New heating system for old farmhouse! Gas vs Gas + Heat Pump vs Heat Pump

Hello everyone!

I have a detached farmhouse. The pellet stove broke down last winter and was fed with sacks, which is very inconvenient. I want to move away from pellets since no pellet storage is planned. But first, the basic conditions:

Year of construction: around 1900, renovated from time to time
Ground floor: floor not insulated
1st floor: floor not insulated
Attic: not insulated -> The plan is to insulate the floor here
Roof: not developed
Basement: about 40 m², old vaulted cellar, not insulated
Walls: no external insulation, but mostly over 50 cm thick
Windows: wooden windows, double-glazed
Living area to be heated: about 180 m², radiators are available
Two wood stoves (kitchen and hallway) available. The wood stove in the hallway is also intended to be used for heating in winter.
Hot water currently only via instantaneous water heater

A liquid gas heating system with a tank is planned. The tank will be purchased and stored underground. The cost for the tank including the excavation and connection to the house is about 5,000 EUR. Operating costs include an inspection every 2 years for 40 EUR and an internal inspection of the tank every 10 years for 650 EUR.

1. I have an offer from the heating installer for the gas heating system with a 160-liter buffer tank for 14,000 EUR. A bathroom will also be supplied with hot water and pipes will be laid. We discussed the topic of heat pumps. He said that the existing radiators require a higher flow temperature and therefore would have to be completely replaced. Therefore, I have initially decided against the heat pump.

2. Then I had another heating installer who made a gas heating system combined with a heat pump attractive to me. There is apparently a gas heating system connected with a heat pump and, according to him, it selects the cheapest heating mode. If the heat pump runs inefficiently, the gas heating takes over. A written offer is not yet available. We did not discuss the replacement of the existing radiators.

3. Then I discussed the topic with a friend. He tells me that I should go completely for a heat pump (he also mentioned oversizing the heat pump in this context) and that I should not get the gas heating system at all. The weeks when the heat pump would be inefficient, I would simply have to heat with electricity. What do you think about that statement?

I look forward to your suggestions and experiences on the subject, I wish you a happy Father’s Day!

Without concrete numbers on heat losses, it is guesswork. I would be very cautious with statements like "fully relying on heat pump" and "oversizing".

Without concrete figures on heat losses, it's just guesswork. I would be very cautious with statements like "going full on heat pump" and "oversizing."

Thank you for your answer! What exactly do you need? Are there specific key figures here? How is the calculation carried out? For the farmhouse, I initially assume high heat losses. Should I consult an energy advisor here?

You should have the heat loss of the house calculated. As a reference, it would also be interesting to know how large (kW) the former pellet system was and whether the house could be heated well with it.

You should have the heat loss of the house calculated. As a reference, it would also be interesting to know how large (kW) the former pellet system was and whether the house could be heated well with it.

I am more interested in a tendency than in a calculated value with my question. The pellet heating was probably undersized, and the house was never really warm. I believe the pellet stove had a power output of 15 kW. The first offer included a gas heating system with a power output of 25 kW.

So if a 15kW oven was apparently too little, then I wouldn't waste any more thought on a heat pump. If it is not supposed to become a money pit, one could consider it if the house can be heated with less than 10kW.