ᐅ Passive house / KfW40 / KfW55 with gas condensing boiler possible?

Is it possible to achieve one of these standards using a gas condensing boiler combined with a solar thermal system and

- sand-lime brick masonry with heavy insulation
- controlled residential ventilation with heat recovery
- nearly optimal south-facing orientation (south-southwest)
- triple-glazed windows
- underfloor heating with very low supply temperature
- a square floor plan without bay windows, projections, etc. / "town villa" style with 2 full floors

Is this also economically feasible?

(I mean, with a gas condensing boiler you have the lowest initial investment costs but the highest cost per kWh – so savings should be most effective there, right?)

I haven’t given much thought to the floor slab so far; I assume there are standard thicknesses and insulation used here?

As always: calculations need to be done. It’s not only about the orientation but also the type and number of windows. From my experience: KfW 70 is achievable; anything less than that requires substantial additional effort (if gas heating is installed). ==> not economical over a finite evaluation period

Hello,

Grym schrieb:
Is it possible to achieve one of these standards with a gas condensing boiler and solar thermal system and

- calcium silicate masonry with heavy insulation

What exactly do you mean by “heavy insulation”?

Grym schrieb:

- controlled residential ventilation with heat recovery
- nearly optimal southern orientation (south-southwest)
- triple-glazed windows
- underfloor heating with very low supply temperature
- square floor plan without bay windows, projections, etc. / “town villa” with two full stories

Is reaching one of these standards feasible? Is it also economical?

This is a question that depends on many factors and unfortunately cannot be answered through this forum. Based on experience from many building projects, I would guess that with this package you will “probably” reach an energy standard similar to KfW 70, but certainly not lower. Achieving more requires additional measures.

Regards, Bauexperte