Which heat pump? Ventilation system / Air-to-water heat pump

Oh, so with air-to-water heat pumps the numbers from the annual performance factor calculator are too good, but with ground-to-water heat pumps they are too bad? I see.

In the other forum, people easily achieve values over 4 with the Panasonic. The better the insulation, the higher the share of domestic hot water. This occurs all year round, so also in summer at 25 degrees outside temperature and 5 degrees ground temperature.

The differences in consumption are marginal, especially with good insulation.

First, I said nothing about the annual performance factor of the ground-source heat pump, second, it is not about THIS ONE Panasonic heat pump, third, an annual performance factor also depends on location, and the one user with the good performance factor might rather be the exception.
My ground temperature is 5 degrees in winter after long heating periods, significantly higher in summer (might be different with a limited borehole/collector). There is a website on the internet where people enter their real annual performance factors into a database, have a look at those of the air-to-water heat pumps there.

from on the go

I think most air-to-water heat pump owners are aware that they have a few hundred kWh higher consumption compared to a ground-source heat pump. That's what it comes down to, maybe 300-500 kWh. I'm not saying that an air-to-water heat pump is equivalent to a ground-source heat pump, but the principle is the same – you heat with electricity. The ground-source heat pump is slightly more efficient.

There are plenty of ground-source heat pumps in the database with a seasonal performance factor below 3. There are some air-to-water heat pumps with a seasonal performance factor above 4. It comes down to the fact that there are good and bad designs on both sides. On average, the difference is somewhere in the range of a few hundred kWh.

And you have to calculate 60-120 EUR extra cost per year versus initial investment of 6,000 to 10,000 EUR. It’s not worth it; much more worthwhile is a photovoltaic system combined with the air-to-water heat pump. Even 10-20% self-consumption and the ground-source heat pump is outdated again plus additional feed-in tariff. Of course, if you take it to the extreme then: passive house, photovoltaic system, ground-source heat pump. Everyone as they please.

With an air-to-water heat pump and a modern new build house, preferably KFW55 insulation and taking advantage of the 20-year loan term, no one will go broke. Yes, of course, a ground-source heat pump saves another 5-10 EUR per month.

One more thing about the database: you shouldn’t take it too seriously either. If no heating system with a low flow temperature is installed, then the seasonal performance factor also drops significantly, both for air-to-water heat pumps and ground-source heat pumps.

But as I said, technically optimal is probably the ground-source heat pump just like passive house standard, photovoltaic system, controlled residential ventilation with ground heat exchanger and photovoltaic battery plus e-car and photovoltaic on the garage (or even more ecological of course bike and public transport instead of a car at all). You can always take it further...

I consider 120 € per year to be very optimistic.. that would be only 10 € per month. At least in my circle of acquaintances, the monthly heating costs with the air-water heat pump are more like > 70 € per month. Generally, I agree with you - the choice of heating system is not that super relevant - one has higher investment, the other lower costs. At the end of the day, you end up similarly.

Can also confirm the numbers, 2 colleagues are in there. €900 per year with a brine-water heat pump and one family at €500 gas.

Can also confirm the numbers, 2 colleagues have that. €900 per year with ground source heat pump and one family at €500 gas.

The numbers say nothing, it depends on the size of the buildings, and on the electricity/gas price, as well as on user behavior (children/shower frequency etc etc). I pay less than €500 per year here with a ground source heat pump despite rather high electricity prices (rest of the info about my building project can be found here in the forum).

Goldi, that's nonsense... one kWh of heat from gas costs 7 cents - with one kWh from a brine-water heat pump with an annual performance factor of 4.5, it is about 5.5 cents without a heat pump tariff, with an air-water heat pump with an annual performance factor of - if you like - 3.8 it is 6.6 cents. Are you trying to tell me now that one kWh of heat from gas is twice as warm?