Passive house as a logical consequence? Are there counterarguments?

Good evening,

first of all, it must be determined what exactly is meant by Passivhaus (PH). What has so far been found under this term - when a municipality makes PH a condition for purchasing land - resembles a low-energy house, but not a true PH. A true PH, for example, does not have a conventional heating system in operation, but an air-to-air heat pump; rather expensive windows are also one of its characteristics.

The additional costs mentioned here so far, PH compared to KfW 70, are therefore not accurate. 40% are realistic.

Rhenish greetings from the road
Building expert

So with us (Saxony), a turnkey house (120m²) costs between €160,000 and €180,000 (Energy Saving Ordinance standard). I currently have an offer for a passive house of this size for €220,000. That would be €40,000 more. But since I get €50,000 from the KfW at 0.75% interest and another €50,000 at 1.55% interest plus an additional €5,000 repayment grant and further subsidies for solar and battery, I have a saving of about €30,000 over 30 years. So I would still have additional costs of €10,000-20,000. However, since I need about €800-1,000 less per year for heating and with the photovoltaic system on the roof and the battery, I even get money back for electricity because I can feed into the grid, I save another €1,000 per year for electricity. That is €2,000 savings per year. So after 10 years I would have recovered the total additional costs and from then on would only make a "profit" compared to the standard house. Sure, maintenance costs here and there and so on, then let’s say 15 years. But I also have maintenance costs for a heating system, which I don’t need for a passive house, and I have to replace a boiler after 20 years anyway. My calculations are correct, right?!

1000 € less for heating? I believe most new buildings today with 120 m² don’t consume 1000 € worth of heating per year... your battery probably lasts exactly 10 years then - you can buy a new one with the savings

Ok, then 800€ for heating and hot water, I think that is realistic for a standard Energy Saving Ordinance house?! Then it will be 15 years as written. I checked again, it is even an energy-plus house for which my offer is. So, as the building expert already said, without heating. I have an acquaintance who built with this company 3 years ago. He needs 3 wheelbarrows full of wood per year for heating. His photovoltaic system produced 10,000 kWh per year, he used 3,000 kWh himself, fed 7,000 kWh into the grid. He had to buy 2,000 kWh when the sun didn’t shine and the battery was empty, resulting in a net profit of 300€.

But since I get €50,000 from KfW at 0.75% interest and another €50,000 at 1.55% interest

Why twice for KfW? Or do you mean the 123 program for the first KfW loan? You have to deduct that again (that would be the better one), as you get this loan for every new building (if you want it).
And the subsidies are state-specific.

Regards, Yvonne

Right, the 124 program is available for every new building, that’s the program with 1.55% interest, then it’s about €5,000 less savings and just amortized after 20 years, if energy prices were to remain the same, which they probably won’t. So I’m probably heading back towards 15 years after all...right?!