Vestaxx window heating - experiences?

Well then, don’t YOU worry about delivery capability and the shortage of skilled workers and the resulting rising craftsman costs – maybe others do.

What does an honest calculation without photovoltaics mean? I compare systems at the same purchase price. And without photovoltaics, the calculation doesn’t add up. I have already emphasized this several times here. You can only cut costs if you cut the same amount on the other side of the equation.

Then only 10 kWp fits on your system – then treat yourself to a large battery with the remaining money and increase your degree of self-sufficiency or spend the money on the bathroom or the kitchen or a nice vacation.

I have also pointed out several times that heat pump plus photovoltaics is of course great, but also about 50% more expensive. Whoever can afford it – please feel free. But most building families have no reserves left and must make sacrifices.

I just wrote something about IR panels on the wall today. We are in the infrared association and I also support the technology. Therefore, I will not specifically discuss the differences to window heating.

Regarding your calculation -> 250 €/piece is rather very low or you mean hardware from the hardware store from China – then fine. The 10,000 € for the heating glasses are viewed as a lump sum and are rather on the high side. I just didn’t want to be considered too cheap here, but it still pays off.

You can place the panels freely and if the furniture is rearranged, you simply move them – you’ll find a power outlet ;) What bothers you about the windows being fixed? What kind of argument is that? The window surface is the coldest surface in the house and with us, it becomes the warmest surface -> best comfort class (also posted just today).

The question about the bathroom is again constructive. Here you can’t do without an additional heater (towel radiator or heated mirror, etc.). This is part of our consulting service for every project. We don’t just sell heated windows, but advise the building families in advance, do sizing and later also the individual wiring diagrams.

By the way, the heat pump with underfloor heating in the bathroom usually isn’t enough due to the higher comfort requirement. There is always an additional heater. That way your niche is well supplied too.

What does an honest calculation without photovoltaics mean? I compare systems at the same purchase price. And without photovoltaics, the calculation doesn't work out. But I have already emphasized this several times here. You can only cut out if you cut out the same thing on the other side of the equation.

Then only 10 kWp fits on your roof – then treat yourself to a big battery with the remaining money and increase your degree of self-sufficiency or invest the money in the bathroom or kitchen or in a nice vacation.

Exactly what everyone else says. A heating system has to sell itself through heating, otherwise the argument is weak. I would find it honest if you said... "with 130 sqm and 25 kWh/sqm you only have a heating demand of 3200 kWh/a anyway, so efficiency is not important. You only recoup the additional cost for a direct heating system after x years." That is your argument – the low initial investment – and that can be completely sufficient. Air heating is used more frequently nowadays. Two of our future neighbors have it, and my cousin as well. But you only touched on that briefly, you much prefer to argue for buying the gas station. Photovoltaics is something you either do because you think it pays off or not (or because you are obliged to in BW). And since little electricity comes from the roof in winter anyway, a very high energy consumption is not an argument for photovoltaics, especially not if the stated size does not fit on many roofs. And a bigger battery is not a substitute for more installed capacity in winter either, because you first have to be able to fill it. Especially when your own consumption is high due to an inefficient direct heating system.

Regarding your calculation -> 250 €/piece is rather very low or you mean hardware from a hardware store from China – then please. The €10,000 for the heating glass is viewed as a flat rate and rather overestimated. I just didn't want it to appear too cheap here, but it still pays off.

I looked on the internet for a few minutes and saw prices between €100-220 for 600W panels. Much more expensive ones did not initially show up. But with that price difference, there is still plenty of room for upward adjustment.

What bothers you about the windows being fixed?

I can mount a panel wherever I want. In the bathroom example, for instance, I would mount it at the bottom of the plan next to the mirror so that it can shine into the toilet and shower areas. You can't do that with a window. And if I design windows so that they illuminate the room well, then the tail is wagging the dog.

The window surface is the coldest surface in the house and in our case becomes the warmest surface

How cold is a modern triple-glazed window with a warm edge still? How warm is the wall next to it? These are serious questions because I don’t know the answer. But I am sure you cannot simply adopt the old logic “there’s cold at the windows, therefore radiators go underneath” without backing it up with numbers.

Of course, this discussion started incorrectly from the perspective of a window heating builder. The correct question would have been: "Should I invest more money in energy saving or in energy generation?" That would have excluded half of them, but with the other half, the discussion would have continued. The next question would then be: Should I put my money into efficient heat generation or into efficient energy generation? Again, half would remain. With them, one discusses the possibilities of saving money in system technology in order to invest it in energy generation. After that, the still remaining different heat transfer systems are put up for discussion (i.e., electric underfloor heating, infrared panels, or simply window surface heating). When that point is reached, the advantages (or disadvantages) can be debated, but one is talking to likeminded people, and not to the majority who have already gotten off the bus.

