Underfloor heating in an old house, installation above the floor slab. Efficiency and costs?

Hello,

as has already correctly written, you should under no circumstances carry out the renovation on your own! Even if you are an expert in a specific field, there are many things to consider that you have probably never heard of.

Now the whole thing is to be replaced by a gas condensing boiler (tank to be placed in the garden) and underfloor heating.

Are there already exact calculations as to whether underfloor heating would even be worthwhile, and if so, how closely the installation would have to be done?

You write further down that you have budgeted EUR 60,000 for the renovation; in my opinion, that will not be enough. Especially with an old building, there are always new surprises; I know this very well, as we are currently renovating two houses.

Have you looked at the KfW subsidies? If not, you should do so promptly, in any case _before_ you fall into actionism.

One way or another, you should hire a professional as support. Among other things, he will also tell you a lot about the windows, which you want to have installed by a mason. If some of them are floor-to-ceiling, the roofer will certainly have a say as well.

The bonus on top – if you apply for subsidies for the renovation and commission an energy expert, the costs for the expert will also be subsidized.

Rhenish greetings

Removing the screed and properly insulating plus using dry screed is a good idea, we did the same with our house, which is also a house on a strip foundation on a slope. Whether or not underfloor heating (we have it!) is used, insulating the floor makes sense and is not really expensive. We had a quote for chipping out the screed in the lower level area (split level) of about 60 sqm for 2000 euros, but we preferred to do it ourselves. With two people it can be done in 1-2 days (chisel, sledgehammer). When insulating, you should meet the U-value required by the Energieeinsparverordnung, because you never want to have to redo it later. For us it was 2 cm 035 plus 6 cm 022 plus 25 mm 035 from the underfloor heating system panel (dry system). That results in a total buildup of about 13 cm. It’s best to get an energy consultant from the DENA list (google).