ᐅ Costs of a Blower Door Test?

Good morning,

I have a quick and simple question...

We are building a KfW70 house through a developer – who covers the costs for this test? Doesn’t the developer have to guarantee that the house built meets the KfW70 standard and prove it with such a test? Regardless of whether financing is through the KfW bank or not.

Good luck & thank you!
Gatho

So in our case, the builder handled it even though nothing was specified in the contract... Pure goodwill, in my opinion.

We are building a KFW 55 house, and our developer is also covering the costs. If I understand correctly, two tests are conducted. One has already taken place before installing the drywall panels. The second will be done once the external insulation is applied.

I also believe that if I buy a KFWXX house, the test should be included as part of the process.

When I buy a sack of potatoes in a store, I expect a bunch of carrots to be included as well. So, what now?

What is contractually agreed upon?

To comply with the energy saving regulations, a blower door test is only mandatory in certain cases (when a controlled residential ventilation system is installed and accounted for in the energy saving documentation, or when an air change rate of 0.6 1/h is assumed). Therefore, if the building is constructed “only” according to the energy saving regulations and the test is not explicitly part of the contract, I don’t see any reason why it should suddenly be included.

As my predecessors have correctly pointed out, the execution and cost coverage of the blower door test by the builder is not mandatory and must be agreed upon individually in each case.

And if someone buys a "KfW55 house" from the developer, but the contract says nothing about the blower door test, is it included or not? According to the KfW information sheet, "the airtightness of the building envelope must be verified by measurement," so the developer needs proof of performance.