Heat pump for KfW55 house 148 sqm

Thanks for the tip about the planning tool. I entered the data. It seems to result in a 6kW system (blue line), but the 8kW one is close, screenshots attached.

You can also calculate your heating load with another tool. Just Google "grabenkollektor Wärmepumpen verbrauchsdatenbank Energieeinsparverordnung heizlast". It’s also very close to the detailed calculation (from a group of DIYers).

I will do that too, just for fun, but it won't do us any good. Thank you

: Thanks for the pictures. The heating coils are in part already laid out very clearly. :rolleyes: The heating load is ONE thing. That means, what demand does the cabin have (including hot water), and how this energy is then supplied is another matter. Simply put. If, for example, there are only 20 m of underfloor heating in a room, logically a higher temperature must be used than with 40 m or even 60. Keyword VA.

And with the 6.2 kW, hot water is added as well.

I would rather take the "big" heat pump.

Thank you for the assessment. It also corresponds to my feeling, just all standard and ordinary. If we are not too far off with the 8kW, that’s fine. We then pay for the very manageable installation spacing with a higher flow temperature and thus higher electricity costs. But that will be the next chapter once the heat pump is in place and running.

If, for example, there are only 20 m of underfloor heating in a room, logically a higher temperature must be used than with 40 m or even 60.

But that has nothing to do with the heating load, as you yourself write. And whether an 8 kW (oversized) heat pump runs the flow at 35 degrees or the appropriate 5 or 6 kW heat pump does, it doesn’t matter. Both manage it – one more efficiently than the other (too large).

And please always remember that the heating load is calculated for -15 degrees or however low it may be. These days, if at all, are very, very rarely reached. Therefore, the heating load for a normal winter is significantly lower than stated in the calculation. That’s why you can calmly choose a small heat pump. In the end, it’s irrelevant for the original poster, since he will get the 8 kW one anyway.

higher supply temperature and thus higher electricity costs

Speaking of electricity costs:
Today received the future heat pump tariffs from the municipal utilities. :oops:

HT: 36.17 ct/kWh previously 23.52 ct/kWh --> 53.8% more expensive
NT: 30.20 ct/kWh previously 17.65 ct/kWh --> 71.7% more expensive
Basic price: from €108 p.a. to €114 p.a.

And the loyalty discount of 13% = 13 years has already been included.

In 2009, NT was at 9,x ct/kWh.

Annual requirement 2500 kWh-3000 kWh.