Advantages of KFW 40 Plus in General

Do you have a layered buffer storage or which configuration do you have?

5.4 kWp photovoltaic system on the roof, and an LG storage with 8 kW in the basement.

In addition, an air-water heat pump. The house is 40+ years old.

On 5.4.19:
Production: 18.46 kWh
Of which fed into the grid: 8.55 kWh (46%)
Consumption: 14.16 kWh
Of which purchased: 4.24 kWh (30%)

We only have one meter, so heating electricity + household electricity. And quite a few consumers. SBS refrigerator, the dishwasher was programmed for 12 o’clock, chest freezer, controlled residential ventilation, circulation line...

In general, it is always a case-by-case consideration. For us, the difference between 55 without basement and granny flat and 40 WITH basement and granny flat was almost exactly 100,000 €. The basement is a "white tub," fully insulated, included in the ventilation, livable ceiling height, partly floor-to-ceiling windows, partly spatially separated, own bathroom, underfloor heating. So an expensive basement.

Presumably, just the extra building services and insulation would have cost 20-40 thousand + the 18k € for the photovoltaic system.

We can offset this against two times 15k € repayment subsidies from the KFW and the tax deductibility of the granny flat over 50 years. Or until the tax office shuts it down for lack of seriousness in the rental :P

You can look at this from so many angles that you always end up with something different. It already stands and falls with the offers, which can differ by 100%. We didn’t do the whole KFW thing. The conditions were worse than a normal loan, which would have partially nullified the repayment grant again; on top of that, you would have had to pay for an approved construction supervisor and had administrative effort – maybe in the end it would have been 2-3k€ extra, but that doesn’t really matter with these sums. Independent of that, we have (and would again) still install all that stuff: controlled residential ventilation, photovoltaics, heat pump. Whether KFW then pays off, you just have to recalculate.

Our shell construction in passive house standard cost about 20,000 euros (2017) more than KFW 55. Mostly the insulation. With the same provider, the exactly same equipped house. The shell construction is fairly balanced again due to the elimination of the underfloor heating. We have a Stiebel Eltron/Tecalor trial system.

With your additional costs of 19,500 euros you won’t make it. The storage probably still cannot be reduced. Especially since your additional costs already include things that are not necessary for the energy saving ordinance.

Take a look at Autark with Passive House. For more than a year now, all values have been broken down precisely there. Consumption, purchase, feed-in. Presumably, you won’t find a second house with these values, since location, lifestyle, etc. change everything. For that, the numbers are not nicely calculated by sellers.

An energy saving ordinance house is not bad. Not long ago, that was a KFW eligible standard. Financially, it does not pay off at the moment (say those with passive houses).

What happens if the next stage of the energy saving ordinance comes and/or the building boom declines? That’s a crystal ball question.

I find the comparison with Tesla quite fitting.

Not worth it. Nowadays, anyone who wants to build with insulation and controlled residential ventilation can take advantage of the KfW subsidy without significant additional investment. For those who want to build monolithically without anything, it is not worthwhile.

In the case of a sale, it might be advantageous if the house, for example, also meets future energy-saving ordinance standards, but I wouldn’t count on that now, because whether anyone will ever pay even 1€ more for it is questionable.

For us, the good insulation of the KfW55 standard combined with a gas heating system is worthwhile due to a very open construction style (open bathroom on the gallery...) and the increased heating demand of the occupants. Otherwise, we would probably be heating ourselves poor in the long term. But who has an open bathroom anyway... I actually don’t know anyone. So we are not normal anyway.

Always keep climate change in mind. Summers are getting hotter and hotter, and insulation works very well in this direction too.

That the KFW loan offers better conditions is also a myth.

Currently between 0.75% and 0.9% depending on the term. Then show me a comparable offer from the open market... (Plus the subsidy "given" depending on the KfW standard, 5000-15000€)

So I built a house last year, although only a small one with 136m², the surcharge from KFW55 to 40Plus was "only" 15k with my provider, for which there was thicker insulation, photovoltaics + storage in minimal design, each 3.6KW(h).

I haven't had to heat for 3 weeks now, thanks to heat recovery.

Hot water, thanks to the good weather since February, is heated to 70° at noon via photovoltaics in the 300l heat pump/heating rod combination unit, which can also last more than a day without sun.

The degree of self-sufficiency has been over 80% for the last 2 weeks and I still have to feed electricity into the grid.

There are 4 of us with 2 small children, so daily at least 1 washing machine + (heat pump) dryer and at least 1 dishwasher run for free.

So for me it has paid off or am I overlooking something?

It can be a mistake to first set the standard and order accordingly. KfW houses (especially 55) can also be planned on the edge: air-water heat pump for primary energy and a more precise calculation of thermal bridges that only takes place on paper. I would first plan the house and building services economically and ecologically sensibly. Use insulation where it is cost-effective or where you will never get access again. A well-planned heating system and an energetically sensible layout bring, in my opinion, more than the next better insulation standard! Only at the end would I look at how far you are from KfW 55 or 40. We only built according to the Energy Saving Ordinance but consume less than most KfW 40 houses. In retrospect, I admittedly would have built to KfW 40 without Plus because we are not that far off with the insulation and technology we ultimately used. During planning, we only thought about KfW 55, and at that time the subsidy was too low for our own effort.