Fresh air heating vs. air-to-water heat pump indoor installation, alternatives??

Hello everyone,

we are currently planning a new house. Unfortunately, according to the development plan, the municipality prohibits the outdoor installation of air-to-water heat pumps. I personally find indoor installation annoying at the moment (space in the utility room, huge holes in the wall, noise(?)), but I’m happy to be convinced otherwise. We have now received initial offers with a fresh air heating system (air-to-air heat pump), which I personally find very appealing because of the filtering and cooling function and thus the possibility of sleeping with the window closed in summer (highway in sight without a speed limit, <<1km). Unfortunately, I haven’t found anything good online about such a fresh air heating system (and little well-founded negative feedback...). At least not if the outdoor installation of an air-to-water heat pump and thus underfloor heating is not an option. Also, no provider has so far responded in detail to my inquiry regarding the horizontal ground collector (due to cost). Fossil energies are fundamentally excluded, electricity will come from the roof (possibly with storage).

1) Has anyone of you had good experiences with a fresh air heating system (diffusers in the ceiling)? --> Bathroom planned with infrared elements in the ceiling
2) What would be a reasonable alternative?
3) Is an integrated installation of the air-to-water heat pump really as bad as the house builders make us believe? --> Unfortunately, they only tell you what’s advantageous for them, and in prefabricated houses that is “ventilation is the best thing since the invention of beer” ;-)

Oh, KFW-55 standard, optionally KFW-40, no basement, approx. 150m² living space with a pitched roof. Funding is initially secondary.

Thanks

Flitzer

1) Has anyone of you had good experiences with a fresh air heating system (diffusers in the ceiling)? --> Bathroom planned with infrared elements in the ceiling

Only at work - KFW 55 is a no-go for that. Advantage: dirt cheap compared to conventional heating. Most of the costs then come during operation...

2) What would be a sensible alternative?

Brine-water heat pump. Trench collector is the classic perfect DIY area. Or the shell constructor just digs the trenches in the garden for a box of beer. No additional costs arise. Also not for the builder.

3) Is an integrated installation of the air-water heat pump really as unattractive as the homebuilders make us believe?

Total nonsense. That is a common (though not so frequent) variant.

They unfortunately only tell you what benefits them, and that would be in the prefab house sector "ventilation is the best thing since the invention of beer" ;-)

Sure, air-to-air heat pump is of course at an advantage. For the builder. He saves himself the expensive heating with underfloor heating and installs a blower for you. But he charges well for that... The indoor heat pump can go anywhere. Even into the attic, if available. Of course it causes noticeable noise. But that can be easily managed with construction measures.

Hello user 200 :cool:

Thanks for your detailed answer.
Why is ventilation a no-go for a KFW55 house? Insulation not sufficient? Or when would it work?
What realistically speaks against an air-to-air heat pump with heat recovery besides power consumption? Can't they achieve the temperature level, have hygienic problems, consume too much electricity, or are they all useless? I'm just trying to understand why everyone is against it except those who sell it. If I already have a solar system on the roof, the heating can well use electricity, it's off at night anyway, and in winter the air-to-water heat pump also uses a lot of power.

I also naively imagined the ring trench collector like that (just quickly dig a hole next to it, throw in the pipe, done)... but somehow everyone resists at first in the conversations, I need to follow up on that... Own work within the trades is unfortunately difficult because of warranties and not even that cheap if you have to rent the excavator. --> unless the excavator driver spontaneously does it with the foundation plate --> the construction management and the developer will know then, and both will keep their hand (in) on it.

The heat pump in the attic would be an option I only considered briefly... there's still that clattering thing in the house, above the bedrooms...

Regards Flitzer

Ultimately, this is a direct electric heating in the ventilation. So 1 kWh of electricity = 1 kWh of heat. A very expensive way to heat because roughly you have a heat demand of 5000 kWh, so heating costs of 2000-2500€. For a new building, this is definitely not appropriate

Just fire up the big search engine. And don’t click on a result where a manufacturer of such devices is behind it. It would be helpful if you acquire some basic knowledge about it if you want to understand.
In principle, you have to imagine that an air-to-air heat pump is not a classic heat pump. That means it does not convert energy from an external circuit, air, water, or brine into heating energy. Instead, it uses the energy from the exhaust air of the house and tries to return as much of it as possible back to the fresh (cold) air from outside in order to warm it up. But you can only return what is there. There are losses involved. Otherwise, you would have a perpetual motion machine. These losses have to be compensated again. For this, the supplied air is preheated and/or reheated. This happens with electricity. Unlike heat pumps, not in the ratio of 1:3 - 1:5 but 1:1 (I’m not an expert on this, but it only serves to illustrate).
The principle works in a passive house. Because it is so well insulated that there are hardly any losses. These are balanced by solar and internal gains, and if heating is needed occasionally, it doesn’t matter much. Because on the other hand, you save some technology like underfloor heating, for example. In an average KfW55 house, you have too many losses. You won’t be happy with it, especially not with rising electricity prices.
And forget about photovoltaics. That is a nice additional/side effect that also makes sense. But when you need the most energy, you have little or no yield, i.e., in winter. And no, the heating is not off at night. Night setback usually doesn’t make sense in a modern house.

We have an air-to-water heat pump installed indoors. 1x supply air 1x exhaust air with covers in the exterior wall. So no big ugly holes. I find it nicer than the units somewhere in the garden.

Noise Warm water preparation and defrosting are a bit louder. In everyday life it goes unnoticed, when it is quiet you can hear it clearly. Normal heating operation is really very quiet.

With a fresh air heating system near the highway, I would rather have concerns, besides the high heating costs, that you bring the noise through the openings into every room.