Cabinet with air-water heat pump, water storage.. Does anyone know it?

The only alternative I know of is wall heating (with clay I would find it perfect), but it is considerably more expensive than underfloor heating

You should have a room-specific heating load calculation done anyway, and then have the heating surfaces planned accordingly. Maybe your energy consultant can do that. You can then have wall heating installed additionally to the underfloor heating in certain spots where it is necessary due to the floor or other factors. I would only forgo underfloor heating if it is harmful to the floor; otherwise, it always provides some heating capacity.

With us, the normal air exchange rate is enough to heat the house. If there is a higher heating demand, it only works with warmer air and/or a higher air exchange rate.
The following questions arise
- How comfortable is it then to sit or stand next to a hot air blower?
I could set the system to the highest level (it never was before except at night in summer) Temperature will be difficult, I activated the summer bypass yesterday
- Higher electricity costs because controlled residential ventilation with heat recovery runs at full load more often
- Higher electricity costs because the compressor runs more
- Does the emergency/auxiliary heating turn on faster?
I could imagine yes

How effective it is with underfloor heating and thick wooden floors I have no idea

It is not a pure exhaust air heat pump


The service is coming next week, but I won’t be there to drill.
In any case, it is interesting what happens if, for example, the boiler for hot water is defective? Does everything have to be replaced (as rightly pointed out here) or are there spare parts?

difficult I installed the summer bypass yesterday

Just out of interest, can the bypass switch automatically? With us, the heat recovery does not run at night, but when it is warmer outside, the supply air is cooled down by the heat recovery. It doesn’t really make much difference or harm, of course, we have found that air transports little heat

It is not a pure exhaust air heat pump

Yes, but in connection with controlled residential ventilation with heat recovery, you also have no advantages from the exhaust air being used by the heat pump, i.e. it is unnecessarily complex.

Boiler for hot water is defective? Everything must be replaced (

The answer will be that, of course, there are spare parts. But think 10-20 years ahead. Then it will be replaced, and everything at that, because repair is not worth it. Can you then install "simple" devices from any manufacturer or again something for 20k?

What do you mean by that? I take out the heat exchanger and insert the summer cassette (styrofoam chunks). After that, I have to tell the system that the summer cassette is inserted. It should be like that for all combined devices of the brand, e.g. LWZ 504. Active cooling, so that the supply air is cooled, is not possible – whether this will come later or if the series devices already can do it, I don't know. I didn't miss it last year. If the outside temperature is 2 hours above the desired indoor temperature, it locks out; if the outside temperature falls below the current indoor temperature, it switches on. Last year we usually had 23 degrees in the house. Active cooling is not necessary, but it would certainly be comfortable. Heat recovery is about 90%, the rest runs via the pump. That sounds logical to me and not unnecessarily complex. The rest of the heat has to come from somewhere. Pure reheating with electricity at double-digit negative temperatures makes the electricity provider happy. How is it with separate controlled residential ventilation and air-water heat pump? Yes, in 20 years the patents will have expired, [Passivhaus Standard], and then there will be free choice. If one wants to, maybe one stays loyal to the brand because, for example, the service fits.

I take out the heat exchanger and put in the summer cassette (styrofoam chunks).

Understood, thanks for the info. We "cool" passively through heat recovery, which then uses the cooler indoor air to slightly cool down the warmer supply air just above indoor temperature. If it's colder outside, then the heat exchanger is inactive. But that's pure theory without much effect. Our controlled residential ventilation has rotation, so it's also a special type with pros and cons. If I’m seeing it correctly, the heat pump uses the exhaust air in addition to or exclusively the outside air, like a normal air heat pump. Your heating has 3.x kW purely through the heat pump. For our house (150m2, between KFW 55 and 40 with controlled residential ventilation) that’s enough so that the heating element does not have to be switched on. On paper it wouldn’t be enough, but in reality it is. How much the efficiency drops compared to water and how warm the air would have to be here I can’t judge. I’m curious about your consumption. There are other candidates where just the company name is enough to know it’s rubbish.