KfW Efficiency House 70 (Energy Saving Ordinance 2009)

Hello,

is it possible to achieve a KFW efficiency house 70 (Energy Saving Ordinance 2009) with a massive construction (Poroton bricks 17.5cm and 16-20cm insulation) and triple-glazed windows?:confused:
The heating would be an air-water heat pump.

Regards relex

Hello relex,

You always have to see it as a "complete package" of measures.
That means you have to sit down together with your architect here.

However, I would only use an air heat pump starting from a Kfw55, if at all.

Best regards

Hello,

why?

What would you install?

Regards relex

Hello,

air heat pumps are good if they meet the BAFA efficiency criterion (seasonal performance factor 3.5).

In practice, the seasonal performance factor is usually always below the calculated value, as the execution and user behavior also play a role here.

So we will probably be talking about an actual seasonal performance factor of 3.0.

Currently, the cost of OIL corresponds to a seasonal performance factor of 2.6.
So not a very comfortable margin.

A DV heat pump usually has a seasonal performance factor well above 5.0 and requires a pump for the eliminated 3rd circuit and relatively little collector area.
In new buildings from 1:1 upwards.

I would definitely have your planner calculate the alternative here.

The lower your heating load, the smaller the gap will be.

Best regards

@parcus I think you are mistaken. kfw55 does not exist, I believe it was called that earlier, now it is called kfw70, which is the next best standard after the Passive House. Or am I wrong?

@relex We are currently planning a Kfw70 solid house with a heat pump. In combination with a heat pump, this standard is not particularly difficult to achieve. For us, it will be 24 cm masonry made of unipor plan bricks W14 (thermal conductivity 0.14W/mK) with 14 cm insulation. According to our architect, 10 cm insulation would already be sufficient for the kfw70 standard. However, with 17 cm masonry, you would probably need more than 20 cm insulation. Why not use 24 cm masonry?