Old gas heater defective -> need a new one, but which one?!?

Good morning,

we have bought a small house that was built in 1936 and renovated in 2013.
Last year we looked at it and bought it. Considering that the heating system was from 1997, we thought we would have to renew it "soon".

House: approx. 145m² living space, roof insulated, thick exterior walls. Windows with double glazing, fireplace in the living room.

The chimney sweep wanted to shut it down 2 weeks ago because there was a strong gas smell in the basement, and since we open the windows downstairs & have 2 small children, he refrained from doing so. On advice, we should order a new heating system, as repairing it would be a waste of money.

Now we had 4 different heating companies here.. The topic came up (because I wanted alternatives as well):

[*]Gas condensing boiler -> Gas connection would be available, it would be cheaper but is not subsidized (CO2 tax, dependent on gas price)
[*]Pellet heating -> different opinions -> Would not work in the basement due to too high humidity (another heating expert says it’s nonsense) -> higher acquisition costs -> price of pellets similar to gas price, subsidized up to 35%
[*]Wood log stove -> high acquisition cost, must always be refilled by hand -> subsidies, no information given
[*]Air-water heat pump -> is subsidized, the heating specialist received measurements of every single room with ceiling height, on which he then calculated the heating demand for the whole house and designed the air-water heat pump accordingly. According to him, he has had good experiences with it -> but electricity prices will become more expensive... would also need a higher annual performance factor to be worthwhile??

Since we have a 27kW instantaneous water heater in the basement for our hot water, the question is also whether it should be removed and the water heated with the new heating system.

We had planned to install a 10 kWp photovoltaic system on the roof anyway.

I know it’s everyone’s own thing. But I wanted to become a bit more independent from fossil fuels.

Hope you can help me a little?!

Best regards

Well, just add to your variants what it should absolutely cost.
I'll guess:

Gas condensing boiler somewhere between 4-7K€
Pellets >20K€
Wood log stove, welcome to the Middle Ages, >15K€
Air-to-water heat pump is probably crazy with this year of construction due to the much too high heating heat demand for this year of construction. Minimum new radiators on top >15K€

Switching the hot water supply away from DL is not a bad idea, but it's equivalent to a renovation. You should have done that before moving in. A 20-year-old gas boiler is also already close to the end, not to mention consumption costs. You really missed the sensible time last year.

For me, it's clear that gas condensing boiler is the sensible solution. Subsidies won't help either.

We bought the house in December and could only move in mid-January.

So new radiators are already present in the house and there is underfloor heating in the bathroom.
So far I have one offer:

[*]Gas condensing boiler Therma Modula 25kW -> complete with installation €10,700 (Energy efficiency: A)
[*]Pellet heating 6-16kW with 4t storage -> complete with installation €23,685 (But there is a subsidy of up to 35%) (Energy efficiency: A+)

So new radiators are already installed in the house, and there is underfloor heating in the bathroom.

If the heat pump is to become at least somewhat efficient, then you need both to be designed for low temperature. That will not be the case here. So once again new.

Get another comparative offer for gas.

We bought the house in December, and we were only able to move in mid-January.

Renovation measures are done BEFORE moving in.

Take the gas BWT, if necessary recalculate whether the 25kW is really needed and also check with other providers. It can then be installed in one day and you will have about 20 years of peace again.

If the heat pump is to be reasonably efficient, then you need both designed for low temperature. That will not be the case here. So once again new.

Get a comparative offer for gas.

Renovation measures are carried out BEFORE moving in.

Everything was renovated in 2013 except for the heating. And we were assured that the heating would last a few more years.. accordingly it was not so, and according to the lawyer we can do nothing..

I will get a few more offers..

Take the gas BWT, possibly recalculate whether the 25kW is really necessary and yes also look at other providers. It can then be installed in one day and you will have peace for about 20 years again.

Ok, then I will get a few more offers from the area.