ᐅ KfW85 vs. KfW70: Is the Higher Cost Worth It?

Hello, a preferred developer of mine generally builds houses to the KfW 85 standard. To upgrade to KfW 70, there is an additional cost of almost €8,000. This includes better insulation and a 300-liter (79-gallon) hot water storage tank combined with photovoltaic panels. A friend mentioned that the extra cost is not worth it because the long-term savings are too small. My argument about the low-interest loan of €50,000 at 1% was only met with a tired smile, as interest rates are very low anyway. I would be interested in your opinion on this...

I think the KFW 70 standard is quite reasonable when it comes to insulation. After all, you are building for yourself, not for someone else. Whether you decide to go with the KFW 153 standard is entirely up to you. If you get good terms from your bank, you can certainly forgo it, but the standard itself is by no means unreasonable.

Regarding the heating system, KFW 70 does not necessarily require a gas condensing boiler combined with photovoltaic panels. There are also alternatives such as air-source heat pumps or ground-source heat pumps with surface collectors or the more expensive deep drilling option. If the budget allows, I would recommend installing a heat pump.

Häusle77 schrieb:
..,and a 300-liter (79-gallon) hot water storage tank installed with photovoltaic panels. ...

Or do you mean a solar system that heats the water on the roof?! That would usually be the standard offer from the builders.

There is often a misunderstanding that you only pay money for the project, but you also get something in return. A general contractor once told us, "With KfW70, you can skip the ventilation system and save €8,000," as if I’m building my house just to get the cheapest possible home and to satisfy annoying regulations. You do receive a benefit for your investment—even if it’s just a wall that’s 1°C (1.8°F) warmer. Whether this pays off financially is another question. I believe there was a study a few years ago that crowned KfW70 as the most cost-effective standard.

As previous speakers have already mentioned, you don’t just get “cheap” money but also added value through sustainable savings (insulation, etc.).

The interest savings are quite straightforward. What do you pay for the main loan and what for the KfW loan?

For example, €50,000 (about $54,000) at 2% versus €50,000 (about $54,000) at 1% means a difference of 1% = €500 (about $540) per year in interest savings. Over 10 years, that adds up to €5,000 (about $5,400) plus the effect of compound interest.

If you look at it that way, you might as well build to KfW 55 standard. Viebrockhaus offers this as a standard option, and I also wanted to schedule an appointment with them...