ᐅ Which type of heating system is recommended for a KfW 55 energy-efficient house?

A Rotex HPSU Compact with an integrated 500L (132-gallon) hygiene buffer tank and an annual performance factor of about 3.9 is available for 6,900 euros including shipping. Commissioning costs 700 euros.

For 22,000 euros they should definitely be overcharging you.

Under normal circumstances, an air-to-water heat pump costs about the same or less than a gas plus solar system. But your general contractor apparently wants to make a good profit here, so it probably won’t be worthwhile for you.

Advantage of an air-to-water heat pump with the right model (like the Rotex): it can provide cooling.

Kaspatoo schrieb:
According to the consultant, air-to-water heat pumps and similar systems only achieve such a good annual performance factor because the electricity can theoretically be generated from renewable energy. He believes that in the coming years the government will reverse this. Industry associations are reportedly already calling for this or for modifications. I have not verified these statements.

This is complete nonsense. Either you have misquoted or the energy consultant has no idea.

To calculate the annual performance factor, you divide the heat produced in kWh by the electricity consumed for heat generation (also in kWh) over one year.

These are two figures that can both be determined at home, so how should the German or individual electricity mix have any influence on the annual performance factor?

Perhaps changes in the calculation of primary energy demand are meant, but these have nothing to do with actual consumption (and I doubt anyone can just change the calculation formula...). In my understanding, long-term political decisions about how our electricity is generated should influence this, e.g., which power plants will be needed in the future, and only then does the primary energy factor for electricity change. Depending on the development of the power plant fleet, the factor may improve or worsen compared to gas. Currently, the primary energy factor for electricity is 1.8 and thus worse than for gas (1.1). Before April 1, 2016, the factor was even 2.4.

This factor influences whether energy saving regulations can be met or not.

Hm, yes, I might have actually confused the factor for primary energy with the seasonal performance factor. Thanks for the clarification.

Severability clause: the rest remains as I stated/presented.

Kaspatoo schrieb:


Severability clause: the rest remains as I claimed/presented.

This suggests that you do not yet have an objective overview of the different heating technologies.

It would be very surprising if a house with an air-to-water heat pump could not be built at cost parity with a house using a gas condensing boiler.

Most recent posts in this forum indicate otherwise.

oleda222 schrieb:
Most recent posts in this forum suggest otherwise.

Really?
I have rather gotten the impression that contractors have their preferred solution and make deviations from it exorbitantly expensive. It’s a markup, basically. It costs more because the preferred solution was purchased in bulk or the deviation from the standard involves additional effort.

The fact that both system types are priced similarly by a heating installer is a completely different matter.

Yes, really. You have already explained the deviation yourself; the general contractor / home builder uses a standard that they only deviate from for an additional charge.

However, that doesn’t mean there aren’t suppliers who either sell air-to-water heat pumps as a standard nowadays (for example, Bauexperte, if I remember correctly) or who evaluate each house individually and choose the best heating system. In such cases, it definitely won’t be a gas condensing boiler plus something that ends up as an air-to-water heat pump.