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?
V
Valentin-S8 Dec 2021 19:35EinHausfür5 schrieb:
But if you have already gained new insights in the meantime, I would be happy if you share them with us.One insight I have been able to determine so far is that the panel heating should cover 20% of the area to be heated. In other words, 20% of the room’s floor area.
C
Carsten_all-Da9 Jan 2022 07:42Hello EinHausfür5,
I heat my house exclusively with a water-based wood stove (17 kW). My house was built in 1951 and was completely renovated about 10 years ago, upgraded with thermal insulation to passive house standards. Unfortunately, the wood stove is not quite sufficient for both domestic hot water and space heating. That means the house is comfortably heated to 20°C (68°F) in winter at an outside temperature of -5°C (23°F). However, I have two people who feel cold at this standard.
I am currently finishing the loft for one of my children, or rather completing it, because the walls (sloped) are already done. What is missing here is the heating system. That is the main problem. For a water-based system, there are no vertical walls. For an electric underfloor heating system, the required air gap is missing after raising the floor (adding another 2 cm (1 inch) would reduce headroom too much).
During construction, I placed a 0.8 m² (8.6 ft²) panel infrared heater in the room, and as expected, the temperature increased significantly to 19°C (66°F). This is sufficient for working.
I have also heard about the Vestaxx system, and the claim sounds plausible that doubling the heated surface area would raise the room temperature well above 19°C (66°F). The question remains about cost efficiency. This brings me to the general recommendation to equip every house roof with photovoltaic panels. I have such a system on my roof. With about 8.5 kW capacity, heating with electricity is quite manageable. Without a photovoltaic system, one should talk to their energy provider to find out if there is a cheaper tariff available for electric heating. Many households used to have storage heaters. The bad reputation of these heaters was only due to their poor efficiency. Storage heaters cannot be compared with heated glass surfaces, as the method of heat generation is completely different. Most heat loss still occurs through windows rather than exterior walls today. A major advantage of heated window glass is that the temperature near the windows does not drop but stays the same as the interior walls. This also eliminates the usual uncomfortable drafts caused by temperature differences near the windows. Anyone considering a more comfortable living environment will benefit from this system. For domestic hot water, there are also common systems available. There is no need to install a heating system costing tens of thousands of dollars.
I will replace my roof windows with these “converted” heated glass panes and report on the effect afterward.
I wish you a good, healthy, and comfortable new year.
I heat my house exclusively with a water-based wood stove (17 kW). My house was built in 1951 and was completely renovated about 10 years ago, upgraded with thermal insulation to passive house standards. Unfortunately, the wood stove is not quite sufficient for both domestic hot water and space heating. That means the house is comfortably heated to 20°C (68°F) in winter at an outside temperature of -5°C (23°F). However, I have two people who feel cold at this standard.
I am currently finishing the loft for one of my children, or rather completing it, because the walls (sloped) are already done. What is missing here is the heating system. That is the main problem. For a water-based system, there are no vertical walls. For an electric underfloor heating system, the required air gap is missing after raising the floor (adding another 2 cm (1 inch) would reduce headroom too much).
During construction, I placed a 0.8 m² (8.6 ft²) panel infrared heater in the room, and as expected, the temperature increased significantly to 19°C (66°F). This is sufficient for working.
I have also heard about the Vestaxx system, and the claim sounds plausible that doubling the heated surface area would raise the room temperature well above 19°C (66°F). The question remains about cost efficiency. This brings me to the general recommendation to equip every house roof with photovoltaic panels. I have such a system on my roof. With about 8.5 kW capacity, heating with electricity is quite manageable. Without a photovoltaic system, one should talk to their energy provider to find out if there is a cheaper tariff available for electric heating. Many households used to have storage heaters. The bad reputation of these heaters was only due to their poor efficiency. Storage heaters cannot be compared with heated glass surfaces, as the method of heat generation is completely different. Most heat loss still occurs through windows rather than exterior walls today. A major advantage of heated window glass is that the temperature near the windows does not drop but stays the same as the interior walls. This also eliminates the usual uncomfortable drafts caused by temperature differences near the windows. Anyone considering a more comfortable living environment will benefit from this system. For domestic hot water, there are also common systems available. There is no need to install a heating system costing tens of thousands of dollars.
I will replace my roof windows with these “converted” heated glass panes and report on the effect afterward.
I wish you a good, healthy, and comfortable new year.
Carsten_all-Da schrieb:
hydraulically connected fireplace stove (17 kW). My house was built in 1951 and was completely renovated almost 10 years ago, upgraded with thermal insulation to passive house standards. Unfortunately, the fireplace stove is not sufficient for domestic hot water and space heating. That means: the house is heated to 20°C (68°F) in winter when the outside temperature is -5°C (23°F).Can you find the mistake(s)?Where are the 17 kW going if the house isn’t warming up?
Passive house standard? 🙄
No hot water?
I assume typical mayflies. With "questionable" products, like this window heater as well as in the parallel thread about HPL Picea.
