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?
W
WilderSueden26 Sep 2022 23:01Let’s assume someone really wants to choose the cheapest possible heating system and accepts that 1 kWh of electricity will only produce 1 kWh of heat. Wouldn’t it then be more logical to buy 5 fan heaters at the hardware store (assuming they are available at the moment 😉 ) instead of one panel heater for the window?
V
Vestaxx GmbH27 Sep 2022 09:37Now you’ve got it! That is certainly one option—just like, for example, 40 by 100 W incandescent bulbs. They might cost about 40 € total to buy. So why should a building family spend 10,000 times that amount on a heat pump system?
The option mentioned above is simply not comfortable. Our system has been measured by TU Berlin in comfort class A—that is, in the highest category. Just like a heat pump with underfloor heating.
The option mentioned above is simply not comfortable. Our system has been measured by TU Berlin in comfort class A—that is, in the highest category. Just like a heat pump with underfloor heating.
V
Vestaxx GmbH27 Sep 2022 09:39... and for the specified nearly zero-energy building with 150 m² (1,615 ft²) you only need 2 fan heaters -> heating load of the building -> approximately 4,000 watts.
R
RotorMotor27 Sep 2022 11:15To summarize again: We agree that a photovoltaic system makes sense, so I can consider and install it completely independently from the heating system. The financing of the photovoltaic system can also be handled entirely separately, and I don’t need to balance it against the heating system, insulation measures, or vehicles.
Therefore, we should set this aside now and only compare heating systems with each other.
1. I never said that one must be financed and the other not, but that I can finance both completely independently.
2. Where did I not answer one of your questions?
You mentioned a 30k air-to-water heat pump. For the air-to-water heat pump, I had once estimated €5,000, which might actually be too low.
Ours has a U-value of 0.15.
Unfortunately, there are very few numbers and facts available on the website, so I’m using this opportunity to ask a few questions:
1. What are the U-values?
2. What is the light transmission rate?
3. How is solar heat allowed into the house?
4. How was the efficiency determined?
Therefore, we should set this aside now and only compare heating systems with each other.
Vestaxx GmbH schrieb:
why he has to finance the photovoltaic system costs but not the same costs for the heat pump, you will have to explain to us here. But you do not respond to questions - unfortunately.
1. I never said that one must be financed and the other not, but that I can finance both completely independently.
2. Where did I not answer one of your questions?
Vestaxx GmbH schrieb:
How do you come up with an additional cost of €25,000?
You mentioned a 30k air-to-water heat pump. For the air-to-water heat pump, I had once estimated €5,000, which might actually be too low.
Vestaxx GmbH schrieb:
This is directly comparable to windows via the U-value.
Ours has a U-value of 0.15.
Vestaxx GmbH schrieb:
It is actually not worth it, but I am open to any reasonable arguments supported by verifiable data.
Unfortunately, there are very few numbers and facts available on the website, so I’m using this opportunity to ask a few questions:
1. What are the U-values?
2. What is the light transmission rate?
3. How is solar heat allowed into the house?
4. How was the efficiency determined?
V
Vestaxx GmbH27 Sep 2022 12:07Hello RotorMotor,
We have now found a good basis for discussion, and I’m happy to answer all your questions (I’m using the informal “you” as it’s common in forums; if you prefer otherwise, just let me know – no problem).
1. Comparing only heating systems is misleading because heat pumps naturally have a COP higher than that of infrared heating systems. The comparison is quickly settled in favor of heat pumps, which is widely accepted.
I also agree that if budget is no issue for the building family and they want to supply themselves almost independently, a system with a ground source heat pump plus a large photovoltaic system and a big battery is a great solution – but also very expensive. Hence the full cost calculation (by the way, calculated according to VDI 2067. The VDI 2067 guideline series deals with the cost-effectiveness calculation of building technology systems and applies to all building types). We assume the same budget and compare what the building family actually gets out of it. We present the most economically efficient system for the building family according to our calculations – and that turns out to be an electric direct heating system combined with photovoltaics and a battery. Ideally, this is the task of energy consultants, who are paid by customers to present the best, most economical, or at least different systems. However, often a heat pump is simply taken and that’s it. I want to give energy consultants the benefit of the doubt that they often don’t know better.
2. Financing is usually credit-based anyway – whether it’s heat pumps or electric direct heating with photovoltaics and battery. So both conditions are again the same.
3. A domestic hot water heat pump from LG costs about €2,000 including delivery to the curbside. Plug it into the socket, connect two water pipes beforehand, and you’re done. Anyone charging more than €5,000 for this is overcharging the customer – unfortunately this is quite common at the moment. 😡
4. U-value
The U-value of your floor is 0.15 W/m²K. The U-value of our heating glass is 0.5 W/m²K.
Let’s calculate the losses for both components:
150 m² x 0.15 W/m²K x 12 K (temperature difference between room temperature and ground – we neglect the higher heat transfer to the ground here) → 270 W loss to the ground.
