Vestaxx window heating - experiences?

But such a large photovoltaic system is certainly expensive.

It is not the size of the photovoltaic system that is the limiting factor, but the issue of storage.

h No, the calculator does not lie: 23,000 x 3.5% = 805,- x 20 years = 16,000,-

Please read up on the basics of interest calculation. At this level, a discussion makes no sense.

Please read up on the basics of interest calculation once. At this level, a discussion makes no sense.

I find the discussion surprisingly soft anyway for such a “Hard topic”.

Do you really believe that an electric direct heater (of any kind) has a future? I would bet that this type of heating will be banned in the not too distant future and all the discussions circling around here will be settled. The energy consumption is simply too high. Maybe it will still be acceptable as an emergency solution in passive houses. But nothing more.

I believe there will be differences, assuming that the regulations are pragmatic and not ideological. I also find it hard to imagine a simple electric heater in the sense of a fixed installed fan heater in the future. For storage heaters, I even see not such bad chances, but no longer as day/night electricity but rather as peak load/off-peak load. The energy production of the future will fluctuate much more than it already does today and much more than it did decades ago. Since storage is difficult and expensive, it would by no means be a bad approach to partially balance the fluctuations using storage heaters. With infrared heating, etc., this doesn't work well since the storage capacity is lacking. On the other hand, regarding operating costs, it is questionable for which houses this makes sense. The EH40 can manage well without heating for a few hours even without storage. Old buildings cool down faster and would benefit more from storage, but 20,000 kWh of electricity is simply way too expensive.

Or, we build a house that can also be operated sustainably and with low running costs by other people's children. A house where the annual performance factor mitigates every price fluctuation of energy costs by a factor of 4-5. Where you also buy security for cheap operation for the next 50 years (certainly not with the first heating system). On top of that, you have pleasantly warm feet and a floor where children can play without having to lay carpets or blankets everywhere. Where it’s simply cozy, and in summer you can even cool down using the heat pump’s cooling function.
The normal single-family house construction should be significantly more comfortable and safer in the long term with a heat pump and underfloor heating.
Although, of course, that may also depend on individual life circumstances.

Can you please tell me where to buy your crystal ball? I need a new one because mine doesn’t work properly. :eek:

About 50 years ago, my parents wanted to build or rebuild the two-family parents’ house (farm) to be future-proof, and they did. But the money was only enough for modern solid construction with large double-pane insulated windows, shutters, an oil stove heating system, a bathroom electric heater, and central electric hot water for bathroom and kitchen.
In 2000, my brother took over the house and modernized it again to be future-proof (partial insulation, brand new oil heating, radiators, pipes, etc.). With a super modern oil heating system because an air heat pump was not possible or much too expensive...
In 2022, the house is sold and is supposed to be rebuilt to be future-proof again, including a completely new much larger second bathroom with a new heating system: heat pump + photovoltaics + firewood...
Since 2015, my brother has had a new old single-family house that was built in 1984 to be future-proof with super insulation and oil heating. The single-family house was gradually rebuilt by him to be future-proof: 20 cm external thermal insulation composite system + new underfloor heating + air heat pump but (still) without photovoltaics.
Since I know an incredible number of "future-proof" projects from the last 50 years in the area, I don’t believe that this works.

Here the answer is even much simpler. Yes, you are miscalculating.
Interest would be €9,013, but can be completely ignored, since the increase is also not taken into account on the electricity.
If it is also around 3-4% p.a., it balances out.

However, your €9,013 is not correct with 2% repayment and 3.5% mortgage interest; with a fixed rate, it comes to about €12,300.
And after 20 years, there are still almost €10,000 left on the loan.