Then the myth of being able to significantly support an electric heater directly with photovoltaic power in winter. In any case, I had less than 100 kWh (107.6 kWh) yield in December.
Then the myth of being able to significantly support an electric heater directly with photovoltaic power in winter. In any case, I had less than 100 kWh (107.6 kWh) yield in December.
B
Benutzer2009 Jan 2022 16:32OWLer schrieb:
In December, I had a yield of less than 100 kWh. And only between 9 a.m. and 4 p.m. at most. During the rest of the time (e.g., cold nights), you have to buy expensive electricity.
V
Vestaxx GmbH26 Sep 2022 15:13Hello everyone,
this is Andreas, Managing Director of the manufacturer Vestaxx GmbH, writing personally.
Unfortunately, I only became aware today of the questions, concerns, and comments in this very interesting forum.
As the system provider of the window heating, I would like to clarify a few points.
First of all: Of course, we are interested in the sale of our systems and therefore also appreciate positive feedback in this forum, but we are happy to accept any constructive criticism and answer all questions about our heating system. If we don’t convince you, we advise: please do not buy our system!
I cannot answer all the raised questions here—that would go beyond the scope—so I refer you to a webinar held a few months ago for energy consultants of the GIH, which can be found on our website.
Basically, I would like to consider the following:
According to current statistics, about every second newly built house is equipped with a heat pump. The cost for that is currently around 40,000 € (approximately $44,000) for an air-to-water heat pump. For the same money, a building family can get a window heating system (only the additional cost for the heating function) including installation. In a single-family home, the price is around +/- 10,000 € (about $11,000). So the building family saves around 30,000 € (about $33,000). With this, they can purchase a hot water heat pump as well as a very large photovoltaic system including battery storage.
Example calculation of heating energy demand, domestic hot water production, and household electricity consumption (total annual energy requirement of the house):
Basis: 150 m² (1,615 sq ft) living space / 4-person household / KfW40 building standard
Specific heating energy demand = about 30 kWh/m² per year, so 4,500 kWh + about 12.5 kWh/m² for hot water demand equals 1,875 kWh (let’s estimate 2,000 kWh).
Additionally—and this is often forgotten—there is the household electricity consumption -> 4,000 kWh/year.
Altogether, approximately 10,500 kWh annual energy demand.
What are the costs to cover this energy demand?
Heat pump system -> heating energy demand 4,500 kWh / seasonal performance factor (SPF) of 3 -> 1,500 kWh per year
(I know many will now argue for an SPF of 4. To those I would recommend not relying on brochure figures, but on independent studies by recognized institutes. There, an average SPF of 2.6 is given for air-to-water heat pumps.)
In addition, the utilization factor of 70% applies (source: TU Berlin - Hermann-Rietschel-Institut), which lands us below 2!
But since I don’t want to rely on 2 here, we use 3. (Note: I could also assume 1,000, but more on that later ;o))
So:
Hot water demand -> from 2,000 kWh results in roughly 750 kWh (SPF = 3)
Plus household electricity -> 4,000 kWh
Altogether, the household with an air-to-water heat pump system needs to purchase 6,250 kWh of electricity.
Assuming a current electricity price of 0.35 €/kWh, that amounts to approximately 2,200 € (about $2,400) annually.
Now let's see what happens with a direct electric heating system (heating glass panels + hot water heat pump + 15 kWp photovoltaic system including battery storage).
Heating energy demand = 4,500 kWh
Hot water demand = 750 kWh (hot water heat pump with SPF = 3)
Household electricity = 4,000 kWh
Total = 9,250 kWh
Ah—some may say now. That’s 3,000 kWh more than with the heat pump! Didn’t I say so!!!
True, but what does the photovoltaic system do?
A 15 kWp photovoltaic system affordable for the saved money, even with a less-than-ideal orientation and location, still produces about 900 kWh per kWp annually. That means the system generates approximately 13,500 kWh (CO2-free) electricity per year -> about two-thirds in the summer half-year and one-third in the winter half-year.
Let’s look at the annual balance: The house produces more energy than it consumes over the year -> this is called a plus-energy house!
In the above constellation, at least half (in fact, more) of the generated electricity is used directly in the house—about 6,500 kWh.
This does not need to be purchased. The remaining 6,500 kWh is fed into the grid and compensated at about 0.08 €/kWh. That equals approximately 500 € ($550) annually.
Now let’s look again at the energy costs of the direct electric heating system:
9,250 kWh minus 6,500 kWh equals only 2,750 kWh, which largely consists of externally purchased winter heating electricity.
2,750 kWh at 0.35 €/kWh equals about 1,000 € (approximately $1,100), so roughly 1,200 € (about $1,300) less annually than with the heat pump system!
And that’s not all, because if you have been paying attention, you will have noticed that we haven’t yet deducted the photovoltaic compensation of 500 €.
That would make the total annual energy cost for the direct electric heating house just 500 € (around $550).
