ᐅ New Heating System for an Old Farmhouse! Gas vs. Gas with Heat Pump vs. Heat Pump Only

Hello everyone!

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

Year built: 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 converted/living space
Basement: about 40 m² (430 sq ft), old vaulted cellar, not insulated
Walls: no external insulation, but mostly over 50 cm (20 inches) thick
Windows: wooden windows, double-glazed
Heated living area: about 180 m² (1,940 sq ft), radiators are installed
Two wood-burning stoves (kitchen and hallway) available. The stove in the hallway is also intended for heating in winter.
Hot water currently only through an instant water heater

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

1. I received an offer from a heating contractor for a gas heating system with a 160-liter (42 gallons) buffer tank for 14,000 EUR. This will also supply one bathroom with hot water and includes pipe installation. We discussed heat pumps. He said the existing radiators require a higher flow temperature and therefore would need to be completely replaced. That’s why I initially stepped back from the heat pump option.

2. Then another heating professional came by and recommended a combination of gas heating and heat pump. Apparently, there is a gas heating system connected to the heat pump that automatically selects the most cost-effective heating mode. If the heat pump runs inefficiently, the gas heater takes over. A written offer has not yet been received. We did not discuss replacing the existing radiators.

3. I also discussed it with a friend. He told me to fully invest in a heat pump (he also mentioned the risk of oversizing the heat pump) and to not buy the gas system at all. The weeks when the heat pump is inefficient, I would just heat with electricity. What do you think about this approach?

I look forward to your suggestions and experiences on this topic. Wishing you all a nice Father’s Day!

Without concrete numbers on heat loss, it is just guesswork. I would be very cautious with statements like "fully rely on a heat pump" and "oversizing."

Mycraft schrieb:

Without specific figures on heat loss, it’s just guesswork. I would be cautious with statements like “fully relying on a heat pump” and “oversizing.”

Thank you for your reply! What exactly do you need? Are there particular key figures? How is the calculation done? For the farmhouse, I’m initially assuming 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 useful to know the size (kW) of the previous pellet heating system and whether it was sufficient to heat the house effectively.

Mycraft schrieb:

You should have the heat loss of the house calculated. As a reference, it would also be useful to know the size (kW) of the previous pellet heating system and whether it was sufficient to heat the house well.

My question is more about getting a general idea rather than an exact calculation. The pellet heating system was probably undersized, and the house was never properly warm. I believe the pellet stove had a capacity of 15 kW. The first quote included a gas heating system with a capacity of 25 kW.

So if a 15kW (15,000 watts) heater apparently wasn’t enough, then I wouldn’t even consider a heat pump. If you want to avoid a money pit, it might be worth considering only if the house can be heated with less than 10kW (10,000 watts).