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
Vestaxx GmbH11 Oct 2022 12:19kati1337 schrieb:
Oh @RotorMotor, now you're coming at him again with those tricky numbers.
Don’t you realize you just didn’t understand it properly? You just need to watch the webinar, then everything will become clear! 😀 See, now Kati got it – I told you, the webinar is worth its weight in gold.
The energy consultants agree as well.
I
Interrupt11 Oct 2022 12:21RotorMotor schrieb:
5400*(35+35*1.06^18)/2+600*8.2=3,691€/yearSorry, I’m a bit late to the discussion and trying to understand the formula. I don’t (yet) have photovoltaic panels on my roof and I’m not very confident with the economic calculations.
@RotorMotor, why do you add 600 kWh of feed-in tariff that you previously counted as self-consumption in the electricity demand? A kilowatt-hour generated by the photovoltaic system can’t be both self-used and sold at the same time! Apart from that, shouldn’t the feed-in tariff be subtracted instead of added (since it’s income, not an expense)? I’m a bit confused here.
V
Vestaxx GmbH11 Oct 2022 12:23RotorMotor schrieb:
Not towards any target or just not towards your target?
I am still happy to assist if you have specific suggestions for changes (including explanations).
I scrolled through again and so far I could only find this:
Yes, the photovoltaic system was already included, as well as household electricity during the relevant period, but I will gladly highlight it again in red for you:
150m² (1600 ft²) with 40kWh/m²a (13000 BTU/ft²/year) -> 6000kWh/year heating energy demand
10kWp photovoltaic + 5kWh storage -> approximately 15kWh/day in Nov, Dec, Jan, Feb. With 10kWh for household electricity including hot water, 5kWh/day remain for heating
The costs of the photovoltaic system are not listed in this example because the system finances itself through feed-in tariffs and savings on household electricity.
I leave out hot water costs because both systems can provide it with a seasonal performance factor (SPF) of 4, so it makes no difference; the electricity for hot water is included in the household electricity calculation.
Electricity purchase price: 35¢/kWh
Feed-in tariff: 8.2¢/kWh
Interest rate: 3.5% (current rate for 10-year fixed term)
Electricity price increase: 6% (average over the last 20 years)
Vestaxx + Photovoltaic:
Additional cost compared to standard windows: €10,000
Purchase and installation of brine-water heat pump (BWWP): €5,000
Interest on purchase over 18 years: €5,239
Maintenance of BWWP: €200/year
4 [months] * 30 [days] * 5 [kWh/day] = 600 [kWh] from photovoltaic electricity
Remaining 5400 kWh as purchased electricity
Total (average, due to rising electricity prices) 5400 * (35 + 35 * 1.06^18)/2 + 600 * 8.2 = €3,691/year
After 18 years, that totals: €90,286
Heat pump + Photovoltaic:
Hydraulics: €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
Maintenance of air-to-water heat pump: €250/year
Electricity demand: 6000/4 = 1500 kWh
Remaining 900 kWh as purchased electricity
Total (average, due to rising electricity prices) 900 * (35 + 35 * 1.06^18)/2 + 600 * 8.2 = €656/year
After 18 years, that totals: €59,488
Vestaxx without Photovoltaic:
Additional cost compared to standard windows: €10,000
Purchase and installation of BWWP: €5,000
Interest on purchase over 18 years: €5,239
Maintenance of BWWP: €200/year
Total (average, due to rising electricity prices) 6000 * (35 + 35 * 1.06^18)/2 + 600 * 8.2 = €3,691/year
After 18 years, that totals: €94,558
Heat pump without Photovoltaic:
Hydraulics: €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
Maintenance of air-to-water heat pump: €250/year
Electricity demand: 6000 / 4 = 1500 kWh
Total (average, due to rising electricity prices) 1500 * (35 + 35 * 1.06^18)/2 = €1,011/year
After 18 years, that totals: €65,878
This results in additional costs for Vestaxx of €30,798 compared to the heat pump in this example.
So for 18 years, you pay €142 more per month without even having underfloor heating remaining at the end of the term!
All the money is gone to the energy provider and largely transformed into CO2.
The calculation is unfortunately completely wrong for the simple reason that it completely omits the total yield of the photovoltaic system for Vestaxx + photovoltaic and only takes the yield that can be directly used for heating in winter. Everything else the photovoltaic system produces is simply ignored.
V
Vestaxx GmbH11 Oct 2022 12:24Interrupt schrieb:
Sorry, I'm a bit late to the party and I'm trying to understand the formula. I currently don’t have any photovoltaic system on my roof and am not very good at the economic calculations.
@RotorMotor, why are you adding 600 kWh to the feed-in tariff that you previously accounted for as self-consumption in the electricity demand? A kilowatt-hour produced by the photovoltaic system can’t be both self-consumed and sold at the same time, right? Besides that, shouldn’t the feed-in tariff be subtracted instead of added (because it’s income, not expenses)? I’m a bit confused here.Finally, someone else who can’t follow your formulas and calculations. Great – thanks!
Vestaxx GmbH schrieb:
a storage system comes into play and static yield values are used for calculations Both support your approach, as I explained above. So a very fair calculation from @RotorMotor
Vestaxx GmbH schrieb:
Suddenly continuous text and no more tables. That should actually be convenient for you?
The one with the tables was @OWLer.
Vestaxx GmbH schrieb:
The discussion leads nowhere – so I will end it from my side now. Too bad, I would have liked to know what you think about my thesis regarding the target group.
Interrupt schrieb:
Why are you adding 600 kWh of feed-in tariff that you previously accounted for as self-consumption in the electricity demand? A kilowatt-hour produced by the photovoltaic system can’t be both self-used and sold at the same time! Besides: shouldn’t the feed-in tariff be subtracted instead of added (since it’s income, not expense)? I’m a bit confused here. Read your own text carefully again. You actually answered your question yourself. He adds the (lost) feed-in tariff to the costs. Economically correct, because this is not a cash flow analysis.
Vestaxx GmbH schrieb:
The calculation is already entirely wrong because he completely excludes the total yields of the photovoltaic system in Vx + photovoltaic, and only takes the yield that can be used directly for heating in winter. Everything else generated by the photovoltaic is simply ignored. No, not ignored. He clearly states what he does with it — that is, in both versions he accounts for the cost of the photovoltaic system.
V
Vestaxx GmbH11 Oct 2022 13:05Tolentino schrieb:
Both approaches support your version, as I explained above. So a very fair calculation by @RotorMotor
That should be in your favor, right?
The one with the tables was @OWLer.
Too bad, I would have liked to know what you think about my hypothesis regarding the target group.
Read your own text carefully again. You answered your own question. He adds the (lost) feed-in tariff to the costs. Economically speaking, that is exactly correct since this is not a cash flow analysis.
No, it’s not omitted. He clearly states what he does with it, namely that in both cases the photovoltaic system is paid for. Unfortunately, this is taking up too much of my time here, although I would like to continue the discussion. I’m out.
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