Assistance to see if the system I'm getting would give me the kilowatts quoted

**Mike90250** · 04-03-2019, 10:45 AM

Is this a purchase or a lease system ?

You can do 95% of this yourself, with PV watts https://pvwatts.nrel.gov/pvwatts.php put in your data, and it gives you a monthly/yearly estimate.

The big question , is how will the panels be affixed to the flat roof, anchors and sealant, or ballast racks ? Who do you call when it leaks ? who pays for roof repair, and when roof needs maintenance, who removes/replaces the solar ?

**Jasper7821** · 04-03-2019, 11:06 AM

Thanks for the reply, it's going to be a purchased system for 20k before Federal/State credits. It includes 30yr warranty on the entire system and 15yr warranty on the roof.
Its going to be a rack system that they have just over 4K but that cost is included in the 20k It comes out to $3 a kilowatt and that seems to be the norm.
as far as roof maintenance (resealing every 5yrs or so) I need to check on that. Maybe like the other stuff up there now and just seal up to whatever is sticking into the roof.
Thank you for the link, I'll check that out.

**J.P.M.** · 04-03-2019, 11:40 AM

What's your zip ? As Mike suggests, run PVWatts yourself and confirm the output. Looks like from that system loss of 14.08 (I'm assuming %) you write of, someone may have already ran PVWatts.

When you rerun to verify, use 10 % system losses. Many folks find that # is a better fit for actual performance, at least in the early years of a system's life.

If you live in a vey sunny, and moderately cool climate, you may have a shot at 1,744 kWh/yr. per installed STC kW, but that's close to about as high as it gets. Example: I'm in zip 92026 and w/out shade loss I've averaged 1,805 kWh/yr. per installed STC kW.

~ $3.00/STC W seems about the going rate. I'd get a couple more quotes and spend as much time looking at vendor quality as low initial price. Buy cheap, buy twice. Once to buy, once to fix things not done right the first time.

**Jasper7821** · 04-03-2019, 11:57 AM

Thanks, the zip is 85712 Tucson AZ.
That number includes their calculated 14.08% loss and they got 11,721kW production for the year.
Stil have to look at that link but it didn't seem like an actual number.
and as far as shopping around, I did a little and was happy with my sales rep so we'll see what happens. The site survey is tomorrow and should have an exact production of kilowatts per year. As long as it has the production guarantee, I guess I'm happy.

**Jasper7821** · 04-03-2019, 12:37 PM

I used the calculator and it's pretty cool. I changed form 15 degrees to 20 and it bumped up the production 219kW to total 11,994kW. That was the number that was the default number in there. And 14.08 was the default so I left that.
soni guess my system will generate that then ?

**J.P.M.** · 04-03-2019, 12:38 PM

Originally posted by Jasper7821

Thanks, the zip is 85712 Tucson AZ.
That number includes their calculated 14.08% loss and they got 11,721kW production for the year.
Stil have to look at that link but it didn't seem like an actual number.
and as far as shopping around, I did a little and was happy with my sales rep so we'll see what happens. The site survey is tomorrow and should have an exact production of kilowatts per year. As long as it has the production guarantee, I guess I'm happy.

You will never get an "exact production of kilowatts per year".

First off, annual output is measured in kWh/yr., not kilowatts per year.

Second, you will not see the same output for any consecutive 365 day period any more than you will see the same weather for any consecutive 365 day period.

Third, and partly due to the second point above, read the fine print on any production warranty. They are full of holes and pretty much useless. Also, you or most any residential user, even if they read the production warranty, will neither understand the terms or have the equipment or record keeping necessary to verify conditions for a warranty claim.

Lastly, production warranties are strictly a marketing tool. they mean nothing in any real measure.

**Jasper7821** · 04-03-2019, 12:52 PM

Thanks, I just trying to calculate what my electric bill will be annually with the solar since I already know (if same as last year) what it will be. And I know the production will be different daily.
Im trying to see what my electric bill will be with solar added so I can justify spending the 13k after credits.
I think it's worthwhile, plus I like to help the environment when possible. I have a plug in Hybrid so i save there too.

And thanks for the clarity on KW and KWH.
Still learning all this stuff.

as far as production warranty, I'll read it thoroughly and see what I think.
And with the SolarEdge app, wouldn

Assistance to see if the system I'm getting would give me the kilowatts quoted

Assistance to see if the system I'm getting would give me the kilowatts quoted

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