Now for the glass:
20 m² (approx. 13% of the living area) x 0.5 W/m²K x 16 K (temperature difference between room temperature and outdoor air – we also neglect the lower heat transfer to the air) → 160 W loss to outdoor air.
So indeed, more energy is lost to the ground than through the glass. Was that what you expected?
5. Facts and figures
On our website, you’ll find the technical datasheet for the heating glass with important glass technical data:
U-value: typically 0.5 W/m²K
Light transmission: mathematically slightly lower – visually imperceptible
g-value: on the same level as standard triple insulating glass
Efficiency: This was measured in a test room at the Hermann-Rietschel-Institute at TU Berlin.
By the way, measured with two different methods. The first measurement showed 92%, and recently, through an external study commissioned by ISFH Hameln in cooperation with Forschungszentrum Jülich, with an improved measurement method, an efficiency of 95% was achieved.
I hope I have answered your questions satisfactorily so far and look forward to any further questions.
One more note – if you want to invest 90 minutes, have a look at the webinar on our website.
It includes 45 minutes of presentation and 45 minutes of questions from energy consultants.
Best regards,
Andreas
We have now found a good basis for discussion, and I’m happy to answer all your questions (I’m using the informal “you” as it’s common in forums; if you prefer otherwise, just let me know – no problem).
1. Comparing only heating systems is misleading because heat pumps naturally have a COP higher than that of infrared heating systems. The comparison is quickly settled in favor of heat pumps, which is widely accepted.
I also agree that if budget is no issue for the building family and they want to supply themselves almost independently, a system with a ground source heat pump plus a large photovoltaic system and a big battery is a great solution – but also very expensive. Hence the full cost calculation (by the way, calculated according to VDI 2067. The VDI 2067 guideline series deals with the cost-effectiveness calculation of building technology systems and applies to all building types). We assume the same budget and compare what the building family actually gets out of it. We present the most economically efficient system for the building family according to our calculations – and that turns out to be an electric direct heating system combined with photovoltaics and a battery. Ideally, this is the task of energy consultants, who are paid by customers to present the best, most economical, or at least different systems. However, often a heat pump is simply taken and that’s it. I want to give energy consultants the benefit of the doubt that they often don’t know better.
2. Financing is usually credit-based anyway – whether it’s heat pumps or electric direct heating with photovoltaics and battery. So both conditions are again the same.
3. A domestic hot water heat pump from LG costs about €2,000 including delivery to the curbside. Plug it into the socket, connect two water pipes beforehand, and you’re done. Anyone charging more than €5,000 for this is overcharging the customer – unfortunately this is quite common at the moment. 😡
4. U-value
The U-value of your floor is 0.15 W/m²K. The U-value of our heating glass is 0.5 W/m²K.
Let’s calculate the losses for both components:
150 m² x 0.15 W/m²K x 12 K (temperature difference between room temperature and ground – we neglect the higher heat transfer to the ground here) → 270 W loss to the ground.
Now for the glass:
20 m² (approx. 13% of the living area) x 0.5 W/m²K x 16 K (temperature difference between room temperature and outdoor air – we also neglect the lower heat transfer to the air) → 160 W loss to outdoor air.
So indeed, more energy is lost to the ground than through the glass. Was that what you expected?
5. Facts and figures
On our website, you’ll find the technical datasheet for the heating glass with important glass technical data:
U-value: typically 0.5 W/m²K
Light transmission: mathematically slightly lower – visually imperceptible
g-value: on the same level as standard triple insulating glass
Efficiency: This was measured in a test room at the Hermann-Rietschel-Institute at TU Berlin.
By the way, measured with two different methods. The first measurement showed 92%, and recently, through an external study commissioned by ISFH Hameln in cooperation with Forschungszentrum Jülich, with an improved measurement method, an efficiency of 95% was achieved.
I hope I have answered your questions satisfactorily so far and look forward to any further questions.
One more note – if you want to invest 90 minutes, have a look at the webinar on our website.
It includes 45 minutes of presentation and 45 minutes of questions from energy consultants.
Best regards,
Andreas
C
Christian 652 Oct 2022 18:37Actually, the facts are quite clear:
1. An electric direct heating system cannot have lower energy consumption than a heat pump, which uses a second input source: free outside air. And this with a factor of about 3.
2. The total installation costs of the underfloor heating can be lower than those of another heat generation system.
One should just not advertise the possibility of saving heating costs, because this is definitely not possible compared to a heat pump.
Any potential savings in maintenance costs and primary costs must then be calculated.
And there is really no reason to be afraid of underfloor heating systems.
1. An electric direct heating system cannot have lower energy consumption than a heat pump, which uses a second input source: free outside air. And this with a factor of about 3.
2. The total installation costs of the underfloor heating can be lower than those of another heat generation system.
One should just not advertise the possibility of saving heating costs, because this is definitely not possible compared to a heat pump.
Any potential savings in maintenance costs and primary costs must then be calculated.
And there is really no reason to be afraid of underfloor heating systems.
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