Hello everyone,
My husband and I attended a home exhibition today featuring a local timber house builder (Schleswig-Holstein) and there we learned about the Vestaxx window heating system.
Is there anyone here who has experience with the Vestaxx window heating?
At first, it sounds unusual to have the heating integrated into the windows. For the triple-glazed windows, a nanotechnology-based, invisible layer is applied to the inner surface of the innermost pane, which warms the glass up to 40 degrees Celsius (104°F) via infrared and heats the room. The warmth actually felt very comfortable, and the windows were completely cold on the outside (today’s temperature was below 10 degrees Celsius (50°F)). Allegedly, the Vestaxx window heating transfers 92% of its heat to the room, and the Technical University of Berlin has tested this Vestaxx window heating system and rated it positively. It appears to have been on the market only recently.
Overall, I find this quite interesting. It is significantly cheaper than other heating systems, allows individual control of each room, and unlike underfloor heating, it is very responsive.
Of course, this only makes sense in a low-energy house (the timber builder mainly constructs 40+ standard homes), as the system runs on electricity. In that case, the Vestaxx window heating is said to consume very little power.
This is my impression from the expo; of course, they want to sell the system.
What are your experiences with Vestaxx? Have you heard of this system before? Could it be an alternative to conventional heating? Does it have a future?
My husband and I attended a home exhibition today featuring a local timber house builder (Schleswig-Holstein) and there we learned about the Vestaxx window heating system.
Is there anyone here who has experience with the Vestaxx window heating?
At first, it sounds unusual to have the heating integrated into the windows. For the triple-glazed windows, a nanotechnology-based, invisible layer is applied to the inner surface of the innermost pane, which warms the glass up to 40 degrees Celsius (104°F) via infrared and heats the room. The warmth actually felt very comfortable, and the windows were completely cold on the outside (today’s temperature was below 10 degrees Celsius (50°F)). Allegedly, the Vestaxx window heating transfers 92% of its heat to the room, and the Technical University of Berlin has tested this Vestaxx window heating system and rated it positively. It appears to have been on the market only recently.
Overall, I find this quite interesting. It is significantly cheaper than other heating systems, allows individual control of each room, and unlike underfloor heating, it is very responsive.
Of course, this only makes sense in a low-energy house (the timber builder mainly constructs 40+ standard homes), as the system runs on electricity. In that case, the Vestaxx window heating is said to consume very little power.
This is my impression from the expo; of course, they want to sell the system.
What are your experiences with Vestaxx? Have you heard of this system before? Could it be an alternative to conventional heating? Does it have a future?
Vestaxx GmbH schrieb:
I am comparing two systems that have exactly the same costs and looking at the outcome.
And that is financially quite inaccurate. Yes, because you are not actually comparing two systems with the same costs, but two systems with costs a + b versus one system with cost c. By chance, the total investment of a + b equals c today. But a and b are two different investments. You would need to conduct a separate cost-effectiveness analysis for each.
Because – here’s the key point – photovoltaic systems currently always have a positive cost-effectiveness, they can always be financed through third parties. The photovoltaic system pays for itself. So you can install it independently of the heating system.
Vestaxx GmbH schrieb:
Why does the system have to produce electricity on the outer glass surface to be financially accurate (which in turn is completely uneconomical)? Because only then would it be a SINGLE investment and could be evaluated in a SINGLE cost-effectiveness calculation.
With your calculation, you could just as well say that someone uses the saved investment costs for the technology to buy a bond package from your company and generate a profit. Do you perhaps understand it now?
R
RotorMotor10 Oct 2022 17:25Vestaxx GmbH schrieb:
And yes – of course there are loans (they are currently very attractive again), but they still have to be repaid.
Loan amount + interest -> every bank is happy, and the building family will eventually have to move out if they can no longer meet the loan payments. So you would voluntarily prefer to pay X € to an energy provider rather than to a bank, so that afterward you own a more efficient heating system?
Vestaxx GmbH schrieb:
So showing your arguments to the energy consultants and professionals – ... what would it achieve for me? Yes, you could learn a lot from it.
And as a result, you could advise your clients fairly.
But sure, the financial benefit for you personally might suffer.
Vestaxx GmbH schrieb:
I’m slowly reaching a point where I’m wondering whether I should keep struggling with people who have dangerous half-knowledge. So far, those people have shown more detailed expertise and more complete calculations than you.
I do believe it’s frustrating, though.
Vestaxx GmbH schrieb:
Because for genuinely interested people it must be a nightmare to read posts like these … At least for those who have already purchased?
Vestaxx GmbH schrieb:
… from anonymous people. What’s the problem with that? Allow open and honest discussion.
