Vestaxx window heating - experiences?

Ah, it was obvious that only things that move break, how come no one else thought of that before! I need to explain that to my SSD, which died a few days ago!

Yes, absolutely right, comparing heating systems only makes sense if you add photovoltaics to one and not to the other. It would be super unfair if the heaters had to heat efficiently on their own in the comparison.

Yes, this also makes total sense now, the hundredth time I read it, because banks and loans unfortunately haven’t been invented yet, so photovoltaics + heat pump is absolutely impossible.

Scroll up and read.

What was it, not everything that limps is a comparison?! Show our arguments and calculations to the energy consultants and professors. Even if it’s not their field, they will hopefully be able to understand it.

Also just scroll up a bit or go back a few pages and read/recalculate. Spoiler: in that example Vestaxx was over €30,000 more expensive.

Comparing an SSD – a highly complex electronic component – to a stupid coating is ....

With you, I give up! If you want to compare a Porsche with a Golf, go ahead – but that’s not fair.

And yes – of course there are loans (they’re very attractive right now), but they also have to be paid back. Loan amount + interest -> every bank is happy and the building family will have to move out eventually if they can no longer service the loans.

So showing your arguments to the energy consultants and professors – you do that yourself. What would it bring me?

Sorry – I can’t go on with you anymore – let’s just leave it at that.

I googled a bit on the topic. The "inventor" of the system apparently comes from the field of thin-film photovoltaic module development and has experience sputtering and heating float glass (yes, right, no ESG) with metal without getting the expected stress cracks. But despite the embedded (if I sputter a surface, is that then embedded?) metals, glass can still break or the only a few micrometers thin layer can get interruptions due to expansion/contraction (that was also an argument for a possible defect of the underfloor heating pipes). Reliable figures have so far been withheld from me. Whether due to lack or intentionally, I don't know? But they might still come ;)

So – first of all, I am not the inventor, but whatever. Nor do I have the experience, but the glass industry does, which has been producing this layer for decades. And yes, it is a sputtered layer, as with all thin-film glasses (by the way WITHOUT ESG). And now comes our experience, because we have experience from approx. 2,000,000 m² of thin-film modules completely without stress cracks. And that in use cases where a chimney cast a severe shadow on the modules. Well, Kati, and if you’re reading this now, you’re looking through exactly such a layer, and if it had stress cracks, it would be dark. Then all the thin-film modules out there that have been generating their energy for over 50 years... What reliable figures do you want from me – open your eyes. If you have no clue and have only googled dangerous half-knowledge, you should simply keep your mouth shut. I’m slowly reaching the point where I’m considering whether I should continue to struggle with people with dangerous half-knowledge. Because for those who are actually interested, it must be a horror to read such posts from anonymous people. Who knows which interests are being pursued. My interests are open and known, because I am not anonymous. If someone really wants to hear about genuine experience here, we are happy to connect them with our customers all over Germany. THOSE answers are also not anonymous and come first-hand.

Finally, things are moving forward here. Luckily for you, I’m not allowed to go out for at least the next 5 days and am therefore on call for more invoices and arguments.

The heat pump saves about 2000 kWh annually in a new build house with approx. 3,000 kWh HWB.

Oh, what happened there? Did our house shrink? We came from 4500 kWh, didn’t we?

Your table is great – thanks for that. It’s very clear that the annual performance factor plays a role and that with an annual performance factor of 5, we are roughly break-even after 15 years. What’s unfortunately missing are the maintenance costs – zero for us and for the heat pump? 200 € annually? I don’t know right now.

Then also calculate against the domestic hot water heat pump. The 200 € seems about right, although most homeowners probably won’t carry that out after the warranty period. The heat pump reports any errors itself, and otherwise, maintenance consists of looking inside the heat pump and nodding importantly. Possibly the annual performance factor is read off as well.

And now again – I know it’s annoying – the consideration that the customer is clever and chooses security.
By purchasing a photovoltaic system (with the saved investment costs), he does exactly that. Photovoltaics are good – we all agree here.
But then we can forget your table again and need a new one that takes this into account.
The customer largely makes himself independent of the certainly rising electricity prices with a large photovoltaic system.
That’s what moves people.

Sometimes I have the feeling that you don’t have photovoltaic yourself, which is supposed to make you independent in winter. With 9.5 kWp, from November to January I got less than 100 kWh per month. Nothing comes in winter and you have to buy power for operation. My “plus energy house” with 6–8 ct in summer doesn’t help me at all! That’s exactly why we have all the discussions about dark doldrums in politics.

Put another way. I can easily hold our material for the heating technology of an entire house in one hand.
For water-based systems, you already need a strong forklift for that. Does that make sense?

"... Of course, you also have to look at Scope 3 Downstream and not just Cradle to Gate... "
Who, please, among the regular people who want to inform themselves about window heating, understands a sentence like that?
Write understandable German or just leave it out.

Just say outright that you have no idea about greenhouse gas emissions and their accounting according to the GHG Protocol.

Sorry, it’s the worldwide (industry) standard for determining sustainability. Doesn’t change my assessment of window heating as a massive environmental sinner. It’s really time for your master’s thesis because doing your own calculations is indeed very enlightening and, in your case, unfortunately disastrous.

And it doesn’t help that you can hold your coating elements in your hand. Heating usage unfortunately pulls the CO2 footprint of our sample house down by at least 16–20 tons of CO2 over time. For that, the heat pump owner can nicely fly to New York a few times for a hotdog.

A fundamental question: how are the 92/95% efficiency rates determined? That’s the efficiency for the heating glass, right? What I didn’t understand is how the heating output from the 230V mains voltage is throttled. For that, a transformer etc. is required, isn’t it?

I am still waiting for a calculation that does not come from a user. Their effort is to be respected - but in my eyes, the obligation to provide is clearly on the other side...

No offense intended, but this should be representable in a table, right? Maybe I just overlooked it.

I am still waiting for a calculation that does not come from a user. Their effort is respected - but in my eyes, the obligation to provide is clearly on the other side...

No offense, but this should be representable in a table, right? Maybe I also overlooked it.

It won't happen. The startup founder doesn't want to confuse customers with too many numbers. It would only confuse them. The customer wouldn't be able to make use of it anyway.

With photovoltaics, I know very precisely what comes out over the lifetime. -> Security

No, you don’t know that. You can have a rough idea if you have a full feed-in system. Then the feed-in tariff is fixed for 20 years and after that you only have the feed-in to consider, with questions about how long the system ultimately lasts and spare parts like inverters as unknowns.
But your calculation always also includes a significant portion of self-consumption, and with that, you are additionally extremely dependent on the electricity price. What comes out in the end is anything but certain.

Oh, what happened there? Did our house shrink? We are supposed to have 4500 kWh?

Actually, we don’t have any money at all and can only build according to the Building Energy Act. Because the surcharge of, say, €20,000 for KfW55 now has to be paid by ourselves without subsidies and would easily finance photovoltaics for the heat pump. Thanks to photovoltaics, the additional consumption is no longer a problem ;)