Heat Pump - Is it working or is it just rubbish?

Olinda99

To benefit from no gas standing charge you have to obviously have the gas removed - is that normally done as part of the heat pump installation or do you have to arrange that done separately and if so how?

Exiled_Tyke

Olinda99 said:

To benefit from no gas standing charge you have to obviously have the gas removed - is that normally done as part of the heat pump installation or do you have to arrange that done separately and if so how?

Some suppliers charge quite a lot for this (hundreds in some case).  If Octopus install the ASHP then they will remove the meter for free.  

Exiled_Tyke

NedS said:

matt_drummer said:

<snip>

My COP is 5.2 and his is only 4.2, the heat pump has to work harder to recover the house temperature (it took 4 hours to get back to 21c), needs a higher flow temperature to do it, is less efficient and uses as much electricity as just leaving it it on at a lower output for longer.

Absolutely correct. Where his strategy may become more effective is with TOU tariffs rather than comparing flat rates. For example, we turn the heating off overnight between midnight and 4am (otherwise charged at 26.22p per kWh) and turn it back on at 4am where the rate is 12.86p per kWh for the next 3 hours. Overall we use less electricity as we've saved 4h of running. We do use a more for the first hour as the system comes back up to temp, but it's half price so that only enhances our savings. Overall there is no loss of comfort as we want the house cooler overnight to sleep, and by the time we get up, the house is back up to temp so it's a win-win.

I would appreciate a little advice/opinion on this matter.  Currently my heating shuts (by which I mean the thermostat is set to 17.5) at 10pm and then I have it come on again in the early hours on my cheap rate like you @NedS. But what I do next I"m not sure on.   Most of the time I only need the house to be warm in the morning and then again when I'm back from work.  So should I leave it on all day (at around 20 degrees) or get it going again a couple of hours before I due back?   

matelodave

this is quite a good description of how to use "set back". Rather than shutting the system off, it should be set back by a couple of degrees to avoid the heatpump from having to flog it's heart out to restore the house temperature. 

https://www.grantuk.com/knowledge-hub/tips-advice/setback-controls-and-heat-pumps/#:~:text=Setback controls enable an air source heat pump,they help a heat pump to operate efficiently.

Reed_Richards

Exiled_Tyke said:

Currently my heating shuts (by which I mean the thermostat is set to 17.5) at 10pm and then I have it come on again in the early hours on my cheap rate like you @NedS. But what I do next I"m not sure on.   Most of the time I only need the house to be warm in the morning and then again when I'm back from work.  So should I leave it on all day (at around 20 degrees) or get it going again a couple of hours before I due back?   

Different heat pumps work in subtly different ways and you can operate the same heat pump in different ways to suit your preferences.  So I don't think there is a universal right answer.  The best I can suggest is that you alternate between a week one way and a week the other, look at how much energy you use in each week and hope for two weeks of similar outside temperatures that would enable you to make a fair comparison.  

Olinda99

Can anyone advise on the best way to set a heat pump when going away for an extended period in the winter?

I am assuming what you would do is just to set the room thermostat to say 14 degrees or whatever and leave everything else alone?

NedS

Exiled_Tyke said:

NedS said:

matt_drummer said:

<snip>

My COP is 5.2 and his is only 4.2, the heat pump has to work harder to recover the house temperature (it took 4 hours to get back to 21c), needs a higher flow temperature to do it, is less efficient and uses as much electricity as just leaving it it on at a lower output for longer.

Absolutely correct. Where his strategy may become more effective is with TOU tariffs rather than comparing flat rates. For example, we turn the heating off overnight between midnight and 4am (otherwise charged at 26.22p per kWh) and turn it back on at 4am where the rate is 12.86p per kWh for the next 3 hours. Overall we use less electricity as we've saved 4h of running. We do use a more for the first hour as the system comes back up to temp, but it's half price so that only enhances our savings. Overall there is no loss of comfort as we want the house cooler overnight to sleep, and by the time we get up, the house is back up to temp so it's a win-win.

I would appreciate a little advice/opinion on this matter.  Currently my heating shuts (by which I mean the thermostat is set to 17.5) at 10pm and then I have it come on again in the early hours on my cheap rate like you @NedS. But what I do next I"m not sure on.   Most of the time I only need the house to be warm in the morning and then again when I'm back from work.  So should I leave it on all day (at around 20 degrees) or get it going again a couple of hours before I due back?   

That's a really good question, and I don't know the answer. I think I would try running a few different options on similar weather days, record and compare to see which works best for you, with your system in your house. I have often wondered how those who are out (at work) all day transition from a gas boiler to the concept of always on heating

NedS

Olinda99 said:

Can anyone advise on the best way to set a heat pump when going away for an extended period in the winter?

I am assuming what you would do is just to set the room thermostat to say 14 degrees or whatever and leave everything else alone?

The most efficient way would be to set the flow temperature as low as possible and leave it running, but depending on the size of heat pump, heat loss of your house and outside temperatures, that may still provide more heat than you'd ideally like, so a room thermostat set like you say sounds a reasonable option. We also turn the DHW off whilst away.

One consideration - what anti-freeze protection do you have? Glycol or anti-freeze valves? If there is no adequate anti-freeze protection in place, then you will need to leave it running to prevent freezing of the outdoor system.

Patrol

Exiled_Tyke said:

I would appreciate a little advice/opinion on this matter.  Currently my heating shuts (by which I mean the thermostat is set to 17.5) at 10pm and then I have it come on again in the early hours on my cheap rate like you @NedS. But what I do next I"m not sure on.   Most of the time I only need the house to be warm in the morning and then again when I'm back from work.  So should I leave it on all day (at around 20 degrees) or get it going again a couple of hours before I due back?   

Does the manual mention anything. Suggesting as my GSHP manual suggests a maximum setback of 3 degrees to maintain efficiency

Exiled_Tyke

Patrol said:

Exiled_Tyke said:

I would appreciate a little advice/opinion on this matter.  Currently my heating shuts (by which I mean the thermostat is set to 17.5) at 10pm and then I have it come on again in the early hours on my cheap rate like you @NedS. But what I do next I"m not sure on.   Most of the time I only need the house to be warm in the morning and then again when I'm back from work.  So should I leave it on all day (at around 20 degrees) or get it going again a couple of hours before I due back?   

Does the manual mention anything. Suggesting as my GSHP manual suggests a maximum setback of 3 degrees to maintain efficiency

I haven't noticed anything but will have another look.  Thanks