Good morning,
Yesterday, we received a quote for a photovoltaic system. Our construction of the single-family house will start in October 2023 and is expected to be ready for occupancy in September 2024.
We have an annual electricity consumption of about 3000 kWh for our household, plus an unknown amount for the air-to-water heat pump (Weishaupt Biblock).
Our roof is oriented exactly south with a 25° pitch (gable roof). According to the calculation in the quote, the entire south roof is fully covered with modules (20 units), and the north roof is also equipped with 5 modules.
Attached you will find the details of the quote. The price is €20,900 net with battery storage and €15,900 net without storage.
What do you think of the offer? From what I understand in the discussions here on the forum, it is advisable to skip the battery storage. That would bring the cost to just under €16,000, which is a bit over €1,600 per kWp. That seems relatively expensive, doesn’t it?
Thank you very much in advance for your help.
Best regards,
Elias
Yesterday, we received a quote for a photovoltaic system. Our construction of the single-family house will start in October 2023 and is expected to be ready for occupancy in September 2024.
We have an annual electricity consumption of about 3000 kWh for our household, plus an unknown amount for the air-to-water heat pump (Weishaupt Biblock).
Our roof is oriented exactly south with a 25° pitch (gable roof). According to the calculation in the quote, the entire south roof is fully covered with modules (20 units), and the north roof is also equipped with 5 modules.
Attached you will find the details of the quote. The price is €20,900 net with battery storage and €15,900 net without storage.
What do you think of the offer? From what I understand in the discussions here on the forum, it is advisable to skip the battery storage. That would bring the cost to just under €16,000, which is a bit over €1,600 per kWp. That seems relatively expensive, doesn’t it?
Thank you very much in advance for your help.
Best regards,
Elias
Zubi123 schrieb:
I wouldn’t fully agree with that… regarding the feed-in tariffYou don’t have to. But having it for 11 months more or less—almost a whole year—does make a difference. Of course, everyone can decide that for themselves. Just a recommendation. 😉Deliverer schrieb:
For that, a full north-facing array, or at least a full string (usually about 20 modules), is needed. With such a low roof pitch, it is worth it.Up to what roof pitch is it worthwhile to install panels on a north-facing roof?D
Deliverer22 Apr 2022 18:30That often depends on many factors. The most important is the purchase price—specifically, the additional cost for a north-facing installation. This is often not very high, since the inverter hardly becomes more expensive, the electrician’s expenses remain the same, and the paperwork does not increase either. You just need to get this information from the solar installer, preferably by requesting a detailed, itemized quote where only the roof mounting, modules, and supporting structure for the additional north-facing section are added.
In short: I would install panels on roofs up to 25° tilt immediately. In southern regions, up to 30°. If the north-facing roof is actually rotated about 20° towards east or west, a few more degrees are also acceptable. And if you are building yourself (for about 700 euros per kWp), then practically every north-facing roof is worth it.
If you want, you can also recalculate this on that one EU website, which cannot be mentioned here: everything above 700 kWh per year per installed kilowatt is considered profitable.
Heat pumps further increase the benefit of a north-facing installation because winter’s cloudy, damp weather yields a similar (low but useful) energy output regardless of roof orientation.
Another advantage: Anyone with a properly shaded, unshaded south-facing roof will often hit the 70% feed-in limit. Adding a north-facing section usually prevents any curtailment from occurring.
In short: I would install panels on roofs up to 25° tilt immediately. In southern regions, up to 30°. If the north-facing roof is actually rotated about 20° towards east or west, a few more degrees are also acceptable. And if you are building yourself (for about 700 euros per kWp), then practically every north-facing roof is worth it.
If you want, you can also recalculate this on that one EU website, which cannot be mentioned here: everything above 700 kWh per year per installed kilowatt is considered profitable.
Heat pumps further increase the benefit of a north-facing installation because winter’s cloudy, damp weather yields a similar (low but useful) energy output regardless of roof orientation.
Another advantage: Anyone with a properly shaded, unshaded south-facing roof will often hit the 70% feed-in limit. Adding a north-facing section usually prevents any curtailment from occurring.
Much has already been said, especially regarding the use of the north side. At a 25° angle, I wouldn’t hesitate for a second.
SolarEdge usually costs more. The wiring effort is higher, and there is more electronics on the roof. The very long warranty with SolarEdge often does not justify the additional cost. I also don’t see any added value in the module-level monitoring possible with SolarEdge. The five standalone modules on the north side, of course, operate with SolarEdge; with “normal” inverters, such a short string usually won’t start, especially on the north side. But since I would fully occupy the north side anyway, that argument becomes irrelevant. 😉
SolarEdge usually costs more. The wiring effort is higher, and there is more electronics on the roof. The very long warranty with SolarEdge often does not justify the additional cost. I also don’t see any added value in the module-level monitoring possible with SolarEdge. The five standalone modules on the north side, of course, operate with SolarEdge; with “normal” inverters, such a short string usually won’t start, especially on the north side. But since I would fully occupy the north side anyway, that argument becomes irrelevant. 😉
E
Elias_dee22 Apr 2022 20:19Hi everyone, first of all, I want to thank you all for the many helpful comments. As a layperson, you just hope that the solar installer / electrician knows their craft and offers / sizes everything correctly, but apparently that’s not always the case. 😉
I will go through everything again carefully over the weekend, but here’s what I’m taking away so far:
- Rather omit the battery storage
- Max out the roof
- Definitely install more panels on the north side of the roof than currently planned
--> Is that correct?
PS: Our house roof is actually aligned almost exactly north/south… the deviation is about 7-8 degrees.
I will go through everything again carefully over the weekend, but here’s what I’m taking away so far:
- Rather omit the battery storage
- Max out the roof
- Definitely install more panels on the north side of the roof than currently planned
--> Is that correct?
PS: Our house roof is actually aligned almost exactly north/south… the deviation is about 7-8 degrees.
E
Elias_dee22 Apr 2022 20:22Oh, and one more thing I wanted to add: according to the development plan, photovoltaic/solar panels are explicitly allowed as a standalone roof covering... but somewhere I read that you should still use tiles and then install the system on top. Deliverer mentioned something about metal instead of tiles. That would basically be a photovoltaic roof covering, more or less, right?
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