ᐅ Roof Covering and Choosing a Solar Installer – Making the Decision?
Created on: 10 Aug 2022 18:21
E
Elias_dee
Hello everyone,
I am about to decide whether to hire a solar installer. I am building a turnkey single-family house with a general contractor in the 84xxx area, featuring a gable roof with a 25° pitch, oriented north/south. There are no skylights, chimney, or other obstructions on the roof, so conditions are optimal.
I am having some difficulty even requesting quotes and now have at least two offers. I would appreciate help evaluating and choosing between them (both the company and whether to include the north side). I have not asked for a battery system but might consider adding one later if it becomes more affordable.
So, first I am facing the question: include north side or not? I can fit about 25 modules on each side, resulting in roughly 10 kWp. PVGIS estimates around 10,000 kWh for south and about 7,000 kWh for north.
Offer 1 comes from a solar installer with many years of experience, who not only works on single-family houses but also builds large-scale systems in the megawatt range. My general contractor, who is building the house turnkey, also has long-standing experience with this installer and recommends them.
Offer 1 details:
- 20.5 kWp
- 50 x Q-Cells Q-Peak ML G10 410 heat pump compatible modules
- 50 x SolarEdge Power Optimizers, S440 Worldwide (v1)
- SolarEdge StorEdge three-phase inverters: SE10K-RWS-EU-APAC/AUS (v1) and SE7K-RWS-EU-APAC (v1)
- SolarEdge Smart Meter for self-consumption monitoring
- All other materials, installation, and commissioning services included
- Cost: €31,980 net, which equals approximately €1,560 net per kWp — reasonable for today, not really cheap but not very expensive either
Now to Offer 2. This offer is from a very small and new electrical company I found through a neighbor's recommendation. The company does not even have a finished website yet because it is so new, but they have already done electrical work in the development area (not sure about PV though). Two different neighbors have told me this company is good.
Offer 2 details:
- 20.9 kWp
- 51 x JinkoSolar Tiger NE HC N-Type black solar modules JKM410N-54HL4-B
- 2 x SMA inverters STP10.0-3SE-40
- 1 x SMA Sunny Home Manager HM-20
- Other materials are not specified here, but all installation, planning, and commissioning services are included
- Cost: €25,570 net, equaling approximately €1,223 net per kWp
My questions now:
- What do you generally think about the materials used?
- Are the SolarEdge power optimizers in Offer 1 really necessary? I expect practically no shading from trees, chimney, or anything else given the location
- Company 2 is probably a bit risky, but the price is really attractive. Is it worth taking the risk here?
- Does installing modules on the north side make sense at all in the case of Offer 1? If I calculate north and south separately, south obviously makes sense in both cases. North seems worthwhile (based on my calculation) only with Offer 2... with Offer 1 I would be running at a loss.
I would be very grateful for a brief assessment!
Best regards
I am about to decide whether to hire a solar installer. I am building a turnkey single-family house with a general contractor in the 84xxx area, featuring a gable roof with a 25° pitch, oriented north/south. There are no skylights, chimney, or other obstructions on the roof, so conditions are optimal.
I am having some difficulty even requesting quotes and now have at least two offers. I would appreciate help evaluating and choosing between them (both the company and whether to include the north side). I have not asked for a battery system but might consider adding one later if it becomes more affordable.
So, first I am facing the question: include north side or not? I can fit about 25 modules on each side, resulting in roughly 10 kWp. PVGIS estimates around 10,000 kWh for south and about 7,000 kWh for north.
Offer 1 comes from a solar installer with many years of experience, who not only works on single-family houses but also builds large-scale systems in the megawatt range. My general contractor, who is building the house turnkey, also has long-standing experience with this installer and recommends them.
Offer 1 details:
- 20.5 kWp
- 50 x Q-Cells Q-Peak ML G10 410 heat pump compatible modules
- 50 x SolarEdge Power Optimizers, S440 Worldwide (v1)
- SolarEdge StorEdge three-phase inverters: SE10K-RWS-EU-APAC/AUS (v1) and SE7K-RWS-EU-APAC (v1)
- SolarEdge Smart Meter for self-consumption monitoring
- All other materials, installation, and commissioning services included
- Cost: €31,980 net, which equals approximately €1,560 net per kWp — reasonable for today, not really cheap but not very expensive either
Now to Offer 2. This offer is from a very small and new electrical company I found through a neighbor's recommendation. The company does not even have a finished website yet because it is so new, but they have already done electrical work in the development area (not sure about PV though). Two different neighbors have told me this company is good.
Offer 2 details:
- 20.9 kWp
- 51 x JinkoSolar Tiger NE HC N-Type black solar modules JKM410N-54HL4-B
- 2 x SMA inverters STP10.0-3SE-40
- 1 x SMA Sunny Home Manager HM-20
- Other materials are not specified here, but all installation, planning, and commissioning services are included
- Cost: €25,570 net, equaling approximately €1,223 net per kWp
My questions now:
- What do you generally think about the materials used?
