Alternatives to outdoor installation of an air source heat pump

If I had the choice, I would prefer a ground source heat pump. It is even more efficient than an air-to-water heat pump and "probably" also quieter. However, for that, you have to have a pretty deep hole in the ground (or even two) drilled. Hence the large price difference. Unfortunately, I could not install a ground source heat pump because we are located in a water protection area. Otherwise, as an alternative if the property is large enough, install trench collector loops.

Hello everyone,

thank you for your answers.

@Wilder Süden: We were recommended the F750 model from the company Nibe. I'll see if I can find more in the product sheet.

: Thanks for the explanation. I have heard before that an exhaust air heat pump does not seem to be very efficient. What do you mean by a "pure indoor installation"? Does that mean a "normal" air-water heat pump that sucks in and expels air through openings in the house wall? Can you recommend a product or manufacturer where I can read up on this?

@Myrna: We have already exchanged ideas with other builders from the development area here. Ultimately, it is probably always a decision of the municipality. In addition, one of our neighbors has already indicated that he does not approve of the reduction of the clearance distances. We could possibly place it on the other neighbor’s property, but then it would blow onto our terrace. The problem here is also that we have a comparatively small property.

@ : See above. In case of doubt, we would speak again with the other neighbors.

@ : Unfortunately, I do not know the difference between a passive house and a KFW 55 house. I’ll see if I can find something about it.

@ : We would explicitly have to check again whether we can easily afford the additional costs.

Best regards
ConnyJash

All information without guarantee:

Air-water heat pump with indoor installation: protected from wind and weather
You can also install your air-water heat pump inside your house. An air heat pump for indoor installation is available in two versions. On the one hand, there is the monoblock and on the other hand the split installation of the heat pump. In the first case, a single unit is located inside the house, and in the latter, the air-water heat pump consists of two components. The indoor unit is smaller, and the outdoor unit is larger. In the split installation, the noise-intensive components of the heat pump, such as the fan, are also outsourced outdoors.

Heat pump for indoor installation: the air duct
The installation of an air heat pump with indoor installation is quite complex. This is because wall penetrations are necessary for air ducts leading from outside to inside. These must be precisely fitted. This allows the heat pump to take in outside air to extract heat for space heating.

Thermal short circuit in the air heat pump

Visually, an air heat pump for indoor installation hardly differs from an outdoor unit | Illustration:
Viessmann Workshops

If it happens that the air-water heat pump sucks in the cold, blown-out air again, a thermal short circuit occurs. Cold and warm air mix – and the efficiency of the heat pump suffers. To prevent such a thermal short circuit, it is important that the air intakes and air outlets have a sufficiently large distance from each other. Even a corner of the house or wall in between can provide relief here.

I am unfortunately unaware of the difference between a passive house and a KFW 55 house. I will see if I can find something on that.

"A passive house is understood to be a building that, due to its high thermal insulation and the functional principle of significantly reducing ventilation heat losses by means of a heat exchanger, generally does not require a conventional water-based building heating system." It therefore needs almost no heating anymore; the occupants of the house alone are almost sufficient to produce enough warmth. And that is the level that an air-to-air heat pump can handle. In terms of performance, it is as if you want to heat your entire house with just a hairdryer.

The additional costs for the necessary ground drilling would probably be well and sensibly invested in this case. Of course, one must be able to afford these costs initially, but considering this "special situation," it would be better to save somewhere else if possible. Apart from that, there are indeed several examples where the additional costs compared to an air-to-water heat pump are significantly lower than the mentioned 15 thousand EUR.

In our own planning with the air-to-water heat pump, all distances were observed and 3 m to the neighbor was taken into account. However, the latter installed theirs almost directly on the property boundary with us. Personally, this doesn't bother me in this case, so I didn't even bring it up. But there seem to be "ways" here, provided neighbors reach an agreement and install devices that are as quiet as possible.

Hello everyone,

we will soon be meeting again with our construction contractor to discuss possibilities and costs. At the same time, I spoke again with our other neighbor. He is now considering whether we might place the air heat pump on his property boundary.

I will keep you updated!

Best regards
ConnyJash