THAT’S WHY we do this! Our existing customers appreciate it. Feel free to recalculate the above example with a seasonal performance factor of 5. It doesn’t help much!
I will stop here now, because this has become quite long.
But anyone planning to build a single-family house should take the time to think this through.
Please feel free to recalculate for your own case and ask your questions openly here or provide criticism.
I will respond promptly.
Best regards – Andreas
this is Andreas, Managing Director of the manufacturer Vestaxx GmbH, writing personally.
Unfortunately, I only became aware today of the questions, concerns, and comments in this very interesting forum.
As the system provider of the window heating, I would like to clarify a few points.
First of all: Of course, we are interested in the sale of our systems and therefore also appreciate positive feedback in this forum, but we are happy to accept any constructive criticism and answer all questions about our heating system. If we don’t convince you, we advise: please do not buy our system!
I cannot answer all the raised questions here—that would go beyond the scope—so I refer you to a webinar held a few months ago for energy consultants of the GIH, which can be found on our website.
Basically, I would like to consider the following:
According to current statistics, about every second newly built house is equipped with a heat pump. The cost for that is currently around 40,000 € (approximately $44,000) for an air-to-water heat pump. For the same money, a building family can get a window heating system (only the additional cost for the heating function) including installation. In a single-family home, the price is around +/- 10,000 € (about $11,000). So the building family saves around 30,000 € (about $33,000). With this, they can purchase a hot water heat pump as well as a very large photovoltaic system including battery storage.
Example calculation of heating energy demand, domestic hot water production, and household electricity consumption (total annual energy requirement of the house):
Basis: 150 m² (1,615 sq ft) living space / 4-person household / KfW40 building standard
Specific heating energy demand = about 30 kWh/m² per year, so 4,500 kWh + about 12.5 kWh/m² for hot water demand equals 1,875 kWh (let’s estimate 2,000 kWh).
Additionally—and this is often forgotten—there is the household electricity consumption -> 4,000 kWh/year.
Altogether, approximately 10,500 kWh annual energy demand.
What are the costs to cover this energy demand?
Heat pump system -> heating energy demand 4,500 kWh / seasonal performance factor (SPF) of 3 -> 1,500 kWh per year
(I know many will now argue for an SPF of 4. To those I would recommend not relying on brochure figures, but on independent studies by recognized institutes. There, an average SPF of 2.6 is given for air-to-water heat pumps.)
In addition, the utilization factor of 70% applies (source: TU Berlin - Hermann-Rietschel-Institut), which lands us below 2!
But since I don’t want to rely on 2 here, we use 3. (Note: I could also assume 1,000, but more on that later ;o))
So:
Hot water demand -> from 2,000 kWh results in roughly 750 kWh (SPF = 3)
Plus household electricity -> 4,000 kWh
Altogether, the household with an air-to-water heat pump system needs to purchase 6,250 kWh of electricity.
Assuming a current electricity price of 0.35 €/kWh, that amounts to approximately 2,200 € (about $2,400) annually.
Now let's see what happens with a direct electric heating system (heating glass panels + hot water heat pump + 15 kWp photovoltaic system including battery storage).
Heating energy demand = 4,500 kWh
Hot water demand = 750 kWh (hot water heat pump with SPF = 3)
Household electricity = 4,000 kWh
Total = 9,250 kWh
Ah—some may say now. That’s 3,000 kWh more than with the heat pump! Didn’t I say so!!!
True, but what does the photovoltaic system do?
A 15 kWp photovoltaic system affordable for the saved money, even with a less-than-ideal orientation and location, still produces about 900 kWh per kWp annually. That means the system generates approximately 13,500 kWh (CO2-free) electricity per year -> about two-thirds in the summer half-year and one-third in the winter half-year.
Let’s look at the annual balance: The house produces more energy than it consumes over the year -> this is called a plus-energy house!
In the above constellation, at least half (in fact, more) of the generated electricity is used directly in the house—about 6,500 kWh.
This does not need to be purchased. The remaining 6,500 kWh is fed into the grid and compensated at about 0.08 €/kWh. That equals approximately 500 € ($550) annually.
Now let’s look again at the energy costs of the direct electric heating system:
9,250 kWh minus 6,500 kWh equals only 2,750 kWh, which largely consists of externally purchased winter heating electricity.
2,750 kWh at 0.35 €/kWh equals about 1,000 € (approximately $1,100), so roughly 1,200 € (about $1,300) less annually than with the heat pump system!
And that’s not all, because if you have been paying attention, you will have noticed that we haven’t yet deducted the photovoltaic compensation of 500 €.
That would make the total annual energy cost for the direct electric heating house just 500 € (around $550).
THAT’S WHY we do this! Our existing customers appreciate it. Feel free to recalculate the above example with a seasonal performance factor of 5. It doesn’t help much!
I will stop here now, because this has become quite long.
But anyone planning to build a single-family house should take the time to think this through.
Please feel free to recalculate for your own case and ask your questions openly here or provide criticism.
I will respond promptly.
Best regards – Andreas
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