Exactly what everyone else says. A heater has to sell itself through the heating, otherwise the argument is weak. I would find it honest if you said..."with 130 sqm and 25 kWh/sqm you only have a heating demand of 3200 kWh/a anyway, so efficiency is not important. You only recover the additional costs of a direct heating system after x years." That is your argument - the low initial investment - and that can be completely sufficient. Air heating is now installed more frequently. Two of our future neighbors have it and so does my cousin.
But you only touched on that briefly, you much rather argue for buying the gas station. Photovoltaics is something you either do because you think it pays off or not (or because you are obliged to do so in BW). And since little electricity comes from the roof in winter anyway, a very high energy consumption is not the argument for photovoltaics, especially if the size mentioned doesn’t fit many roofs at all. And a larger battery is not a substitute for more installed power in winter either, because you first have to be able to fill it. Especially if your own consumption is high due to an inefficient direct heating system.

I looked online for a few minutes and saw prices of €100-220 for 600W panels. Much more expensive ones didn’t appear at first. But there is still plenty of room to move up with that price difference.

I can mount a panel wherever I want. In the bathroom example, for instance, I would mount it at the bottom of the plan next to the mirror so that it can radiate into the toilet and shower area. That doesn’t work at the window. And if I design windows so that they radiate well into the room, then the tail wags the dog.

How cold is a modern triple-glazed window with warm edge? How warm is the wall next to it? These are serious questions now, because I don’t know the answer. But I am sure that you can’t simply adopt the old logic “windows are cold, so radiators underneath” here without underpinning it with numbers.

... A heater has to sell itself through the heating ... -> what kind of argument is that? :mad:
We are not selling a heater itself but a window heating system in combination with photovoltaics and a heat pump.

You start well with your calculation ... = 3200 kWh - but then you stop. Why don’t you continue calculating and publish it here – just as I did. Then let’s look together at what comes out.

You don’t understand our system and you keep pointing out again and again that photovoltaics do not provide enough for heating in winter. Yes - yes - yes - and yes again!

The hint about the battery, on the other hand, is good – I’m also not a fan of batteries in our example because they actually aren’t economical and are no good in summer and winter. I can gladly explain more, but I’m supposed to keep it brief. :confused:

What you don’t consider is that house electricity must be purchased all year round (about 3,000–4,000 kWh) and the heat pump doesn’t add a damn thing to that. Yes, the heat pump may save about 3,000 kWh per year – but in return the photovoltaic system generates about five times that annually and a large part of that is used directly. Calculate it yourself and you will be amazed! Or are you afraid to work yourself into a corner? ;)

Go ahead and buy the cheap IR panels and be happy with them – with that you’re already on what you call an inefficient heating system (direct electric heating) and away from the heat pump -> congratulations! So far so good. Then skip the windows – that’s okay too. ;)

Placement of radiant heaters:
I’ve already written that an additional heater is always needed in the bathroom. You can place that wherever you want then.

So – now to your seriously meant questions (should I not take the rest of your statements seriously)?:oops:
Depending on the insulation, the wall is about 19 degrees Celsius and the glass 18 degrees Celsius (of course, that depends on the outside temperatures and the room air temperature). Buy yourself an IR thermometer (about €15) and measure it yourself. A normal room (not the bathroom) has about 21 degrees air temperature. With radiant heating, the room air temperature can be lowered by 3 degrees without any loss of comfort. This can save 18% heating energy (source: scientific studies).

Maybe one gave in to the temptation to generate interest with the buzzword "Energiesparen". In this case, that is not even true. If one had used the less catchy phrase "Energieerzeugung versus Energiesparend, was macht mehr Sinn", the petty recalculations would have become unnecessary. By the way: Twenty years ago, I thought it was a good idea to water my garden with a 12cbm cistern. The investment was 6,000€. For a quarter of the money, I could have drilled a well. Rainwater discharge fees are 1.50€/sqm of sealed surface x 200 sqm = 300 € for the roof area. Savings from the well: 4,500€. Annual discharge fee: 300 €. Payback period: 15 years without interest. Clever??

I just don’t understand how anyone can say heat pump OR photovoltaics.

You should simply always do photovoltaics and then decide whether you want to heat with air-water heat pump, ground-water heat pump, direct heating, etc.