ᐅ New Construction with a Heat Pump: Two Perspectives

Hello,
we are currently building a KfW 60 house, 133 sqm (1,433 sq ft) living area, with 16 cm (6 inches) concrete walls, 12 cm (5 inches) of expanded polystyrene insulation, and underfloor heating on the ground floor. Upstairs, there is drywall construction with 160 mm (6 inches) glass wool insulation and radiators.
The developer wants to install a 6 kW air-to-water heat pump, since the plot is too small for geothermal energy.
A heating company currently working with us would definitely install a 9 kW inverter heat pump to cover cold winters. The developer believes that 9 kW is too large, even as an inverter device.
We now have to make a quick decision and would appreciate some advice on what system to choose.
There is a heat load calculation available, but it is reportedly still on the developer’s desk.
Thanks, baupfusch

Hello,

baupfusch schrieb:
...and underfloor heating downstairs. Above, drywall construction with 160mm (6.3 inches) insulation glass wool and radiators...

The combination of underfloor heating and radiators is usually not very efficient. Especially if a heat pump is planned as the heat generator (HG).

baupfusch schrieb:
... The developer wants to install a 6 kW air-to-water heat pump. The plot is too small for geothermal energy...

There is usually enough space for a vertical ground probe! ;-)

baupfusch schrieb:
... There is apparently a heat calculation, but it’s with the developer in a desk drawer.

This already disqualifies a candidate ;-) A heat load calculation kept in a desk drawer is of little use, especially since they are often incorrect.
Furthermore, performance figures for air-source heat pumps, unlike other heat generators, are not very meaningful because heating capacity and COP can vary significantly with outdoor temperature.
Example:

Thanks, Baupfusch

Best regards