includes hybrid heat pumps, which tend to be less efficient.

The point still stands that not all new installations will get SPFs high enough that running costs are similar to gas assuming standard tariffs, but I think the chances are better than might be assumed from this graph.  

Spoonie_Turtle

koru said:

Baxter100 said:

Performance data from a recent heat pump installation project:

Electrification of Heat - Interim Heat Pump Performance Data Analysis Report - Energy Systems Catapult



As you can see the SPF varies significantly depending on the individual installation. If you have the installation with the SPF of 4, great, you are matching a gas boiler.

If you've got the system with the efficiency of 2, not so much.

It is worth noting that this chart represents the efficiency of a sample of heat pumps that were in operation at the time of the report, so it includes heat pumps that are aged and do not include the latest technology. So, it may not represent the spread of possible outcomes for someone who is contemplating installing an ASHP in 2024.

The report does not segment the data by age of installation, but a proxy is to look at the chart just below this one in the report (sorry, I can't work out how to insert it here), which splits this data by type of refrigerant. Almost all of the low SPF figures are for heat pumps using R410A refrigerant, which is obsolescent and is being phased out in the UK. These are largely going to be older models. If you exclude these, the centre of mass of this chart would shift up by about 0.5 (judging by eye).

Also, this chart includes hybrid heat pumps, which tend to be less efficient.

The point still stands that not all new installations will get SPFs high enough that running costs are similar to gas assuming standard tariffs, but I think the chances are better than might be assumed from this graph.  

For the OP it's definitely relevant, heat pump installed when the house was built in 2009.

Baxter100

koru said:

Baxter100 said:

Performance data from a recent heat pump installation project:

Electrification of Heat - Interim Heat Pump Performance Data Analysis Report - Energy Systems Catapult



As you can see the SPF varies significantly depending on the individual installation. If you have the installation with the SPF of 4, great, you are matching a gas boiler.

If you've got the system with the efficiency of 2, not so much.

It is worth noting that this chart represents the efficiency of a sample of heat pumps that were in operation at the time of the report, so it includes heat pumps that are aged and do not include the latest technology. So, it may not represent the spread of possible outcomes for someone who is contemplating installing an ASHP in 2024.

The report does not segment the data by age of installation, but a proxy is to look at the chart just below this one in the report (sorry, I can't work out how to insert it here), which splits this data by type of refrigerant. Almost all of the low SPF figures are for heat pumps using R410A refrigerant, which is obsolescent and is being phased out in the UK. These are largely going to be older models. If you exclude these, the centre of mass of this chart would shift up by about 0.5 (judging by eye).

Also, this chart includes hybrid heat pumps, which tend to be less efficient.

The point still stands that not all new installations will get SPFs high enough that running costs are similar to gas assuming standard tariffs, but I think the chances are better than might be assumed from this graph.  

I don't think that's correct. My understanding is that these heat pumps were all installed in the last 2-3 years as part of a funded government project, and the vast bulk of houses has their radiators upgraded as part of the installation (hence the low flow temperatures).

koru

Baxter100 said:

I don't think that's correct. My understanding is that these heat pumps were all installed in the last 2-3 years as part of a funded government project, and the vast bulk of houses has their radiators upgraded as part of the installation (hence the low flow temperatures).

I think you are right. The report isn't specific, but it does sound like these were recent installations.

However, on page 7 it does observe the difference in performance depending on refrigerant and it says "The R410a refrigerant is being phased out and therefore models of heat pump using R410a are likely to be older than those using R290 and R32. These older units may have less efficient mechanical components and control strategies." So, these were recently installed, but were obsolescent, inefficient models.

So, my conclusion is right, albeit for different reasons than the one I gave. That is, it does seem to be the case that the SCOP probability distribution for people installing now is significantly better, as they are unlikely to be offered R410a models (and can turn them down if they are offered). Indeed, they ought to turn them down anyway, because R410a is much more damaging to global warming if it leaks out of the device.

Patrol

Jemma01 said:

What detailed questions should I be asking the seller to help me form an opinion? How do I determine if it is efficient or not, and whether or not it heats up the water well and warms up the rooms?

I'd ask the seller if they have meter readings e.g. at date of installation and later, or on bills from say Jan 2023 and Jan 2024 so you can see how many units a year are used. You can't tell how much of that will be for the heat pump but it might give you a ballpark cost

Plus what temperature they keep the house at, if the heat pump is on a timer or set to run whenever required, if the house + water are warm enough and if they're happy with the system

I'd be happy to answer those sort of questions if it helped sell a house, and I'd prefer to see actual consumption figures over an assessment