ᐅ Photovoltaic system in a new build: Would you install one? Any experiences?
Created on: 27 May 2018 10:44
S
Skyfire
Hello everyone,
I am in the final stages of planning my house.
Here are the key details of the building:
- Location: Low mountain range
- House: Timber frame
KFW 55 --> Qp = 40.9 kWh/m² and H′T = 0.259 W/(m²K)
Thermal bridge loss = 0.038 W/(m²K)
Usable roof area: approx. 40 m² (430 sq ft)
- Roof pitch: 35 degrees gable roof
- Orientation: Southeast
- Roof window: 1 centered
- Heated building volume: 497.9 m³ (17,580 cu ft)
- Usable floor area: 159.3 m² (1,714 sq ft)
The heating system will be an air-to-water heat pump and a central controlled mechanical ventilation system with heat recovery.
At the moment, I am considering the possibility of installing a photovoltaic system.
Putting ecological considerations aside and focusing purely on economic factors, is a photovoltaic system worth it in the long term? Does it make sense to try to reduce heating and electricity costs with such a system?
I think the payback time will be quite long, and it provides the least output in winter when the heat pump consumes the most energy.
What are your thoughts on installing such a system? Would you build one?
Thank you very much.
Best regards,
Steffen
I am in the final stages of planning my house.
Here are the key details of the building:
- Location: Low mountain range
- House: Timber frame
KFW 55 --> Qp = 40.9 kWh/m² and H′T = 0.259 W/(m²K)
Thermal bridge loss = 0.038 W/(m²K)
Usable roof area: approx. 40 m² (430 sq ft)
- Roof pitch: 35 degrees gable roof
- Orientation: Southeast
- Roof window: 1 centered
- Heated building volume: 497.9 m³ (17,580 cu ft)
- Usable floor area: 159.3 m² (1,714 sq ft)
The heating system will be an air-to-water heat pump and a central controlled mechanical ventilation system with heat recovery.
At the moment, I am considering the possibility of installing a photovoltaic system.
Putting ecological considerations aside and focusing purely on economic factors, is a photovoltaic system worth it in the long term? Does it make sense to try to reduce heating and electricity costs with such a system?
I think the payback time will be quite long, and it provides the least output in winter when the heat pump consumes the most energy.
What are your thoughts on installing such a system? Would you build one?
Thank you very much.
Best regards,
Steffen
Theoretically, with 300-watt modules, you could fit 7.27 kWp on your roof. In practice, it will be less because the modules have specific dimensions, and you might also have a dormer, a satellite dish, possibly snow guards, etc. So, you can expect around 6.5 to 7 kWp. Depending on the roof’s orientation, you will likely generate between 6,500 and 4,500 kWh per year from the roof. You will consume about 3,500 kWh yourself, and the rest will be fed back into the grid. The photovoltaic system will hardly produce anything for the air-to-water heat pump from early November to late February, as very little solar energy is available during those months.
H
hampshire17 Jun 2018 14:11We have decided to install a photovoltaic system. For aesthetic and technical reasons, we chose a nearly invisible solution with solar roof tiles from Autarq. The focus is on self-consumption, fire-safe low-voltage technology on the roof, and independence during power outages. Overall, for environmental reasons, we aim to produce more energy annually than we consume. During the summer months, we feed surplus electricity into the grid, while in winter we purchase some additional energy.
Skyfire schrieb:
Putting ecological considerations aside and looking purely at the economic aspect, is a photovoltaic system worth it in the long run?Actually, not really, since solar panels lose efficiency over time, inverters might fail, and batteries don’t last forever and are expensive. If you take full advantage of all available tax incentives (definitely take out a loan) and are lucky with the reliability of the components and electricity retail prices keep rising substantially (including all taxes, fees, surcharges, etc.), you might just break even.
But having a good feeling about it is worth something too. Besides, what kind of car do you drive? Many people spend a lot of money on unnecessary driving dynamics, power, or style without even thinking about it. A Porsche 911 never pays off financially; it just makes life more fun in the meantime.
For example, I spent 17,000 euros for a 6.2 kWp system with a 6.3 kWh battery, and I’ve been thrilled with it for the past two weeks, seriously—but I will probably never see that money again. Hobbies always cost...
Here again for illustration: This system has been in operation for 10 days, but we are not yet living in the house. The low consumption is only from the tools and equipment used by the contractors. So far, the system has “earned” about €2.30 per day through feed-in; you can do the math yourself...
hampshire schrieb:
We have decided to install a photovoltaic system. For aesthetic and technical reasons, we chose a nearly invisible solution with solar roof tiles from Autarq. The focus is on self-consumption, low-voltage technology on the roof that can be extinguished with water, and independence during power outages. Overall, for environmental reasons, we aim to produce more energy annually than we consume. In the summer months, we feed surplus electricity back into the grid, while in winter we purchase some electricity. Could you provide us with some information about the costs?
H
hampshire17 Jun 2018 18:01Unfortunately, I cannot provide the exact amount (I promised this to our supplier). I estimate that a 10 kWp photovoltaic system with similar technical specifications, using standard panels and typical mounting, can be obtained for 25-30% less. More detailed information is available from Autarq.
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