Many posts come from forum members who have been active here for years, contributed hundreds of posts, and helped each other with house planning and heating systems.
There are also many calculations and figures that anyone can check.
Vestaxx GmbH schrieb:
My interests are open and known because I am not anonymous. Yes, thanks, that definitely makes it easier to put the “posts” into perspective.
V
Vestaxx GmbH10 Oct 2022 18:24OWLer schrieb:
Finally, it’s moving forward here. Fortunately for you, I’m not allowed to go outside for at least the next 5 days, so I’m on call for more calculations and discussions.
Oh, what happened there? Has our house shrunk? We started from 4500 kWh (4500 kWh), didn’t we?
Then also factor in the domestic hot water heat pump. The €200 seems about right, but most homeowners probably won’t maintain it after the warranty period. The heat pump signals errors, and maintenance basically means checking the unit and nodding approvingly. Maybe the annual performance factor is read off as well.
Sometimes I get the feeling you don’t have a photovoltaic system that’s supposed to make you independent in winter. With my 9.5 kWp (kilowatt peak), I don’t get even 100 kWh (100 kWh) per month from November to January. Nothing comes from solar in winter, so you have to purchase electricity to operate. My “plus-energy house” with 6-8 cents per kWh in summer doesn’t help with that! That’s exactly why there’s all the political discussion about dark doldrums.
Just admit you don’t understand greenhouse gas emissions and their accounting according to the GHG Protocol.
Sorry, but that’s the worldwide (industry) standard for assessing sustainability. That doesn’t change my rating of glass heating as a major environmental offender. It’s really time for your master’s thesis, because doing the calculations yourself is quite enlightening — and unfortunately disastrous in your case.
And it doesn’t help that you can hold your coating elements in your hand. Heating usage unfortunately pulls our model home’s CO2 footprint down by at least 16–20 tons (16–20 T) of CO2 over time. Meanwhile, the heat pump owner can happily fly to New York a few times just for a hot dog.
A fundamental question: how was the 92/95% efficiency determined? That’s the efficiency of the heated glass, right? What I don’t understand is how the heating power is regulated from the 230 V (230 V) mains voltage. Doesn't that require a transformer or similar?
Then just take the 4500 kWh (4500 kWh) — you still won’t get good calculations. Moreover, modern construction, especially new builds, are heading towards passive house standards, where we’re talking about 15 kWh/m² (15 kWh/m²), so for your example that’s 2,250 kWh (2,250 kWh), and two-thirds of that is 1,500 kWh (1,500 kWh).
Regarding domestic hot water heat pump maintenance costs – it’s basically a better refrigerator. Do you maintain your refrigerator? So in your calculation, add another 20 × €200 = €4,000.
The heat pump signals errors — and then it gets expensive ;o)
Nothing comes in winter — I have a photovoltaic system and don’t know what’s going on with yours. Just look up monthly data (you have time) from recognized institutes or from photovoltaics monitoring. The current price is €0.086 per kWh (8.6 c/kWh) and rising! And solar does help — I already calculated that. Do check it out.
Regarding your claim that I have no idea about greenhouse gases because I criticize your Denglish writing, that is completely baseless and frankly embarrassing. You think you’re so smart — it’s sickening — and your assessment is just completely wrong.
Say something about hand versus forklift — but again, nothing. Better to just act smart without substance.
Now, regarding your factual comment (I probably won’t reply to that nonsense at the start anymore): 95% is the heat output to the interior and 5% the losses to the outside, measured by the Hermann-Rietschel-Institute at TU Berlin in a test chamber. We don’t need transformers — we usually work directly with 230 V. You can look up the rest yourself — you do have time.
I don’t have as much time as you (I prefer to take care of my clients), so I will only briefly respond to your nonsense — but happy to answer specific questions.
@Vestaxx GmbH
Why are you comparing systems that are not comparable? If you clearly have an issue with heating pipes embedded in the screed (either because of the costs or due to the use of water), the proper comparison to your window heating system is a classic air-to-air heat pump. This technology has been proven for ages, especially in prefabricated houses when it comes to reducing heating costs.
Please run a comparison using that system—I would really be interested in the results! Since the cost of an air-to-air heat pump is lower, you could then calculate both heating methods with or without photovoltaic systems to get a truly comparable outcome.
Why are you comparing systems that are not comparable? If you clearly have an issue with heating pipes embedded in the screed (either because of the costs or due to the use of water), the proper comparison to your window heating system is a classic air-to-air heat pump. This technology has been proven for ages, especially in prefabricated houses when it comes to reducing heating costs.