- Are the SolarEdge power optimizers in Offer 1 really necessary? I expect practically no shading from trees, chimney, or anything else given the location
- Company 2 is probably a bit risky, but the price is really attractive. Is it worth taking the risk here?
- Does installing modules on the north side make sense at all in the case of Offer 1? If I calculate north and south separately, south obviously makes sense in both cases. North seems worthwhile (based on my calculation) only with Offer 2... with Offer 1 I would be running at a loss.
I would be very grateful for a brief assessment!
Best regards
Elias_dee schrieb:
the total annual consumption of our household. So 10,000 in total.How do you end up with 10,000 kWh for a "KfW48-200sqm (2,153 sq ft) house"? 🙄 (Without an electric heating unit). Even if it is located in cold Bavaria.
The 10,000 kWh is just an estimate since the building is not yet completed. We also initially found it very difficult to estimate our total future electricity consumption during the planning phase.
Here are my current comparison figures, which might be interesting for others as well:
Period from October 21, 2021 to August 11, 2022:
6.5 kWp system, oriented 100% south / 45°, about 130 m² (1400 sq ft) divided into 2 residential units, ground source heat pump, 2-3 people living in the two units. Fully electric vehicle since November 2021 (BEV) with about 1000 km (620 miles) per month and consumption of around 18 kWh per 100 km (62 miles).
Generated: 7,069 kWh
Consumption: 6,809 kWh
Self-consumption: 3,207 kWh
Feed-in to the grid: 3,226 kWh
Grid purchase: 3,602 kWh
Self-consumption rate for the year 2022 only: approximately 51%
Here are my current comparison figures, which might be interesting for others as well:
Period from October 21, 2021 to August 11, 2022:
6.5 kWp system, oriented 100% south / 45°, about 130 m² (1400 sq ft) divided into 2 residential units, ground source heat pump, 2-3 people living in the two units. Fully electric vehicle since November 2021 (BEV) with about 1000 km (620 miles) per month and consumption of around 18 kWh per 100 km (62 miles).
Generated: 7,069 kWh
Consumption: 6,809 kWh
Self-consumption: 3,207 kWh
Feed-in to the grid: 3,226 kWh
Grid purchase: 3,602 kWh
Self-consumption rate for the year 2022 only: approximately 51%
D
DaGoodness11 Aug 2022 14:52Above all, a self-consumption of 2,000 kWh would be somewhat low. Have you done a cost calculation yourself to see how profitable the system would be?
With an annual consumption of 10,000 kWh, annual generation of 17,000 kWh, and only 2,000 kWh self-consumption, I would roughly estimate savings of around €1,500 per year. In that case, the system wouldn’t really pay off.
I would guess that you should aim for at least 4,000–5,000 kWh self-consumption, if not a bit more.
Regarding the price, I would definitely lean towards company 2. Being small and new doesn’t necessarily mean anything. Once the system is running, they will have earned their money.
With an annual consumption of 10,000 kWh, annual generation of 17,000 kWh, and only 2,000 kWh self-consumption, I would roughly estimate savings of around €1,500 per year. In that case, the system wouldn’t really pay off.
I would guess that you should aim for at least 4,000–5,000 kWh self-consumption, if not a bit more.
Regarding the price, I would definitely lean towards company 2. Being small and new doesn’t necessarily mean anything. Once the system is running, they will have earned their money.
We have a smaller house with similar conditions and also use 8,000 kWh, so why would an additional 2,000 kWh be unrealistic with about 40 m² (430 ft²) more space? There are only 2 of us … does he have 4 occupants or something extra like a jacuzzi or something else? Could that explain it?
i_b_n_a_n schrieb:
The 10,000 kWh are just an estimate since the building is not finished yet. We also had a hard time estimating our total future electrical consumption at the beginning of the planning phase.
Here are my current comparison figures, which might be interesting for others as well:
Period from 10/21/2021 to 08/11/2022:
6.5 kWp system, 100% south-facing / 45° tilt, about 130 m² (1400 sq ft) across 2 residential units, ground-source heat pump, 2-3 people living in the 2 units. Fully electric vehicle since 11/2021 (BEV) with approx. 1000 km (620 miles) per month at around 18 kWh per 100 km (62 miles) consumption)
Produced: 7069 kWh
Consumed: 6809 kWh
Self-consumption: 3207 kWh
Feed-in to grid: 3226 kWh
Grid consumption: 3602 kWh
Self-consumption rate for 2022 alone: almost exactly 51% Great figures, but they don’t help anyone and especially don’t answer my question.
And of course, you can roughly estimate the demand in advance.
Snowy36 schrieb:
We have a smaller house with similar conditions and also consume 8,000 kWh, so why should an additional 2,000 kWh be unrealistic for about 40 m² (430 sq ft) more? We’re only two people… does he have four residents or something extra like a jacuzzi or who knows, it might add up. Yeah, sure. Wasting 8,000 to 10,000 kWh (pointless) and then being scared (surprised). Keyword “power outage.” 🙄
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