ᐅ Alternatives to Outdoor Installation of an Air Source Heat Pump

If I had the choice, I would prefer a geothermal heat pump. It is even more efficient than an air-to-water heat pump and "probably" quieter as well.

However, you need to have a fairly deep borehole (or even two) drilled for this, which explains the significant price difference.

Unfortunately, I couldn’t install a geothermal heat pump because we are located in a water protection zone. Otherwise, as an alternative if the plot is large enough, you can install horizontal trench collectors.

Hello everyone,

Thank you for your replies.

@Wilder Süden: We were recommended the F750 model from Nibe. I will check the product sheet to see if I can find more information.

@Mycraft: Thanks for the explanation. I have heard before that an exhaust air heat pump might not be very efficient. What do you mean by a "pure indoor installation"? Does that mean a "standard" air-to-water heat pump that takes in and releases air through openings in the exterior wall? Can you recommend a product or manufacturer where I can read more about this?

@Myrna: We have already exchanged information with other builders in the development area. Ultimately, it seems to be a decision of the local authority. Additionally, one of our neighbors has expressed concerns about reducing the setback distances. We could possibly position it towards the other neighbor’s property, but then it would blow air onto our terrace. The problem is also that we have a relatively small plot of land.

@Deliverer: As mentioned above, if necessary, we would talk to the other neighbors again.

@Benutzer200: I am not familiar with the difference between a passive house and a KfW 55 standard house. I will try to find some information on that.

@Mahri23: We would need to explicitly check again if we can easily cover the additional costs.

Best regards
ConnyJash

All information without guarantee:

Air-to-Water Heat Pump for Indoor Installation: Protected from Wind and Weather
You can also install your air-to-water heat pump inside your home. An air heat pump designed for indoor installation is available in two versions. On one hand, there is the monoblock unit, and on the other hand, the split system heat pump. In the first case, a single device is installed inside the house, while in the latter, the air-to-water heat pump consists of two components. The indoor unit is smaller, and the outdoor unit is larger. In the split system, the noisier parts of the heat pump, such as the fan, are located outside.

Heat Pump Indoor Installation: The Air Duct
Setting up an air heat pump for indoor installation is quite complex. This is because wall penetrations are necessary to create air ducts that lead from the outside to the inside. These must be precisely fitted. This allows the heat pump to intake outside air to extract heat for space heating.

Thermal Short Circuit in Air Heat Pumps

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

If the air-to-water heat pump recycles cold exhaust air by drawing it back in, a thermal short circuit occurs. This causes cold and warm air to mix, reducing the heat pump’s efficiency. To prevent such a thermal short circuit, it is important that the air inlets and outlets maintain a sufficiently large distance from each other. Even a corner of the house or a wall in between can provide a simple solution.

ConnyJash schrieb:

Unfortunately, I don’t know the difference between a Passive House and a KFW 55 house. I’ll see if I can find some information on that.

A Passive House is understood as a building that, due to its high thermal insulation and the principle of significantly reducing heat loss through ventilation using a heat exchanger, typically does not require a conventional water-based heating system.
It therefore needs almost no heating at all; the occupants themselves produce nearly enough warmth. This level of efficiency is also what an air-to-air heat pump can manage.
In terms of capacity, it’s like trying to heat your entire house with just a hair dryer.

The additional costs for the necessary ground drilling would likely be a worthwhile and sensible investment in this case. Of course, you have to be able to cover these costs upfront, but considering this "special situation," it would be better to save money elsewhere if possible. Apart from that, there are certainly some cases where the extra costs are significantly lower than the mentioned 15,000 EUR compared to an air-to-water heat pump.

In our own planning with an air-to-water heat pump, all distance requirements were observed, including a 3 m (10 feet) gap to the neighbor. However, the neighbor installed theirs almost directly on the property boundary. That personally doesn’t bother me, so I didn’t raise the issue. But "workarounds" seem possible here, as long as neighbors reach an agreement and install devices that operate as quietly as possible.

Hello everyone,

We will soon be meeting again with our builder to discuss options and costs. In parallel, I spoke once more with our other neighbor. He is now considering whether we could possibly place the air source heat pump at his property boundary.

I will keep you updated!

Best regards,
ConnyJash