ᐅ Air-to-Water Heat Pump: Current Consumption and Data

driver55 schrieb:

How does that add up?
7.5 kW power consumption? 🤨

That can't really be right 😀

Probably 3 hours per cycle... not per day... right??

What?
No, of course not... that is the average over several weeks/months.
So, the average compressor runtime.

Just checked November: 1,165 kWh heating with 197 kWh electricity (ground source heat pump) for a 171 sqm (1,840 sq ft) KfW40 house in the very cold Hochsauerland region. This heating value was taken from the heat pump’s display, so it excludes domestic hot water and probably pump electricity.

Total electricity consumption of the house (including domestic hot water, ventilation, household electricity) was 406 kWh. In summer (with heating turned off) it was always about 200 kWh – the difference to the total November consumption is therefore 206 kWh, which fits well with the heat pump display reading.

I just realized that I somehow missed the meter reading for November 1st, so I can only provide the energy consumption for October and November combined.

~195 sqm (2100 sq ft), KFW55 standard, 2 adults and 2 small children, ground-source heat pump with borehole, controlled mechanical ventilation with heat recovery, western Germany / North Rhine-Westphalia. Indoor temperature 21.5 - 22.5 degrees Celsius (71.5 - 72.5 °F).

364 kWh electricity for 2065 kWh heat output (seasonal performance factor 5.67) for both months combined.

I expect the annual electricity consumption to be somewhere around 2200 to 2300 kWh.

[B]All figures include pumps and controls.

I’m particularly happy with the seasonal performance factor, which is a record so far. The building clearly has a generally low heat demand. However, the seasonal performance factor has not been that great for a ground-source heat pump in the past. I assume that the less efficient domestic hot water demand has a stronger impact on the seasonal performance factor in our case, simply because the heating demand portion is comparatively low. I’m very curious about December to see if these good consumption figures hold up.

I’m also glad to have fully insulated the house "all around" with EPS/XPS – not just the walls, but the entire floor slab is on XPS insulation, the flat roof is insulated as well, the parapet fully insulated, etc. – apart from the windows and a few minor wall penetrations, the building is practically free of thermal bridges. The low heat loss clearly demonstrates this.[/B]

guckuck2 schrieb:

Apart from the windows and a few wall penetrations, the building should practically be free of any thermal bridges. The low heat loss confirms this.

Yes, the external thermal insulation composite system (ETICS) is completely superior in this regard. My monolithic masonry is full of thermal bridges. As a result, the heat loss increases significantly.

guckuck2 schrieb:

I just realized that I somehow messed up the meter reading for November 1st, so I can only provide the combined consumption for October and November.

~195 sqm (2100 sq ft), KfW 55, 2 adults and 2 small children, ground-source heat pump with drilling, controlled mechanical ventilation with heat recovery, western Germany/NRW. Room temperature between 21.5 and 22.5 degrees Celsius (70.7 and 72.5 °F).

364 kWh electricity for 2065 kWh heat output (COP 5.67) for both months combined.

I expect the annual electricity consumption to be somewhere between 2200 and 2300 kWh.

All figures include pumps and controls.

So everyone, the year is over. How did your heat pumps perform in 2021?

Since my previous reading was off, I was at least able to gather data for December and, of course, for the entire year.

December
1659 kWh heat output (228 kWh of which was hot water) with 314 kWh electricity and a COP of 5.28 in December.
It was quite cold by our standards in December, although the same period last year was similar but with noticeably lower COP during the heating season. Either the small optimizations made over the past years really paid off, or the theory holds that there is still moisture locked in the building. Maybe both.

For the full year, total heat output was 10,532 kWh, of which 2707 kWh was used for hot water (~26% share).
Electricity consumption was 2407 kWh (previous year: 2439 kWh), at 0.195 €/kWh plus a fixed basic charge of €70 per year, totaling approximately €540 annually, or about €45 per month.
The annual performance factor (COP) was 4.375, which for a ground-source heat pump is still not outstanding but better than 4.21 the previous year. The trend is positive. I am not sure whether significantly better values would be achievable with the “simple” fixed-speed model used here, especially considering the 26% share of hot water.