Water-bearing fireplace with oil heating (single-family house, old building)? Costs?

Hello, in the meantime we have viewed a dreamlike, well-maintained old building that we might consider as a new home.

Major drawback: High energy costs are to be expected.

Key data:
Built in 1930
200 sqm living space, 2 floors plus converted attic
Oil central heating 20 years old, 21 KW, operated in low-temperature range
(with 2 people, but we would be 5!).
Gas connection available!
Final energy demand is 289 kwh/(m²*a)! Energy efficiency class H!!!

That means I am pessimistically calculating up to €3,000 heating costs per year with 5 people, oil price increase, cold winter, etc.!

My idea (and before we buy or renovate anything, we will of course get professional advice, this is more about gathering ideas and rough cost assessments) would be to install a water-bearing stove (Grundofen?) in the living room and connect it to the central heating (with heat storage, control, domestic hot water heating (except in summer?), later possibility of solar integration, etc.).

2 chimneys are available.

Since my parents own forest and equipment to harvest wood, we would get the wood "almost" for free (of course, this includes labor, transport costs, equipment operating costs, etc.).

What would the conversion by a specialist company approximately cost?
What would the (additional) operating costs with maintenance, etc., be?
What energy/cost savings could be expected and when would the investment pay off?
Would a KfW loan be available here?
What would change in the calculation if the solar heating for domestic hot water (in summer) were installed right away?
According to the new energy saving law, would the whole house also have to be renovated (insulation, etc.)?
What would the alternatives be?

Hello Passivhaus,

I had the same idea because I also get wood under the same conditions, but for us, the path to the heating system would have become enormously complicated, i.e., the cost or the savings depend on how far the fireplace is from the heating system and how much renovation work is necessary.

The contact person is therefore a heating engineer, although I suspect that it will be similar for you as it was for me, namely that it is a nice-to-have but realistically does not pay off.

So, in principle, we only refreshed the old system with new pumps and radiators, kept everything else as it was, and can quickly generate local heat for the living and dining rooms with the stove if needed. The house (built 1918/1978) was additionally insulated during renovation/refurbishment in 2011, finished. Consumption has also dropped drastically since then; the four of us use about the same as the previous owners with one or two people, although our property was partially not insulated at all when we took it over, i.e., you could throw a screwdriver from the attic through the roller shutter box down to the basement (sic!).

Therefore, I would only install a fireplace with water heating in new buildings or if you actually tear out/renew all the water pipes including underfloor heating and the heating system itself in your house.

Best regards
Dirk Grafe

Hello,

how would it look if I were to place a stove in the living/dining room and create a connection to the three children's rooms above (1st and attic floor) by means of core drilling. My parents had something like that a long time ago in the house, before they had central heating. That way, I could heat the most important living spaces with wood.

Acoustically a disaster. Your children can't sleep when you have guests. I wouldn't recommend it - better to install a wood central heating system in the basement instead of the oil heating and insulate the house from the outside.

Why not have a heating boiler that can be switched optionally, which uses gas and wood? If someone is there, wood is used for heating, and if no one is there to add more, the heating switches to gas?

asks Sylvia

Hello,

what would be the benefit of replacing the 20-year-old oil heating system?
And if yes, with what?