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?
C
chand19869 Oct 2022 21:34@OWLer
I appreciate your precision, but as a scientist, I tend to favor Occam’s razor: to look for the simplest solution to a problem (in a figurative sense).
@Vestaxx GmbH says that for the price of just a heat pump, you can roughly get their system plus photovoltaic panels. So that’s the comparison he makes.
The correct approach would be to compare their system with photovoltaic panels against a heat pump with photovoltaic panels and to include the additional interest costs of the higher investment. You also have to consider the system lifespans and replacement costs after a certain period.
There aren’t actually that many numbers involved.
I would also present them as running text, as long as it doesn’t turn into a wall of text.
I appreciate your precision, but as a scientist, I tend to favor Occam’s razor: to look for the simplest solution to a problem (in a figurative sense).
@Vestaxx GmbH says that for the price of just a heat pump, you can roughly get their system plus photovoltaic panels. So that’s the comparison he makes.
The correct approach would be to compare their system with photovoltaic panels against a heat pump with photovoltaic panels and to include the additional interest costs of the higher investment. You also have to consider the system lifespans and replacement costs after a certain period.
There aren’t actually that many numbers involved.
I would also present them as running text, as long as it doesn’t turn into a wall of text.
R
RotorMotor9 Oct 2022 22:15chand1986 schrieb:
The correct approach now would be to compare his system with photovoltaics against a heat pump system with photovoltaics, including the additional interest costs for the higher investment.
Also consider the lifespan of the systems and replacement costs after a certain period.
There aren’t that many numbers here.
I would also present them as running text, as long as it doesn’t turn into a wall of text. Here is the calculation from the previous example again, including interest.
Of course, as already mentioned, the increase in electricity prices must also be taken into account!
Let’s calculate everything over 18 years, since the managing director always requests VDI 2067, which specifies this as the “lifespan” for heat pumps:
150m² (1,615ft²) with 40kWh/m²a (13,000kWh/ft²/year) → 6000kWh/year heating energy demand
10kWp photovoltaic + 5kWh storage → approximately 15kWh/day in Nov, Dec, Jan, Feb. With 10kWh/day for household electricity including hot water, 5kWh/day remain for heating.
Hot water is left out here because both systems can provide it at a COP of 4, so it makes no difference; the electricity for hot water is included in the household electricity.
Electricity purchase price: 35¢/kWh
Feed-in tariff: 8.2¢/kWh
Interest rate: 3.5% (current fixed rate for 10 years)
Electricity price increase: 6% (average of the last 20 years)
Vestaxx:
Additional cost compared to standard windows: €10,000
Purchase and installation of hot water heat pump: €5,000
Interest on the investment over 18 years: €5,239
4 months * 30 days * 5kWh/day = 600kWh from photovoltaic electricity
Remaining 5,400kWh purchased from the grid
Total (on average, due to rising electricity prices): 5400 * (0.35 + 0.35 * 1.06^18) / 2 + 600 * 0.082 = €3,691/year
After 18 years, this amounts to: €86,686
Heat pump:
Hydraulics: €80/m² * 150m² = €12,000
Purchase and installation of air-to-water monoblock heat pump: €20,000
Interest on the investment over 18 years: €11,176
Electricity demand: 6000 / 4 = 1,500kWh
Remaining electricity purchased: 900kWh
Total (on average, due to rising electricity prices): 900 * (0.35 + 0.35 * 1.06^18) / 2 + 600 * 0.082 = €656/year
After 18 years, this amounts to: €54,988
This results in additional costs for Vestaxx of €31,697 compared to the heat pump in this example.
C
chand198610 Oct 2022 04:02RotorMotor schrieb:
Here is the calculation from the previous example again, now including interest.
Of course, as mentioned before, the increase in electricity prices must also be taken into account!
Let's calculate over 18 years, because the managing director always wants to follow VDI 2067, which states this as the lifespan of a heat pump:
150m² (1,615 sq ft) with 40kWh/m²a (40kWh/sq m per year) → 6000kWh/year heating energy demand
10kWp photovoltaic system + 5kWh battery storage → ~15kWh/day in Nov, Dec, Jan, Feb. With 10kWh for household electricity including hot water, 5kWh/day remain for heating.
I leave out hot water since both systems provide it with a COP of 4, so it makes no difference; electricity for hot water is included in household electricity.
Electricity purchase price 35¢/kWh
Feed-in tariff: 8.2¢/kWh
Interest rate 3.5% (current 10-year fixed rate)
Electricity price increase 6% (average of the last 20 years)
Vestaxx:
Additional cost compared to regular windows: €10,000
Purchase and installation of BWWP: €5,000
Interest on purchase over 18 years: €5,239
4 months * 30 days * 5 kWh/day = 600 kWh from photovoltaic electricity
Remaining 5400 kWh purchased
Totals (average, due to increasing electricity prices): 5400*(0.35+0.35*1.06^18)/2 + 600*0.082 = €3,691/year
After 18 years this totals: €86,686
Heat pump:
Hydraulic system: €80/m² * 150m² = €12,000
Purchase of air-to-water monoblock heat pump and installation: €20,000
Interest on purchase over 18 years: €11,176
Electricity demand: 6000/4 = 1500 kWh
Remaining purchase 900 kWh
Totals (average, due to increasing electricity prices): 900*(0.35+0.35*1.06^18)/2 + 600*0.082 = €656/year
After 18 years this totals: €54,988
This results in additional costs for Vestaxx of €31,697 compared to the heat pump in this example. Something like that.
Now I will play devil’s advocate and say: The heat pump calculation is missing maintenance/repairs plus replacement. @Vestaxx GmbH assumes that in the period considered above the heat pump will reach the end of its service life and need to be replaced, whereas the heated windows are maintenance-free and last until the next window replacement is due anyway.
If roughly €30,000 accumulate over 18 years, during which normal inflation continues, does that balance out?
(I assume this is the point the famous business administration texts are making?)
chand1986 schrieb:
Something like that.
Now, playing devil’s advocate, I’d say: Maintenance/repair plus replacement costs are missing for the heat pump. @Vestaxx GmbH assumes that within the above-mentioned time frame, the heat pump will reach the end of its lifespan and will need to be replaced, while the heated windows are maintenance-free and will last until you want to replace the windows anyway.
But then please also include maintenance, repair, and replacement for the domestic hot water heat pump required for the heated windows ;-)
C
chand198610 Oct 2022 07:17filosof schrieb:
But please also include the maintenance, repair, and replacement costs of the potable water heat pump required for the window heating system ;-) Correct!
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