ᐅ Hybrid heating system: Is combining a heat pump with a gas condensing boiler a practical solution for renovating older homes?
Created on: 19 Mar 2022 08:25
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taskyyy
Hello everyone,
In a detached house with an attached garage and 145 m² (1560 ft²) of living space, there is still an oil heating system installed, which now needs to be replaced.
Does it even make sense to install a heat pump combined with gas in an old building with poor insulation? Or would it be more practical to just install a gas boiler? Will the heat pump actually "kick in"? Or will the gas boiler always be the only active unit?
The advantage of the combination would be the higher subsidy. A subsidy for gas is only possible if solar thermal is installed, but that doesn’t seem very practical, right?
Does anyone have experience with this combination? What would you recommend? Or would it be better to first fully insulate and then simply install a heat pump?
The energy consultant I had, who is also certified by KFW, seemed totally unsure. Maybe someone here has a rough idea?
In a detached house with an attached garage and 145 m² (1560 ft²) of living space, there is still an oil heating system installed, which now needs to be replaced.
- The heating load is approximately 15 kW.
- The façade has a U-value of 0.97 W/m²K and double-glazed thermal insulation windows are installed.
- The roof is insulated.
- The top floor ceiling is insulated with 10 cm (4 inches) of mineral wool.
- Moreover, the house is fully basemented and the basement ceiling is insulated.
Does it even make sense to install a heat pump combined with gas in an old building with poor insulation? Or would it be more practical to just install a gas boiler? Will the heat pump actually "kick in"? Or will the gas boiler always be the only active unit?
The advantage of the combination would be the higher subsidy. A subsidy for gas is only possible if solar thermal is installed, but that doesn’t seem very practical, right?
Does anyone have experience with this combination? What would you recommend? Or would it be better to first fully insulate and then simply install a heat pump?
The energy consultant I had, who is also certified by KFW, seemed totally unsure. Maybe someone here has a rough idea?
D
Deliverer20 Mar 2022 19:21I am really a layperson here, but I guess the facade is not a problem.
I'm not an expert on facades either, but it sounds good (thick). Even Styrofoam insulation is already included. I would handle the windows and underfloor heating, add some extra insulation to the floor slab myself, and then calculate the heating load. The heat pump should work without many additional extras. Heat pumps receive good incentives, but for window replacement, you'll need to check if there are any available.
Just a heads up: Don’t let anyone sell you an oversized heat pump. It also needs to be modulating (able to operate below its maximum capacity).
Just a heads up: Don’t let anyone sell you an oversized heat pump. It also needs to be modulating (able to operate below its maximum capacity).
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