ᐅ Is it worth preparing for air conditioning installation?

Tolentino schrieb:

That wasn’t the point of the last question. It was about whether installing an air conditioning system alongside the heat pump could negatively affect meeting a KfW standard.

Unfortunately, yes. In the past, energy consultants may have overlooked this, but nowadays it’s no longer allowed. Up to two devices can be covered by a photovoltaic system, but with a third device, you lose all funding. Since we are currently in the planning phase ourselves, these are reliable statements—at least for a 55 standard house. We will probably just install the wiring first and wait through the first summers. If it really becomes unbearable, we will consider installing it anyway.

Bauenaberwie schrieb:

Up to two devices can be covered by a photovoltaic system; from the third device onward, there is no subsidy at all.

Since often only one device is sufficient in modern single-family house designs, this clause is rather pointless.

Mycraft schrieb:

Since one system is often sufficient in modern single-family home constructions, this clause seems rather pointless.

But even one system must be limited by a photovoltaic system. And the energy calculation must be redone.

HoisleBauer22 schrieb:

Do you have any evidence for that?

No. I would just find it surprising if there were a connection. Whether I cool with a built-in heat pump for heating or – more efficiently – with a split air conditioning system, it doesn’t change the theoretical energy demand of the building. The actual demand might change (in either direction), but that is not decisive for the KfW.

Regarding the BAFA subsidy: Last year, private systems were also eligible. However, the condition "mainly for space heating" was already included then. Since a lot has changed with subsidies, it’s possible that this support no longer exists. It may also be that new buildings were excluded. This doesn’t change the fact that air conditioning systems are initially recognized as efficient heating systems.

By the way, I wouldn’t agree with this part:

HoisleBauer22 schrieb:

And since air conditioning systems require a lot of electricity,

Of course, this is a matter of opinion – but relative to heating, it is not a large amount of energy. I have roughly a ratio of 10:1, heating energy to cooling energy, in both a new and an old building. In figures, that’s 500 kWh for a 140 sqm (1507 sq ft) old building and 200 kWh for a similarly sized KfW70 new building (at about 22–23°C (72–73°F) indoor temperature).

We have air conditioning and wouldn’t want to be without it again.
I would definitely recommend at least preparing for it. Summers are likely to get even hotter over the next 20 years.

In our case, fairly large pipes run through the walls for the condensate water that needs to drain. I’m glad we have that concealed within the walls.
We have three split units for 150m² (1,615 sq ft). One in the living/dining/kitchen area (open plan), one in the office, and one serving the entire upper floor (bedrooms).
The unit on the upper floor runs during the day in summer when the sun is shining (because we generate energy with photovoltaics then), and we leave the doors open to the bedrooms we want to cool. This works well for us, also because the air circulates throughout the house due to the ventilation system’s airflow.
With this approach, I can only recommend not placing the split unit too close to staircases as we did. Even though the cooling works well, cold air tends to sink downwards, and when there’s a staircase... well, our hallway in the basement is always pleasantly cool in the summer. 😀

Pitigliano schrieb:

Are there any experiences from the community on this, or are these just empty "threats" from the KfW?

It’s similar to dealing with the tax office or a toothache... it might happen, but it also might not...

Deliverer schrieb:

Why should an air conditioning system reduce a building’s energy efficiency? They are subsidized by BAFA because they IMPROVE the energy efficiency of buildings.

I can only speak from my recent experience that just installing the air conditioning would have destroyed our KfW standard. We had exactly this problem 8 weeks ago.
The energy consultant recalculated the building using a different DIN standard under this condition (at least that’s how I understood it), and initially, it was NOT sufficient; but at some point/somehow it was okay. According to him, this recalculation was absolutely necessary.