Final energy demand achievable without insulation

Hello everyone,

the calculated energy demand of one of the houses we are interested in is as follows:



The house is built with Thermoplan S9 bricks with a thickness of 36.5 cm, the roof is fully insulated with 30 cm of stone wool, and the windows are triple-glazed. Otherwise, I am not aware of any further insulation measures. Heating is done with an air-to-water heat pump.

The final energy demand of 17.9 kWh/(m²*a) seems very low to me, since no additional insulation was carried out, or is this achievable with the mentioned materials?

We originally wanted to use an insulated brick, with which we would have an final energy demand of 16 kWh/(sqm*a) and a primary energy demand of 26 kWh/(sqm*a). Now we have chosen ytong and according to the energy certificate a final energy demand of 16 kWh/(sqm*a) and a primary energy demand of 28 kWh/(sqm*a). All without additional insulation. So it is definitely possible and much nicer than styrofoam on the facade.

: Thanks for the answer. The Thermoplan S9 roughly corresponds in insulation performance to a Ytong of the same thickness. I assume you also have correspondingly low heating costs?

I’m just a bit surprised because this construction method is much more appealing to me (and many others), but you rarely find it. So I wonder why it’s not built more often. Are the construction costs higher here than with insulation?

we also built with internally insulated stones 42cm, all good. It is more expensive than insulation in front of a thin 15cm wall

I cannot say the heating costs yet, we are only moving in in 1 week. But we estimate 60-70€ per month for heating costs. Yes, the construction method is more expensive, especially with the insulated bricks, everything must always be covered during construction so that the insulation does not get wet. That is why we also decided on the 36.5 ytong and even achieved KFW 55 with it.

I can't say the heating costs yet, we are only moving in in 1 week. But we expect 60-70€ per month for heating costs. Yes, the construction method is more expensive, especially with the insulated bricks, everything must always be covered during construction so that the insulation does not get wet. That is why we decided on the 36.5cm Ytong and even achieved KfW 55 with it.

Most people still build with unfilled bricks. Ytong is soundproofing worst case.