ᐅ Planning a Single-Family Home Construction – Building Energy Act 2023

Hello everyone!

We are currently in the planning phase for a solid single-family house with a living area of 154m² (2 full floors), 77m² (830 sq ft) of usable basement space, and a total enclosed volume of 1010m³ (35,670 ft³). Due to ongoing site development work, construction is expected to start around August 2023.

In August, we signed the turnkey construction contract based on the 2020 Building Energy Act standard. Since the KfW funding programs were put on hold, we honestly didn’t focus much on energy efficiency, assuming the standard would be sufficiently high. Now, during further planning, we came across the upcoming changes to the 2023 Building Energy Act, which, as far as we understand, have already been approved by the Federal Council?!

The planned specifications are:
- District heating as the energy source
- Triple-glazed windows (U-value 0.6 W/m²K)
- Exterior walls made of 36.5cm (14 inches) brickwork (0.09 W/mK)
- Central mechanical ventilation with heat recovery, including the basement
- Basement with a 25cm (10 inches) thick floor slab and 25cm (10 inches) concrete wall thickness plus 12cm (5 inches) perimeter insulation (0.035 W/mK)
- Roof with 20cm (8 inches) cavity insulation (0.035 W/mK) plus 60mm (2.4 inches) wood fiber board insulation above rafters

The necessary changes to achieve a “funding-eligible” KfW55 house are currently priced at around €15,000. Honestly, I would have preferred to invest that money in a photovoltaic system, if it really was available.

As far as I understand, the 2023 Building Energy Act changes do not affect the building envelope requirements but rather the “primary energy demand.” Does anyone know if these are mainly calculation changes, or do the new rules actually require investments equivalent to those for a KfW55 house? Are the anticipated energy savings really about 15% compared to a KfW70/2020 Building Energy Act standard, making the extra costs definitely worthwhile, or is this just wishful thinking?

We are a bit annoyed that the company did not inform us about these expected changes and the resulting clear cost increase before signing.

Thanks very much for your opinions!
Best regards,
Hansi

Your general contractor surely has a professional who can prepare the thermal insulation certificate for you, which you then need to submit to the building authority before starting construction. Why don’t you ask your general contractor?

Of course we're asking him; I just wanted to know if anyone is familiar with this. The amendment will also affect everyone who is currently planning and building next year.

Hansi H. schrieb:

Of course we are asking, just wanted to know if anyone is familiar with it. The amendment will affect everyone who is planning now and building next year.

We have been building since October, and I believe the amendment does not apply to us. Therefore, I can’t say much about it. Most likely, a gas heating system alone won’t be sufficient.

I found the following on the building energy law website:
“The Building Energy Act came into effect on November 1, 2020. A further amendment will take effect on January 1, 2023 (reducing the allowable annual primary energy demand in new buildings from 75 percent of the reference building to 55 percent).”

To me, this sounds like the EH55 standard will become mandatory.

As far as I know, the new regulation corresponds to EH55 and applies to everyone who receives their building permit / planning permission from next year onwards. You will probably have to accept a certain price increase.

However, I would be more concerned about this:

Hansi H. schrieb:

Construction is expected to start around 08/2023 due to ongoing site development work.

We signed the turnkey construction contract in August.

What is the situation with your fixed price if there is a year between signing the contract and the start of construction? How much flexibility do you have if the site development is delayed?

The offer is linked to the construction price index. For us, this was the most transparent solution. However, we have a contract withdrawal option if we pay for the input and factory planning.