Decision for a heat pump

Good day,

I am currently planning a new heating system in NRW and have received various offers.

At the moment, a gas heating system is installed, which will soon give up the ghost. The plan is to replace it with a heat pump.

The heat emission system is underfloor heating for 190 sqm over 2 levels and radiator heating for an outbuilding, about 40 sqm, which is usually heated very minimally (maintained between 4 and 8 °C approx. in winter).

In addition, there is a photovoltaic system in the size range of 10 KWP with the option for expansion in the future.

Currently, I have the following 5 cost estimates, which differ completely both technically and in terms of price.

(The prices always include VAT.)

As a layman, I naturally have little knowledge about this and therefore ask for advice on which offer is reasonable.

In addition, the various offered heat pumps contain different refrigerants: What should I pay attention to here?

And more generally: what would you advise me?

Which brand is the best? Which one is to be avoided?

Thank you very much in advance!

Best regards,
Lukas

1) Chofu with 16 KW (18,000 €)
(Installable this year)

CHOFU heat pump monoblock 16 Kw

Refrigerant: R32

Switching valve
35m pipe
35mm fittings 35mm
incl. connection materials installation

2) Bosch with 14.8 KW (26,400 €)
(installable next January)

BOSCH split heat pump SAS 13-2 ASE Split, 14.8 kW,
monovalent

Refrigerant: R410A

2x BOSCH remote control/room controller CR 10 H
BOSCH refrigerant line SAS 3/8'' and 5/8''
Floor bracket package for air/water heat pump
JUNKERS hot water switching valve 22-1 for heat pumps
Membrane expansion vessel 25l, silver max. 3 bar
FLAMCO Flexcon suspension frame type MB 3
Logafix cap ball valve MK 3/4"
XStream Vent-Clean (DN20) K22
Pump group UK 1", without pump
Pump group MK 1", without pump
BOSCH mixing module MM 200 for 2 heating circuits
2x Grundfos circulating pump Alpha1 25-60 180230V
2x Grundfos Alpha angle plug, 4m cable
Distributor bar for up to 3 heating circuits
BWT storage connection set 3/4" M KS 1267-34 M 6bar safety valve
Various pipe, fittings and connectors
Filling the system according to ÖNORM
Working time: installation and connection of the heat pump including accessories
Commissioning by factory service

3) IDM with 10 to 24 KW (45,000 €)
(installable next March)

Heat pump IDM AERO ALM 10-24 KW, modulating
Accessories AERO AL 10-24 (buffer storage etc.)

Refrigerant: R290

3 x large surface radiators
various material
Commissioning
Underfloor heating manifold
small material
working time

4) IDM with 8 to 17 KW (30,000 €)
(installable next December)

Heat pump IDM AERO SLM 6-17, with NAVIGATOR 2.0
Equipment variant HGL

Refrigerant: R410A

Commissioning
Room device for one heating circuit to the NAVIGATOR
EIB-KNX module
Air separator
Sludge separator with magnet
Refrigerant connecting lines length 5 m
Distributor for underfloor heating

5) Saunier Duval with 12 KW (25,000 €)
(installable this October)

Saunier Duval heat pump with 12 KW

Refrigerant: R410A

3 x large surface radiators
various material
Commissioning
Underfloor heating manifold
working time

Hello! Without really being able to address the individual devices, I do notice, however, that all the mentioned heat pumps are very large (kw) in size.

How large is the heating load of the building? How much has been consumed so far in the year? What is the insulation standard?

I cannot provide any values regarding insulation, except that the walls are very thick, there is very thick Styrofoam on the outside, the intermediate ceiling is thicker than usual, and the windows have triple glazing.

So far, the heating load calculations for the heat pump have always resulted in a value between 12 and 17 KW.

just for your information:

The current consumption is about 46000 kwh of gas. This is also due to an old, inefficient, and poorly adjusted gas boiler. Everyone has told me that I should be able to get by with about 32000 kwh.

The photovoltaic system currently has no battery storage.

The underfloor heating requires a supply temperature of about 40 degrees. However, the hot water tank (possibly via a buffer tank) should also be heated by the heat pump.

There are no other heating sources for the time being.

In a heating load calculation according to DIN12831, there is no range between 12kw and 17kw but a single value. If necessary, commission one yourself.

No precise conclusions about the power can be drawn from the consumption. It doesn't work with cars either.