Air-to-water heat pump single-family house with basement - 150m² living area

So honestly now: Before I sign an offer or go into the final stages with a company and want to decide for it: Shouldn't I know exactly which model is being used here and what the heating load is in general for my single-family house?

In theory yes, in practice rarely possible. It might also depend on the type of construction. But at the time of awarding, you often do not yet have all the planning details. The question is also who then does the room-by-room heating load calculation. Of course, you can have that done. Ideally, however, you should already have an energy saving regulation calculation regarding the values of the building components, etc.

In theory yes, in practice rarely possible. It may also depend on the construction method. But at the time of awarding, you often don't yet have all the planning details. The question is also who does the room-by-room heating load calculation. You can of course have that done. Ideally, you should already have an energy saving ordinance calculation because of the values of the components, etc.

Yes, of course I understand the general contractor as well.. Before he incurs enormous additional effort that exceeds the costs (he still doesn't have a signature yet), no calculations will be made. But nevertheless, as the builder I think: Who tells me that the price won't increase after the offer is finalized? "Oh, we need a different air-to-water heat pump, the base price from back then is no longer sufficient, etc." I really can't protect myself at all in this regard, or maybe I then get an "standard" air-to-water heat pump that I don't even want?? The air-to-water heat pump I might want then costs 3k more, which he will of course then definitely charge me...

We were "just for fun" at a model home exhibition near us yesterday - we got a few inspirations for the furnishings, etc.

Since we are not even remotely "satisfied" with the heating and ventilation topic, we took another look behind the scenes there:

A company is currently installing a heating and ventilation combination from Stiebel Eltron - indoor installation (without an outdoor unit) - air-water heat pump + ventilation system in one device.

Is the device any good? Does anyone know about it?

That should be the model: Stiebel Eltron LWZ 5S PLUS.

How does the funding or the costs actually work?

Such an air-to-water heat pump usually costs maybe €10,000-15,000 - The costs stated in our offers for [BaFa]-funded devices are around €30,000. Are the installation costs etc. really that high?

Are the installation costs etc. really that high?

The model you mentioned is not just heating, but also controlled residential ventilation. The costs are usually in line with underfloor heating and ventilation ductwork. However, the installer still earns very well.

The model you mentioned is not only heating but also controlled residential ventilation. The costs usually include underfloor heating and ventilation piping. However, the installer still earns very well.

Yes, that’s true – it wasn’t necessarily related to the model.

As I said, we also have offers regarding air-to-water heat pumps Viessmann 200-S or 300A. These are roughly estimated at €30,000. Apparently, you then get the subsidy on the €30,000. But if, for example, the 200-S only costs €12,000, is the piping/installation really that expensive? I’m not getting a subsidy for the underfloor heating!