Omit the single room rule? Controlled residential ventilation + gas heating, new construction

The next economic nonsense is the obligation to install a solar system on the roof for hot water for 6000€, as a penalty for gas boilers, it does not pay off in 30 years, but there will be no exemption for that

Instead of solar, maybe your controlled residential ventilation system might suffice. For that, you need an energy saving ordinance certifier who can manage that. If you build "energy efficient" (KFW), the exemption for the ERR is indirectly even more necessary than for the energy saving ordinance – as far as I know – since the HB of the KfW must certify the correct installation of the heating system.

Instead of solar, your controlled residential ventilation might also suffice. For that, you need an energy saving ordinance verifier who can manage that.

If you build "energy efficient" (KfW), the exemption for the ERR is indirectly even more necessary than for the energy saving ordinance – as far as I know – because the HB of the KfW must certify the correct installation of the heating system.

Our architect is trying to make it work, but it is probably very difficult to achieve with controlled residential ventilation alone.

We are building without KfW, so it's fine.

Our architect is trying to manage it, but it seems very difficult to achieve only with controlled residential ventilation.

My architect informed me that he does not understand many of his calculations (those of the software) or does not bother to try. There are general contractors who offer the combo gas + controlled residential ventilation as standard for normal energy-saving regulation pitched roof houses. It is possible.

For a possible retrofitting via radio, for individual rooms, would it be enough if a few 3x1.5mm cables lie in the heating circuit distributor? Then, retrofitting a control system with battery-operated room thermostats and radio valves should be easy, right? Just in case.

Yes, but in case of emergency cables would of course be better.

We had cables prepared for most rooms (HB/electrician unfortunately persuaded me otherwise), in hindsight I should have been consistent there.

My architect told me that he does not understand many of his calculations (those of the software) or does not bother to try. There are GCs who offer the Gas+Controlled residential ventilation combo as standard for normal energy-saving ordinance pitched roof houses. It is possible.


Yes, but in case of doubt, cables would of course be better.

We had cables prepared for most rooms (HB/Electrician unfortunately talked me out of it), in hindsight I should have been consistent there.

Thanks, we are building a flat-roof house, don't know if that makes a difference.

But the purchase price is also 5000€ higher and unknown electricity price, gas is still so established in Germany also in many public institutions, they don't quickly turn the price screw extremely, at least that's my opinion.

Well, it depends on the offer. An air-to-water heat pump without photovoltaics should cost less than gas+solar. An air-to-water heat pump with photovoltaics is clearly much more expensive, but after 20 years you have regained the investment; with gas and solar, nothing pays off. For example, I paid about 20k€ for the entire heating and photovoltaic system and practically 0€ heating costs. (just as an extreme example)

If you build "energy efficient" (KfW), the exemption for the ERR is indirectly even more necessary than for the Energy Saving Ordinance

Yes, with a KfW loan I would also avoid that, because you quickly get into the topic of "fraud".

Thanks, we are building a flat-roof house, don't know if that makes a difference.

Flat roofs and photovoltaics work perfectly (as long as there is no shading). Make the edge around the roof a bit higher, mount a 10kWp east-west system on it, and you have electricity without changing the architecture. Priority on self-consumption (battery), feed in overproduction. If the liquidity is there, it's a "no-brainer".