Heat pump for KfW55 house 148 sqm

2022-11-18 08:51:26

With us, electricity has risen from 28 cents to 39 cents. Gas has fallen from 16 cents to 15 cents per kwh.

Since the construction is just starting and we do not yet have a heat pump, I am of course willing to install a photovoltaic system, but the local solar installer is not responding.

2022-11-24 12:25:27

Dear heat pump experts and experienced home builders, I would like to be able to estimate what heat pump capacity we really need. Our project: 2 full floors No basement 148 sqm KFW55 Our energy demand calculation suggests a 6kW air-to-water heat pump. However, the heating load calculation shows an 8kW air-to-air heat pump in the plan. Both calculations are rather by the book, since it’s a property developer. Which information in both documents should I look at? 8kW seems very high to me, but that is only a gut feeling, which I have developed by reading here in the forum. The underfloor heating is already installed, also by the book, the screed has been resting for 4 weeks and is waiting to be heated up. But there is no heat pump yet. The property developer would credit us €15,000 if we take care of the heat pump and installation ourselves. All these questions overwhelm us. Is that even possible? Can you use a different model or company? Is it worth it, is €15,000 okay? Is 6kW enough?..... We need ammunition to confront the property developer. Help! Thanks!

Just let the property developer do it, better 2kW too much than too little!

2022-11-24 13:14:31

Just have BT done, better 2kW too much than too little!

Factually unfortunately wrong. A heat pump is rather undersized. Oversizing leads to efficiency losses (+ increased purchase costs).

2022-11-24 13:34:08

... and not rarely through clocking to increased material wear

2022-12-07 21:10:25

It can be even better.

In the conversation with the construction management today, it came out that an 11kW Daikin was ordered.
148 sqm
2 full floors
KFW55 standard

I can't believe it.

In the heat load calculation for AT reference location -12°C, a standard heat load of 5115W was calculated,
the norm heat load (including heating-up surcharge) is stated as 6233W.

How do you get to 11kW from that?
I can't make sense of it when studying the document.

That can't be right. I have no idea about the subject, but my gut feeling screams such a big NO!

Is it sensible to post the document here?

An engineering office for heat load calculations is always recommended here. Which one was it again?
I am thinking of commissioning a calculation there and then getting the suitable heat pump myself.
Who knows when the 11kW system will arrive, since it was only ordered in May 2022, and the heat load calculation is from February 22.

Thanks
Wärmepumpe.seeker
on the next karma level

2022-12-07 21:45:19

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

I tried it once, this was the result:

[ATTACH alt="Bildschirmfoto 2022-12-07 um 21.43.15.png" type="full"]76738[/ATTACH]

And I already heated up quite a bit with 24°C. We don't need it that warm, we're more the 21°C faction.

Wärmepumpe.seeker
at the next karma level

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Heat pump for KfW55 house 148 sqm

danielohondo

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