Solar heat pump / what to watch for in the offer (single-family house, new construction, KFW70)

Hello,

...
1. Is this combination really sensible? ...

It can well be, but it depends on the specific data of the preliminary assessment. For heat pumps, the yield of the source is always decisive. This must be designed according to the actual demand (line, energy) for heating and hot water. Under-dimensioning usually leads to a money pit!
Likewise, on the heating side, sufficient dimensioning is necessary (heating load, room heating loads, heating surfaces, hydraulics)!

...
3. Which combination would be the most sensible from your point of view (i.e. size of the buffer storage etc.)...

For well-planned systems, a buffer storage is usually not necessary on the heating side!
The size of the hot water storage depends, in alternative, bivalent supply with a brine heat pump (hot water priority), on its performance and the load profile of the user!

Regards

Who can I ask if I want to have my heating system checked by my GÜ before installation?

I just want to make sure that no rubbish is installed. With or without buffer storage, ....

Who can I ask if I want to have my heating system checked by my GÜ before installation?...

You are welcome to contact me!

Best regards

Hello,

€uro is right - with well-planned systems, no buffer is necessary on the heating side. In your case, with a completely normal single-family house, this must be feasible.

185l domestic hot water storage can be little. How many people are you?

We have 250l - and here exactly 4 people can shower - but not 10 minutes each...
With a smaller storage tank, the heat pump would have to heat the hot water more often.
With 250l it is sufficient for us to prepare the hot water once a day.

Regards

Hi everyone,

thank you very much for the numerous replies. 185l is integrated within the heat pump. We are currently 2 people and both are employed from morning until evening. "Eventually" maybe a child will be added.

Before you focus on the heat pump, please first check the offer for the underfloor heating. Crucial for the "success" of your heat pump is as small a pipe spacing as possible. Maximum 12 cm, better 10 cm or less. This is something house providers like to save on. The smaller the spacing, the lower your supply temperature, the better the efficiency of the heat pump.

A brine geothermal heat pump with a COP of 4.7 is assumed (integrated hot water storage of 185L)

The specified COP is theoretical, as it primarily depends on the installed heating system, brine, and peripherals. The difference between heat pump types is likely less significant.

185 liters of hot water is rather sparse. 185 liters does not mean you have 185 liters of hot water available. The drawn water is constantly replenished with cold water, and after you have taken out 80 liters, the temperature is noticeably lower. I think 300 liters should be the minimum. If you want to indulge in a somewhat larger bathtub, even more is fine.

Additionally, a buffer tank, presumably between 200 - 300 L, is to be installed.
This is very often installed by heating contractors as a safety margin and to mask faults. In terms of effectiveness and energy consumption, it is complete nonsense. If you expect your heating system to be installed and from then on only have to adjust the room thermostat, you need the buffer tank. If you are willing to engage more closely with the subject and adjust settings and parameters repeatedly during the first year, you can do without the buffer tank and will be rewarded with lower consumption.

2. What should generally be paid attention to with heat pumps? I would definitely have a heat meter and a separate electricity meter installed. What else should be considered?

A heat meter is not absolutely necessary but very helpful for analysis. You will probably get a separate electricity meter anyway, as many utilities offer a special heat pump tariff. Based on extremely bad experience, I would choose the manufacturer according to customer service.