Heat Pump/Heat Curve question

You can always make a list of your energy using appliances (oven, kettle, etc etc ) and estimate how often you use them, multiply by their consumption and get a good idea of what your energy consumption is

There are also plug-in adapters that will measure the use of a single appliance if you want a more detailed idea
 
jpd said:
You can always make a list of your energy using appliances (oven, kettle, etc etc ) and estimate how often you use them, multiply by their consumption and get a good idea of what your energy consumption is

There are also plug-in adapters that will measure the use of a single appliance if you want a more detailed idea
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Or just read the meter periodically?
 
ArthurMcB said:
At least 1 similar house with just geothermal pump and bills are a lot lower.
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What's 'a lot lower'? They might have a smaller house, they might have a newer more efficient HP, they might have better control with their thermostats. Unless that house is an identical build then I wouldn't worry too much about it.

Before you change any settings, I would suggest the following:

- Buy a few wireless temperature sensors so that you can monitor the changes. I used Tapo sensors but that was just because I already had some TP-link stuff.

- Turn all zones on and all underfloor or rads to full flow, i.e. if you have TRV's, set them to the max. Basically the most efficient way to get heat into your home is to use every available inch of underfloor/radiator surface. It sounds a bit counter intuitive at first but it does make sense because it allows for the lowest flow temperature to be set

- Set all room/zone thermostats to the max, they need to be 'always on'. You don't want room stats turning off the heating while you are trying to find a natural sweet spot between indoor temperature and your heat curve.

- Don't set 'drop back' night time temperatures. Again it sounds counter intuitive but what happens is the heating system just turns off until it cools down. It then has to work harder to reheat the next day. Keeping the one temperature all day/night means you are very efficiently maintaining temperature and using cheaper night rate electricity

- A big saving can be found by reducing the temperature of your hot water cylinder. Dropping it down to 46-50°C will save a lot of electricity because your HP has to have a flow temp higher than what it is trying to heat and efficiency falls off rapidly at higher flow temperatures.

- And probably most importantly, don't adjust anything until the outdoor temperatures drop to 0-10°C. Its unusually mild for this time of year so you won't feel or notice the effects of changes to the curve until outdoor temperatures drop. Wait another few weeks and then drop the curve. Try not to change it more than once a day or even every 2nd day. You are trying to let the house settle to a comfortable temperature so fiddling with settings too often will mess with that.

Doing all of the above, we knocked ~20% off our heating usage and have a much more pleasant and consistent temperature throughout the house. But our house is smaller, has an air source HP and is all radiators (no underfloor)

Hopefully you can get a similar result and knock 1-2k units off your electricity
 
Thanks @_OkGo_ for taking the time and your detailed reply. Ill take your advice on board for sure and ill report back here with results etc. Thanks again.
 
Hi

I reduced my curve by a small amount. I didnt notice any affect on house warmth or water so i left it at that.

My bills have definitly reduced but i dont know if its due to this or due to me changing provider or due to the credits being applied.

I will look to reduce curve some more to see what effects but for now am content with bills given they have reduced.
 
Thanks for the quick reply.
Very frustrating heatpump to use and adjust. Mine is run off an external thermostat so going to see about getting one installed in the inside of the house.
Also I have mine on a timer so going to put in an full time for a day at reduced temp and compare usage.
 
Retrostan said:
Thanks for the quick reply.
Very frustrating heatpump to use and adjust. Mine is run off an external thermostat so going to see about getting one installed in the inside of the house.
Also I have mine on a timer so going to put in an full time for a day at reduced temp and compare usage.
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Mine is also run off ext thermostat. What make is yours? Mine is danfoss. Iv oft wondered would it be betfer to use an internal thermostat
 
You can set them up to use an internal temperature, but they will then be less efficient.
Meaning you will use more electricity and get higher bills.

Heat Pumps are a fabulous technology. The problem with them is that they are almost the opposite of gas/oil boilers. So the heat settings that intuitively feel right for a gas/oil boiler are wrong for a heat pump.

Customers really need to be trained on how to get the best out of their heat pumps. I found the Heat Geek videos on YouTube to be excellent for this.
 
A Typical approach for a gas boiler (assuming you are trying to save money) would be to turn it on once in the morning and once or twice in the evening, each time for 2 hours. The boiler fires up and uses a flow temperature of 60 to 80oC. At this temperature the boiler will quickly heat your house up. If you graph the internal temperature of the house it is swinging widely from 14C to 24C. To save extra money you turn rads off in unused rooms.

If you take the same approach for a heat pump, i.e. turn it off an on, and turn off rads in unused rooms, the net effect of this is that you will have to run the heat pump at high flow temperatures say 50 to 55C. The higher the flow temp that the heat pump runs at the lower the efficiency (specifically the lower the COP coefficient of performance). At 55C you might achieve a COP of say 2.5 (i.e. for every KWh of electricity you get 2.5KWh of heat) which sounds great but remember electricity is expensive compared to gas, so at a COP of 2.5 it will be expensive to run.

Heat pumps are designed to run low and slow, i.e. on most or all of the time at very low flow temperatures. So with the optimal setup (including running with weather compensation, not internal room temperature), you might be able to heat the same property with the heat pump on all/most the time running with flow temperatures as low as 25C. With these low flow temperatures you might achieve a COP of more than 4. Which will make it very cheap to run. If you graph the internal temperature of the house it is steady at 20C.

Hence it is counterintuitive, in order to save money you are leaving it on longer and leaving on rads in unused rooms and ignoring the internal room thermostat. All alien concepts to someone who is used to a gas boiler.

Again I recommend Heat Geek on YouTube, and also Urban Plumber on YouTube.
 
ArthurMcB said:
Mine is also run off ext thermostat. What make is yours? Mine is danfoss. Iv oft wondered would it be betfer to use an internal thermostat
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Mine is a thermia( think they are the same company?) Diplomat duo.
Did a test there timed Vs constant on and came out with the same figures but still need to tweak. Using 30kwh day and 16 night
 
@AJAM Thanks very much for your detailed and valuable response. Really appreciate it, ill digest it and see if i can apply to my pump/settings.
 
Retrostan said:
37 degrees @ 0 degrees outside, it's set at 40 degrees out of the box
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Would you mind confirming what the rest of your settings are set to?

Just moved into a house with the same boiler and finding it very warm, I can tell the boiler is using a lot of power from the solar inverter app so the bills are going to be massive.

Also the water in the showers isn’t super hot but perhaps this is a characteristic of the system, I’m coming from a house with a gas boiler it was very different

Thanks!
 
HPSauce said:
Would you mind confirming what the rest of your settings are set to?

Just moved into a house with the same boiler and finding it very warm, I can tell the boiler is using a lot of power from the solar inverter app so the bills are going to be massive.

Also the water in the showers isn’t super hot but perhaps this is a characteristic of the system, I’m coming from a house with a gas boiler it was very different

Thanks!
Click to expand...
Hot water shouldn't be any colder than a gas boiler, check what temp dwh is being heated to you want 48 degrees
 
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