Solar heat pump - offers & little time

Hi!

I have already been active in the "Rosa-Forum" (as it is nicely called). However, you quickly encounter knowledgeable sellers and/or people who generally want to discourage you about the house very quickly. Here it is much more sympathetic, and here you are more likely to exchange ideas with people who have gone through the same situation as we are now – or are also in this situation -> the agony of choice. Without generally wanting to demonize the other forum...

We are currently in the situation that we are supposed to get an air-to-water heat pump installed in our house by the developer. Oh yes, our house: semi-detached house, KFW70, 145m² + basement, currently 2 people, in the future max. 4 people, required heating capacity; about 6 kW (heating load calculation is not yet detailed).

The credit from the developer amounts to 7,000 EUR + possible BAFA funding of 4,500 EUR would be a total of 11,500 EUR. An offer for drilling is already available, 6,300 EUR incl. VAT.

Now we are trying to decide on the "right" brine heat pump. Not an easy task, because opinions on various designs (product, buffer storage, ERR, etc.) differ greatly – and everyone claims this is the right way.

We currently have the following options:
- Tecalor TTF07 – 300l domestic hot water, 200l buffer storage
- Wolf BWS-1-06-I – 300l domestic hot water, 500l buffer storage
- Weishaupt (exact designation will be received tomorrow) – 300l domestic hot water, no buffer storage (-> underfloor heating)
- Junkers SUPRAECO STM 60-1 compact or STE 60-1 + water storage

Unfortunately, we don’t have much time left to decide, the developer is already putting some pressure. I think a decision should be made by the end of next week.

Many greetings & thanks for the effort!
Gatho

Think of the BAFA before you buy or sign anything!

Yes, thank you for the hint - we will do it that way.

Buffer tanks for the heating circuit should generally not be installed with underfloor heating. This has already been discussed here and in other forums several times (and mostly quite clearly). For domestic hot water, 300 liters should be sufficient.

I cannot tell you any more details about the devices. What does the heating engineer who is supposed to install the unit say? He should be familiar with the device. Usually, everyone has their favorites.

Good morning,

it's really unbelievable how different the opinions are among heating engineers. Some only do it with a buffer tank, and only one said that you should actually consider the underfloor heating as a buffer and that you don't need an additional buffer tank. Could you briefly explain again why buffer tanks are "poison" for a heat pump system and why many heating engineers still insist on installing them (apart from financial reasons!?).


Exactly, everyone has their favorites - but which favorites are recommended?

Yesterday we also visited someone who is very focused on gas condensing technology. The investment costs would be around 6,500 - 7,500 EUR (including installation, chimney, heating system), and with the subsidy for the air-water heat pump, there would be no additional cost. In this respect, I am not completely opposed. The 5,000 - 6,000 EUR extra cost for a ground-water heat pump first has to pay off compared to a gas condensing system.

Best regards
Gatho

Exactly, the underfloor heating is enough buffer. Why should you heat an additional buffer tank separately? What advantage do you expect from it?

Are you completely free in the choice of heating installer? Those who want to install an additional buffer (for the underfloor heating) would be out for me. Otherwise, let the heating installer install what they know best. How effective the heating is can be seen, among other things, from the values in the Bafa table.

The gas heating also includes the gas connection or the tank. Is that taken into account? At the same price, you can also stay with the air-water heat pump.