Please run a comparison using that system—I would really be interested in the results! Since the cost of an air-to-air heat pump is lower, you could then calculate both heating methods with or without photovoltaic systems to get a truly comparable outcome.
R
RotorMotor10 Oct 2022 18:42Vestaxx GmbH schrieb:
Regarding the maintenance costs of the BWWP – it’s a better refrigerator – do you maintain your refrigerator? So, add another 20 x 200€ = 4000 € to your calculation. That’s quite something. The gentleman doesn’t even realize that a BWWP and an air-to-water heat pump basically use the same technology.
An air-to-water heat pump is just as much a refrigerator as a BWWP is. The maintenance effort is therefore identical. The only possible argument could be that replacement parts for a full-scale air-to-water heat pump might be somewhat more expensive because they are sometimes larger and more powerful.
Vestaxx GmbH schrieb:
Nothing comes in winter – I have a photovoltaic system and don’t know what’s wrong with yours. Just google monthly data (you have time) from recognized institutes or photovoltaic sources. And the current price is 8.6 c/kWh (with an upward trend!) And that already helps – I calculated that. Just check it yourself. We have all checked multiple times already and supported it with figures and sources. The yield in winter is low. It is therefore not sufficient to power a heating system.
Vestaxx GmbH schrieb:
As for your comment that I have no understanding of greenhouse gases because I criticize your Denglisch writing style, that is completely unfounded and simply embarrassing. YOU think you’re so smart – it’s sickening – and YOUR assessment is just wrong. Instead of rambling, making claims, and insulting, a proper counterargument would be more appropriate.
This is starting to get borderline. Wow.
The much bigger leverage for cost-conscious builders is to forgo the Passive House standard. Building according to KfW 55 or the Building Energy Act and using an air-to-water heat pump or at most an air-to-air heat pump certainly offers a better price-to-performance ratio. Plus: both can provide cooling in summer.
In your case, large window areas are needed, which then require excellent shading during summer.
I have provided numbers. What CO2 equivalents did your calculation use? Will we ever see them? Professionally, I deal with life cycle assessment—oh sorry, probably called Lebenszykluserfassung or -analyse in German—in the context of sustainability projects.
I have clearly explained my calculation method—also including hand versus forklift, taking into account several hundred kilograms of material for the heat pump and underfloor heating pipes. And with that, you don’t exceed 1000 kg (2205 lbs) of CO2 emissions. Unfortunately, that is what your system emits additionally EVERY YEAR. So after 2 to 3 years at the latest, the CO2 footprint of the house installation has paid off compared to Vestaxx.
What mistake did I make in my calculation, aside from rounding errors or omitted valves amounting to about 20 kg (44 lbs) of material?
Unfortunately, the "argumentation" is becoming quite polemic and detached from the facts. The anonymous users here have presented numbers, interest rates, factors, assumptions, and transparency. The response is statements that can be perceived as insults.
Vestaxx GmbH schrieb:
Furthermore, modern and especially new construction methods are moving towards the Passive House standard, and we are talking about 15 kWh/m² (5 Btu/ft²)
The much bigger leverage for cost-conscious builders is to forgo the Passive House standard. Building according to KfW 55 or the Building Energy Act and using an air-to-water heat pump or at most an air-to-air heat pump certainly offers a better price-to-performance ratio. Plus: both can provide cooling in summer.
In your case, large window areas are needed, which then require excellent shading during summer.
Vestaxx GmbH schrieb:
Regarding your remark that I have no knowledge about greenhouse gases because I criticized your Denglish spelling, that is completely unfounded and just embarrassing. YOU think you’re so smart – it’s sickening – and YOUR assessment is simply wrong.
Say something about hand versus forklift – but again, nothing. Prefer to act smart instead.
I have provided numbers. What CO2 equivalents did your calculation use? Will we ever see them? Professionally, I deal with life cycle assessment—oh sorry, probably called Lebenszykluserfassung or -analyse in German—in the context of sustainability projects.
I have clearly explained my calculation method—also including hand versus forklift, taking into account several hundred kilograms of material for the heat pump and underfloor heating pipes. And with that, you don’t exceed 1000 kg (2205 lbs) of CO2 emissions. Unfortunately, that is what your system emits additionally EVERY YEAR. So after 2 to 3 years at the latest, the CO2 footprint of the house installation has paid off compared to Vestaxx.
What mistake did I make in my calculation, aside from rounding errors or omitted valves amounting to about 20 kg (44 lbs) of material?
Unfortunately, the "argumentation" is becoming quite polemic and detached from the facts. The anonymous users here have presented numbers, interest rates, factors, assumptions, and transparency. The response is statements that can be perceived as insults.
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