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

Zaba12 schrieb:

@Bookstar How is your firewood consumption looking overall now?

Tomorrow I’m going to turn on the underfloor heating because the wood might only last until December, and we didn’t have any sun last week or expect any next week to warm the rooms by an extra 1-2 degrees. With the current temperature at -8°C (17.6°F) and several nights below freezing without sun during the day, the ground floor was at 22°C (72°F) and the upper floor at 19°C (66°F). The temperature shouldn’t go any lower now.

How much does it cost to heat with firewood for a month if you have to buy it instead of owning your own forest?

Snowy36 schrieb:

How much does it cost to heat with wood for a month if you have to buy it and don’t own a forest yourself?

85€ per cubic meter of hardwood cut to 25cm (10 inches)

Currently, we have saved over 100€ and still have about one month’s supply of wood, which we will use during the transition period.

However, this year won’t be representative of typical consumption, as we have made many adjustments.

07/12/19 Meter reading 0 kWh (move-in)
12/31/19 Meter reading 3,083 kWh
05/06/20 Meter reading 5,579 kWh (storage installation)
07/25/20 Meter reading 5,624 kWh
10/19/20 Meter reading 5,743 kWh
11/27/20 Meter reading 5,895 kWh

I think it’s quite clear that I really had to experiment a lot this year because, in my opinion, despite the photovoltaic system, my consumption was still too high.

Whether it was due to the heat pump, the electric car, or simply careless electricity use, I’ll have to evaluate next year.

Bookstar schrieb:

Yes, you were right, November saw a significant increase in demand. We had temperatures almost constantly below 0°C (32°F) during the second half of the month. We used 548 kWh in November, which, at an electricity price of $0.21 per kWh, equals $115. Definitely reasonable.

Last year, we used 660 kWh during the same period, and November was almost 1°C (1.8°F) warmer on average. Still, that’s a 17% reduction compared to last year.

COP was 3.8 during that time. Of course, there are systems that achieve over 4, and I’m aware that my setup isn’t top of the line. But at least I don’t have to be embarrassed anymore 😀. And it’s warm everywhere, at least 22.5°C (72.5°F), except the bedroom (18.5°C / 65°F).

I could probably lower the heating curve a bit more. I haven’t used the wood stove in the last few weeks out of laziness (need to prepare firewood first 😀). Also, the water temperature is set to 50°C (122°F), which leads to higher consumption.

But comfort is much more important to me, so I don’t mind if we use more energy 🙂

I’m honestly afraid to fiddle with the heat pump settings, so I’m trying the opposite approach. A 17% efficiency gain really adds up, so I definitely did the right thing.

@halmi, your heat pump is probably the best tuned here, so your 460 kWh don’t count 😎

Oh, and to complete the picture, including the photovoltaics, we consumed 4,795 kWh from July 21, 2019, to December 31, 2019. For 5 1/3 months, that’s clearly reasonable, although maybe a bit much with an electric car.

Zaba12 schrieb:

I'm really hesitant to tinker with the heat pump. So I'm trying a different approach. 17% efficiency adds up, so everything was done right.

@halmi your heat pump is probably one of the best tuned here. So your 460 kWh don’t count 😎

Also, to complete the picture, including the photovoltaic power, from July 21, 2019 to December 31, 2019, we consumed 4795 kWh. That’s clearly for 5 1/3 months, even though it’s a bit high due to the electric car.

Is there a discrimination officer here? :P

Can you see how much you have charged your car?

halmi schrieb:

Is there a discrimination officer here? :p

Can you see how much you loaded into your car?

No, unfortunately not. I estimate about 9 kWh on average per working day.

So, the heating has been on since yesterday. I really hope that our current high consumption is because the screed is still cold and everything needs to warm up first.

That said, the household usage wasn’t really typical either. My wife ran everything that could be used multiple times: washing machine, dryer, oven, stove, and so on.

Yesterday, on the first day, we used 28 kWh (kilowatt-hours), including household electricity. Over the past two weeks, the consumption without heating has been about 13 kWh. If the heat pump uses 10 kWh in the next three days, then that would be acceptable. Let’s see.