Heat Pump Running Costs

Yep I get that and I can see how it works when it's mild, not sure it's possible when it's very cold tho without dropping temp a lot?

I also run my HP at night only. My temp is set 23 and HP stops but it gets to 24 since UFH still gives heat. Rarely need radiators on upstairs since i keep bedrooms cooler. Mild days like these HP starts at 2 am at EV rate, colder days start at 11pm or 12am shuts down at 8am. I don't have fancy controls so scheduling is manual with changing options for timers but this needs to be only done few times during winter. Heating water temp is set to 45. I tried the leave it on and forget it option and found it was expensive especially on cold days when HP has to use backup heater to keep up with demand and this is expensive on day rate. My HP is old and tired but still works well with this setup.

Just trying to see if I am in the correct ball park?

597kwh for a for bed with converted attic about 150m2, A3 rated. No UFH.

January was much higher, over 780kwh.

To be honest I don't know how the heat pump is set up and how I have the thermometers set up. There are two zones, the downstairs and then the first floor and attic asking as one zone. The attic doesn't get used too much.

Are there some basic things I could do to brig down usage a bit?

We have a basic heatmiser control, nothing smart to it I don't think. It generally has two options, a Monday to Friday set up and an everyday set up. The Monday to Friday isn't very good as I work from home a bit and my wife could be off and have our son home for a day mid week.

I worry its heating the house the days all day but have put up with that as opposed to not heating the house as its a bit finicky setting the temp the night before based on who will be home etc. Is there a smart version of this I could upgrade to?

I amn't on a smart plan, more out of fear of them not being good value but I do get the sb smart data as I have a smart meter for 12 months now.

My average daily usage in summer was around 9kwh so I guess anything above that is for heating the house?

The coldest days in January were 37kwh. Its amazing how a couple of degrees can knock it up so much!

OK I'm going to call it…my heating has ramped down to where over the last week or so it has not come on. I even switched off the late night super cheap rate heating.

The changes I made this winter made have made a dramatic difference more than I thought myself. I looked back at Nov 2023 to March 2024 and compared to Nov '24 to March '25. TBH its a lot bigger saving than I expected where it cost me 42% less and I used 18% less energy….good result all around.

The daily cost chart though shows the difference. Average for 7 days and 30 days

I put the major saving was shifting to the Bord Gais EV rate back in October when I move to them …

I shifted as much of the DHW and heating into these 3 hours at night. My strategy was to pump as much heat into the house to build up thermal mass. I artificially set the temp stats to 22-23 degs to make sure the whole house was heated and all the zones were open. For heating this was about 8-10 kWh/night at 6.33 cent which is only 50-60 cent per night!!….it would be crazy not to use this rate. The house was nice and toasty in the morning and this lasted well into the day. I then put the heating on again at 7pm for 2 hours but at a more realistic setting of 20-21 degs. The aim again was to have as many zones open and if the HP is on then it needs to be heating the entire house.

My daily kWh doesn't show as dramatic reduction but as I mentioned my aim was cost reduction not necessarily energy reduction.

Any negatives….This strategy works only for a normal Irish winters day, when we had that really cold spell where it went down to -5c and didn't get above freezing even during the day, it didn't work and I had to put the heating on demand for those few days. But this was the exception and not normal weather.

I must also say I have a very well insulated house (A1) with underfloor heating upstairs and downstairs. I have good solar gain as well so this helped. Every house is different and you need to find what works for you.

But I must say not using those really cheap smart rates if you have a HP is criminal at this stage.

I got no complaint's either from her indoors or the kids that they were cold. The only complaint was in the last week or two the bedrooms were getting up to 21-22 degs as I was still pushing the heat in at night and the missus was saying she was too hot.. 😋

Finally for completeness here is the Monthly Heating Degree days for the last 2 years and although Nov 24 was mild, I dont think it was a particularly mild winter so that cant account for my savings.

Is it much cheaper to run a2w for cooling. Not sure can my daikin low temp split do it but if it was same usage as heating I wouldn't anyway. Like turning off hp in April except dhw until October.

Opening windows and patio door these days. Temp around 25 and bearable then wouldn't fancy using hp for cooling if it meant usage similar to winter.

Ya That's fair enough. Have nice breeze running through living area so not too bad tbh. Not sure can mine cool anyway.

General engineer or heating engineer?

I use mine for it and it pulls 500w or less most of the time. I definitely wouldn't class it as inefficient, and there was no additional cost to use it for cooling.