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
E
Elias_dee12 Aug 2022 13:11Thanks to both of you! I'm considering the storage, but I actually don't have the budget for it anymore... maybe retrofit later 🙂
@i_b_n_a_n: I wanted to ask that anyway, since I didn't understand it. I read in the datasheet that it supports up to 15 kWp. But if I have a system that can theoretically produce almost 18 kWp—why don't I need a larger inverter?
@i_b_n_a_n: I wanted to ask that anyway, since I didn't understand it. I read in the datasheet that it supports up to 15 kWp. But if I have a system that can theoretically produce almost 18 kWp—why don't I need a larger inverter?
E
Elias_dee12 Aug 2022 13:12RotorMotor schrieb:
You cannot operate the inverter on the system.
Sorry, but I would recommend finding a solar installer with expertise or seeking advice elsewhere. Why is that? What is wrong with the inverter?
R
RotorMotor12 Aug 2022 13:18The inverter only supports 10 kWp AC. That is a real waste for 17 kWp.
The next issue is that it only handles modules up to 15 kWp. The voltage would simply be too high with your number of modules.
I would recommend at least a 15 kWp inverter.
The "problem" is that most hybrid inverters only go up to 10 kWp...
The next issue is that it only handles modules up to 15 kWp. The voltage would simply be too high with your number of modules.
I would recommend at least a 15 kWp inverter.
The "problem" is that most hybrid inverters only go up to 10 kWp...
E
Elias_dee12 Aug 2022 13:19RotorMotor schrieb:
The inverter can only handle 10kWp AC. That’s really a waste for 17kWp.
The next issue is that it only supports up to 15kWp modules. The voltage with your number of modules would simply be too high.
I would recommend at least a 15kWp inverter.
The "problem" is that most hybrids only go up to 10... Ah, okay. I see. The only disadvantage of a non-hybrid is that you can’t connect a battery, right?
R
RotorMotor12 Aug 2022 13:21It just needs its own inverter. So I would revise my recommendation.
Fill the roof completely with the 20 kWp and a 20 kW inverter.
Better to skip the storage for now or add a suitable AC-coupled one later.
It might also work well for an electric car in the future.
Fill the roof completely with the 20 kWp and a 20 kW inverter.
Better to skip the storage for now or add a suitable AC-coupled one later.
It might also work well for an electric car in the future.
RotorMotor schrieb:
The inverter can only handle 10kWp AC. That’s a real waste for a 17kWp system.
The next issue is that it only supports modules up to 15kWp. With your number of modules, the voltage would simply be too high.
I would recommend at least a 15kWp inverter.
The “problem” is that most hybrid inverters only go up to 10kWp… I only read about the 15kWp limit, and since this will probably be a north/south system, that value should never be reached—or am I misunderstanding?
If the string configuration is planned and the string voltage ends up too high, the solar installer might have to revise the plan. But I would have assumed they use design software (e.g., Photovoltaik*SOL) and then choose the recommended inverter accordingly?
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