ᐅ Gas or air-to-water heat pump. Requesting assistance.

Hello,

We have been researching heating systems online for a long time.
We are getting desperate and hope you can help me.
We are building a single-family house in Berlin Mahlsdorf.
125 m² (1,345 sq ft).
It is a 30 cm (12 inch) masonry wall (including insulation) built with Ytong system prefabricated panels.
Completely with underfloor heating and no basement.
Gable roof.
I once did a quick heating load calculation online, which was about 8.6 kW (realistic).

The builder has provided an offer for a gas condensing boiler with heat recovery.

A cost-neutral offer for an air-to-water heat pump from Thermia Atec Total 9.

With the air-to-water heat pump, we would also save on the gas connection, and we would receive a credit of 2,500 for the heat recovery.

Please help me with the decision.
If you need more details, please let me know which ones. Thank you in advance.

125 sqm (approximately 1345 sq ft) new build with an 8.6 kW heating load!?

An air-to-water heat pump is acceptable with a price advantage of €4500 — I assume that means the VAT is waived, correct?

Is the heating load too low? I calculated it using an online calculator.

Well, the cost advantage with a heat pump would be around 2,000.

What does ST mean?

Thanks for the quick reply.

The heating load is way too high. For a larger area and a basement built to kfw70 standard, which is now common, I have about 4kW heating load (including hot water), location NRW.

Hello,

pb1989 schrieb:

It is a 30 cm (12 inches) masonry wall (including insulation) built with Ytong... prefabricated system components. Completely with underfloor heating, no basement.

30 cm (12 inches) - are you joking with us...?

pb1989 schrieb:

I once did a quick heating load calculation online, it was 8.6 (realistic)

Are you an energy expert, or what makes you think you could calculate the heating load...?

pb1989 schrieb:

We received an offer from the home builder for a gas condensing boiler with heat recovery.

There is no such thing as a gas condensing boiler with heat recovery, but there is a mechanical ventilation system with heat recovery!

pb1989 schrieb:

Please help me decide...

Stop trying to educate yourself on the internet and get professional advice... of course that costs some money. Is there no budget for that in your loan: buy a condominium.

By the way: it would be helpful if you follow the registration rules! Please enter your occupation!

Regards, Bauexperte

Somehow, every second thread here is about this. I have read a lot on the internet but haven’t managed to find any useful information in this forum.

Why don’t people just seek advice from the professionals?