Cooling concept new building - split air conditioning / air-to-water heat pump cooling function / combination

Significant reasons for me were lack of time regarding personal effort (stressful job + small child + construction project is already enough), great distance between the construction site and current place of residence (approx. 300km), no experience of the heating installer with it, and if something goes wrong you have to dig up the garden again...

It depends entirely on the design: for example, with 18 degrees flow temperature, 23 degrees return temperature, and 20 l/min flow rate: (20*60)/1000 * 1.16 * (23-1) = 6.96 kW. However, this first requires determination of the required cooling load (usually significantly lower than the heating load). Are there already any results on this? This would be, by the way, generally the first step for me before selecting the technology.

No, there isn’t any yet. Thanks for the tip.

I would bring up the topic of BKA again with the contractor. Although to be honest I still have doubts whether it is worth it. I pay 5k EUR extra for the heat pump’s cooling function (5k) + BKA material (1k) + BKA installation (1.5k) + split unit in the office (7k) [except for the cooling function, all estimates of course]. Am I really coming out significantly under 19k in the end? I feel like I might save a bit but have significantly less cooling capacity?

My father-in-law suggested one idea, but I have my doubts about it and would be interested in your opinion. They live on the directly neighboring property and still have a very old oil heating system that will probably give up soon. His idea was whether boreholes for a groundwater heat pump could be made and the wells used jointly.

Advantages would be:
- Passive cooling
- Groundwater at approx. 6m depth, so not very complicated
- Shared costs for drilling

Disadvantages/risks:
- Is operating 2 heat pumps from one well even possible?
- Houses quite far apart (approx. 20m), is that even easily possible at that distance?
- Legal situation with cross-property installation?
- What if their house is sold / rented out?

Therefore, I am currently somewhat skeptical... but if BKA is potentially an option, such a groundwater heat pump would probably not be bad if it is reasonably cost-effective.

The well water must meet certain specifications so that the manufacturer can reliably guarantee the operation at all. Then it depends on the flow rate. In addition, the water may only be heated a few degrees and then returned. Whether you are even allowed to do this must be urgently clarified with the building authority and water protection. The simplest solution, also regarding performance and dehumidification, remains an air conditioning unit.

20 meters is no problem. Depending on the cable, it's just more expensive. We run 35 meters with our cooling line.

It might be an "extreme" counterexample to the solutions usually posted here, but we implemented it comparatively cheaply ;)

Our children's room and bedroom are directly adjacent to the garage side. In both rooms, we installed one indoor unit each, each connected to a separate outdoor unit. The two outdoor units are placed on the garage roof. Thanks to Comfee devices and quick connectors, the whole thing cost around €1,600 in total and runs perfectly :D It may not be "state-of-the-art," but it works great and even if these things give out after 5 years (which I don’t expect), I’ll just buy new ones.

In terms of performance, we cool the entire house with it. Doors open and you quickly notice how the cool air "falls down" into the living room over the open staircase. But we don’t need 19 degrees in the living room in the height of summer.

Certainly not comparable to professionally planned cooling concepts, but also at about a tenth of the price. It suits us for the two to max three months when you actually need air conditioning.

Whether you are even allowed to do this must be urgently clarified with the building authority and water protection.

In principle, we are allowed, that has been clarified. We are just not allowed to do it ourselves (specialist company) and it should be accompanied by an expert.

It’s really a matter of taste. Multisplit systems are simply more visually appealing because there is only one outdoor unit. But of course, they are not cheap. The Comfee systems for self-installation or those from any other manufacturer only differ in having multiple outdoor units, and not everyone likes that.

The point is that nowadays you have to think about cooling, and whether you do it with multisplit or singlesplit, or with ceiling cooling and chilled water units, or whatever else, is secondary.