ᐅ Building to the Energy Saving Ordinance 2016 or to KfW55 standards

Hello,
I have been following the forum for a few weeks and have an important question before signing the fixed-price contract.

I am building a turnkey city villa (catalog home) with an air-to-water heat pump, living area approximately 118 sqm (1272 sq ft), and the planning contract has already been awarded. The general contractor offers a standard build according to the Energy Saving Ordinance 2016 and charges an additional approximately 13,000.00 Euro for upgrading to KfW55 standards, which includes improved insulation under the slab and ceiling above the upper floor, as well as exchanging Poroton T12 bricks for Poroton T9 bricks.

The subsidy for KfW55 is 18,000.00 Euro, and the subsidy for KfW55 EE is up to 26,250.00 Euro.

If I build to KfW55 standards, I expect additional costs of 13,000.00 Euro for the improved insulation, 2,000.00 Euro for the energy consultant, and 10,000.00 Euro for a decentralized ventilation system. That would use up the subsidy entirely. According to my research, the annual savings in electricity costs for the air-to-water heat pump compared to the Energy Saving Ordinance 2016 are only about 100.00 Euro per year.

Of course, the higher market value potentially achieved when selling the house speaks in favor of KfW55, but I do not plan to sell.

Otherwise, the savings compared to the Energy Saving Ordinance 2016 to KfW55 are only marginal. Additional ventilation also brings maintenance costs. With KfW55, the building envelope is sealed so tightly that fresh air must be supplied again via fans. You pay for the increased insulation and then for the ventilation needed to compensate. Houses built to the Energy Saving Ordinance 2016 are not as airtight and do not require ventilation systems.

I am opening this topic for discussion.

I look forward to hearing the various opinions.

Regards, Raiweired

Houses built according to the energy saving ordinance are just as airtight as KfW 55 standard and require ventilation. This can be window rebate ventilation, decentralized or centralized controlled residential ventilation, or someone regularly opening the windows.

Raiweired schrieb:

Other than that, the savings compared to the 2016 Energy Saving Ordinance to KfW55 are only marginal.

Raiweired schrieb:

Houses built to the 2016 Energy Saving Ordinance are not as airtight and do not require ventilation.

Do you have to install a mechanical ventilation system for KfW55?
The house built to the Energy Saving Ordinance is just as airtight. You won’t notice the difference. If you don’t ventilate a house built to the Energy Saving Ordinance, a) mold may also develop, and b) it will always smell like a cage for wild cats.

Raiweired schrieb:

Sure, one argument for KfW55 is the higher resale value that could be expected, but I don’t plan to sell.

No, but you want to live there for a long time and participate as little as possible in rising electricity costs. Therefore, minimizing electricity consumption (heating costs) should also be a goal.

Raiweired schrieb:

An additional ventilation system even causes maintenance costs.

Which ones? Just go to a filter shop and buy suitable filters for the systems (often also available to cut yourself). That reduces maintenance to about 10€ per year and a bit of effort.
What I find much more important, and what you don’t even mention, is the increased comfort, which you really cannot express in euros. That should be the main focus.

Thank you very much for the responses.

So, the energy saving regulation and KfW55 standard result in the same level of airtightness. Then, the additional insulation and the switch to T9 (thermal insulation standard) provide more insulation and therefore reduce the electricity consumption of the air-to-water heat pump?

It is not yet decided whether a mechanical ventilation system with heat recovery is required for KfW55. I approved the house design today, and according to the general contractor, the energy consultant is scheduled to check next week if a mechanical ventilation system is necessary.

It is possible that KfW 55 also includes a better insulated roof... This could also be beneficial as protection against heat.

Yes, the additional cost of 13,000.00 euros for KfW55 includes improved insulation under the foundation slab and the ceiling above the upper floor, as well as the replacement of Poroton T12 blocks with Poroton T9 blocks. The ceiling above the upper floor will be constructed as a precast hollow-core slab.