Combination of air-water heat pump + solar thermal + stove or only stove and air-water heat pump

Hello forum,

I am currently planning the new construction of a Kfw40 single-family house. The calculation by the expert yielded the following (short version): Heated building volume = 532cbm Building usable area = 170sqm Qp-new building = 29kWh/(sqm per year)

The offer from the construction company includes the following technology (where Kfw was only calculated with the heat pump): Novelan heat pump LAD 5 (air-water heat pump) Compact Station Dual 180l hot water tank + optional solar thermal SPE1 with 2 Roth collectors (2*2.52sqm) including 400l water storage tank. If the solar thermal system is installed, the 180l heat pump tank would probably be omitted.

I am basically aware that both systems are rather designed for the summer months and have their weaknesses in winter; nevertheless, the surcharge for the solar system (€4800) seems reasonable for ideological reasons... purely economically, it probably will never really pay off.

For the winter months, I am considering connecting the anyway planned water-bearing wood stove to the central water storage tank. For this, something like an MFS 600l multifunction storage tank from Novelan/Alpha Innotec would probably be required.

What do you think, all nonsense or somehow justifiable? Or just take the heat pump with a small water tank plus a normal stove for the living room (which is planned anyway)?

No ST - not at all for 5 k€ o_O, no water-bearing stove - for the ecological conscience better buy green electricity - you have done more for the environment.

Morning

As you already say, some system components do not complement each other here. However, the idea of supplementing the heat pump with a wood stove makes sense. Or a stove with solar thermal also works. First, think about how you want to heat, what effort you are willing to make. Is the desire for a stove serious and permanent? Possibly pellets?

Olli

Good morning and thank you very much for your answers. The most important key data I of course forgot: 3-4 person household. Underfloor heating throughout the entire house. Controlled residential ventilation with heat recovery. The fireplace (log wood) is included for coziness, whether water-bearing or not is still up for debate. Assuming the solar thermal system is removed, heat pump and stove remain: What type/size of water storage should I then take? I have read that for the heat pump a rather small storage tank (e.g. the offered 180l) is sensible. For the stove, however, a larger storage tank (600-1000l) would probably be more appropriate?

The small tank at the heat pump is for hot water (would be too small for me) and the large one by the stove is for heating water.

So you need both ;)

We have a 150l tank for the domestic hot water attached to the air-to-water heat pump. So far, I would say it is neither too big nor too small. We have forgone a wood stove with a water circuit and therefore a second tank. On the one hand, I wanted to save the effort, and on the other hand, I wanted an autonomous heating system that I can operate without electricity in an emergency.