ᐅ Old gas heating system broken – need a new one, but what kind?

Good morning,

we bought a house that was built in 1936 and renovated in 2013.
Last year we viewed it and decided to buy it. Considering that the heating system dates back to 1997, we thought we would need to replace it “soon.”

House: approximately 145m² (1,560 sq ft) of living space, insulated roof, thick exterior walls. Double-glazed windows, chimney in the living room.

The chimney sweep wanted to shut it down two weeks ago because there was a strong smell of gas in the basement. Since we keep the windows open downstairs and have two small children, he decided against it. On his recommendation, we should get a new heating system because repairing the current one would be a waste of money.

We have now had four different heating companies inspect the house. The discussion came up (because I wanted to explore alternatives):

• Gas condensing boiler – a gas connection is available, it would be cheaper but is not subsidized (due to CO2 taxes, depending on gas prices).
• Pellet heating – mixed opinions – one expert said it wouldn’t work in the basement due to high humidity (another specialist said that’s nonsense) – higher initial costs – pellet prices are similar to gas prices and it is subsidized up to 35%.
• Log wood stove – high initial cost, needs to be refueled by hand regularly – no clear information on subsidies.
• Air-to-water heat pump – subsidized, the heating specialist took measurements of every single room including ceiling height to calculate the heat demand for the whole house and size the heat pump accordingly. He said he has good experience with it – but electricity prices will rise… it would also need a higher seasonal performance factor to be worthwhile.

Since we currently have a 27kW (36 hp) instantaneous water heater in the basement for hot water, the question is whether that should be removed and the new heating system used to heat the water as well.

We are planning to install a 10 kWp photovoltaic system on the roof anyway.

I know this is a personal decision, but I would like to become a bit more independent from fossil fuels.

I hope you can help me a little!

Best regards