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
driver55 schrieb:
Sorry, that’s practically impossible. That would mean about 3650 kWh per year without cooking, dishwasher, ironing, hairdryer, TV, home office, etc.
So it can’t be...
That much standby consumption... 🙄 Honestly, I don’t really know what to make of your comments. I measured it over the course of a week, and it was definitely 10 kWh. As I have mentioned several times, when you’re not home, the following things still run in addition to the usual ones like the refrigerator:
Ventilation
Robot mower and house
Standby TV, printer, PC, laptop, game console
Outdoor lights occasionally due to building management system
Descaling system
Air-to-water heat pump
Garden irrigation (the pump for it)
Fully automatic coffee machine standby
Video doorbell
Fingerprint sensor
So yes, that is clearly a lot more than in, for example, an apartment.
I also mentioned that the consumption dropped to 3 kWh daily after we unplugged 2 laptops, printer, the 3 TVs, and the console...
And if you had read carefully, you would know that the standby consumption is now 3 kWh after this action.
R
RotorMotor15 Aug 2022 14:43Snowy36 schrieb:
and I had also mentioned that consumption dropped to 3 kWh daily after we disconnected 2 laptops, a printer, the 3 TVs, and the console from the power supply... Were the devices mentioned running continuously before, or were they in standby mode?
RotorMotor schrieb:
Were the devices mentioned here running continuously before, or were they in standby mode? They were in standby mode.
2 laptops, each with a screen.
3 TVs.
Fully automatic coffee machine.
Xbox.
Wi-Fi printer.
I guess a 65-inch OLED TV uses quite a bit of power in standby... but I didn’t want to measure each device individually or anything like that. I’ve now set it up so I can turn each device completely off, which has reduced the power consumption.
R
RotorMotor15 Aug 2022 15:10Snowy36 schrieb:
They were running in standby mode.So, were they running or were they in standby?A device in standby typically consumes about 3W (and that would actually be on the high side. Most devices should be under 1W).
Here there are about 12 devices, so a maximum of 36W.
Over 24 hours, that’s 0.8 kWh. Annoyingly high, but still a factor of 10 less than your 7 kWh.
So it’s safe to assume that one or more devices were not in standby but actually running.
Maybe not even one of those mentioned, but something else entirely, and it was just a coincidence.
RotorMotor schrieb:
So, were the devices running or in standby?
In standby mode, a device typically consumes about 3W (and that's already on the high side; most devices should be under 1W).
Here you have around 12 devices, so a maximum of 36W.
Over 24 hours, that’s 0.8 kWh. Quite a bit, but still a factor of 10 less than your 7 kWh.
So it’s likely that one or more devices were not in standby but actually running.
Maybe none of those mentioned, but something else, and it was pure coincidence. Well, I wasn’t home, so none of the devices were turned on, only in standby. To find out which of the 12 actually used power, I’d have to measure all of them.
The large TV alone uses 40W in standby. I already looked into the settings and changed some to reduce that.
Right now we’re at home and use 11 kWh per day.
I thought that was a lot, but I got feedback here in the forum that others have the same. What surprises me is that electricity providers estimate about 2700 kWh per year for two people, and I have friends and neighbors who reach that.
However, they don’t have all the extra devices I listed.
When I’m bored, I’ll measure the devices.
R
RotorMotor15 Aug 2022 15:24Snowy36 schrieb:
Well, I wasn’t at home, so none of the devices were fully on, just in standby mode. To find out which of the 12 devices is actually consuming power, I’d have to measure them all. The large TV alone uses about 40W in standby. I have already adjusted some settings to change that.
Currently, we are at home and use about 11 kWh daily. Please measure everything carefully again. So far, the statements are very confusing for other readers.
A TV never consumes 40W in standby mode. That is actually not allowed. Sometimes OLEDs perform some kind of refresh activities, but that only lasts for about an hour, not 24/7.
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