Air-to-air heat pump vs air-to-water heat pump vs ring trench collector - differences

You should probably contribute your own work and enjoy it, and if you use a trench collector, you might get a brine-water heat pump without extra cost.

I see it that way now too. If you can contribute your own work (ideally even dig it yourself or know someone who can) and you read up on how everything must be installed, you can lay the trench collectors yourself and thus possibly even "make money" through the 35% subsidy, unlike an air-water heat pump which would not be funded (although there are also air-water heat pumps that now sometimes meet the criteria for funding). The best thing is to just have both planned with concrete examples. Especially if you cannot/will not do your own work for the installation or if trench collectors don’t fit the property at all (space, soil conditions…), it will probably be more expensive – here in the forum I found prices for drilling instead of trench collectors from 8-12K, so you can use a brine-water heat pump.

In general, you should also consider that you can get 35% funding from BAFA for many costs of an air-water/brine-water heat pump if the efficiency (annual performance factor >=4.5) is reached. This can also include the central ventilation unit (connected to the air-water/brine-water heat pump) as well as all other components (labor costs, control unit of the system) necessary to achieve the energy efficiency values.

Here it is best to find a skilled craftsman who knows about this and can calculate the different options.

How long have you been living there already and you really have a heat pump? I believe this heat pump is not running optimally.

In this case it's gas+solar. Standard heating in winter is 21°C; when you know you’ll shower the next morning, we just turn it up a bit to reach 22/23°C. As I wrote, this doesn’t really make sense if you keep turning it up and down. The temperature you want to have “constantly” in the bathroom should be calculated from the start.

Air-to-water heat pump: 100%
Air-to-air heat pump: 200-300%
Brine-to-water heat pump: 75%

And now calculate the manufacturing costs and the operating time against that.

Air-to-air heat pump up to around 10,000-15,000 euros?

Air-to-water heat pump with underfloor heating and controlled residential ventilation about 20,000-25,000

Brine-to-water heat pump with controlled residential ventilation and underfloor heating 25,000-30,000?

Is that roughly correct?

What can also be seen from this is that the smaller the total energy consumption, the less impact the chosen heat pump has. Thus, an air-to-air heat pump (if at all) only becomes interesting if the total energy consumption for heating heat is very low (passive house).

And therefore I find it all the more remarkable that the major prefab house manufacturers like Bien-Zenker, Weberhaus, Streif Haus, Schwörerhaus, etc., actively offer customers an air-to-air heat pump. And this, although none of them build a passive house as standard . In principle, the uninformed among the interested parties are obviously being taken for a ride here (low costs for the heating system = easier sales; the subsequent consumption costs are not an issue for the prefab house manufacturers).

Ultimately, the discussion here has further reinforced my decision to choose a brine heat pump...

Bien-Zenker, Weberhaus, Streif Haus, Schwörerhaus etc. actively offer customers an air-to-air heat pump

Well, whoever orders an air-to-air heat pump at Weberhaus and co also gets a primary energy demand that is almost passive house level.

And now calculate the manufacturing costs and the runtime against it.

Air-to-air heat pump up to 10,000-15,000 euros?

Air-to-water heat pump underfloor heating and controlled residential ventilation about 20,000-25,000

Brine-to-water heat pump with controlled residential ventilation and underfloor heating 25,000-30,000?

Is that about right?

I would have estimated it more like this (for KFW 55, 185 m² living space) - including ready-to-operate installation -:

1.) Air-to-air heat pump: 20 - 25 thousand euros
2.) Air-to-water heat pump including underfloor heating and controlled residential ventilation: 35 to 40 thousand euros
3.) Brine-to-water heat pump including underfloor heating and controlled residential ventilation as well as drilling: 45 to 50 thousand euros

And now calculate the manufacturing costs and the runtime.

Air-to-air heat pump up to around 10,000-15,000 euros?

Air-to-water heat pump with underfloor heating and controlled residential ventilation about 20,000-25,000

Brine-to-water heat pump with controlled residential ventilation and underfloor heating 25,000-30,000?

Is that about right?

Well, I can't say anything about air-to-air heat pumps.

I find air-to-water heat pumps with underfloor heating and controlled residential ventilation a bit too low. Although, of course, it depends on the region, square meters, and also the heat pump itself.
Controlled residential ventilation costs me 13,000 euros. Air-to-water heat pump with underfloor heating for 140 sqm + heated basement about 27,000 euros.

Brine-to-water heat pump including source? So horizontal collector or drilling? I also find the estimate decidedly too low with controlled residential ventilation.