Help choosing a panel - 3 options

[adgjqetuo]

Hello -

I'm looking for advice on which would be my best pick for purchasing a solar system for my house. I'm looking to go through a program my local utility company is offering so i'm a little limited on contractors that are affiliated via their website. My past 12 months usage averaged 7,908 Kwh / 2,600 sq ft home (New Jersey).


Contractor 1:

$3.74 / Kw (Before any incentives)

- 5.985 Kw (21 Panels)
- 285 monocrystalline Hyundai Panels
- SolarEdge Inverter and Optimizers
- Extended 25 year warranty included
- 5 year contractor workmanship warranty
- 8,174 Kwh expected yearly based off estimated 8.92% loss rate (http://pvwatts.nrel.gov/pvwatts.php)
- IronRidge Standard Rail system

I personally think his estimated loss rate was a little low to try and drive up the expected output, but i'm not sure.




Contractor 2 (Option 1):

$2.95 / Kw (Before any incentives)

- 6.16 Kw (22 Panels)
- 280 monocrystalline SolarWorld Panels
- SolarEdge Inverter and Optimizers
- Extended 25 year warranty included
- 10 year contractor workmanship warranty
- 7,623 Kwh expected yearly based off estimated 13.19% loss rate (http://pvwatts.nrel.gov/pvwatts.php)
- Snap N' Rack Rail system


Contractor 2 (Option 2):

$2.85 / Kw (Before any incentives)

- 6.16 Kw (22 Panels)
- 280 polycrystalline Azitech Panels
- SolarEdge Inverter and Optimizers
- Extended 25 year warranty included
- 10 year contractor workmanship warranty
- 7,623 Kwh expected yearly based off estimated 13.19% loss rate (http://pvwatts.nrel.gov/pvwatts.php)
- Snap N' Rack Rail system


This estimate was a little more aggressive with his loss number - but i'm not sure how to figure out who is more accurate. The second contractor has more overall KWs but his estimated usage is less than my average usage which has me a little concerned - however i'm sure I could request a couple additional panels if necessary. It seems that an accurate loss number is key and i'm not sure how to get an accurate representation.

Hoping for some direction or other things to consider when making my decision.


Thank you in advance!

[J.P.M.]

Direction: First, get informed. Download and read "Solar Power Your Home for Dummies". Those prices are per Watt, not per kW. Next, get familiar with the PVWatts help/info screens, particularly the parts dealing with system losses. 14% is the default system loss rate.

Fact is, depending on what your situation is, and what some vendor might want PVWatts to come up with, the system loss parameter can be higher/lower. Also note, PVWatts output is a long term average performance estimate. Actual yearly output is stated as variable year/year by up to about 10%. My system loss parameter seems to be ~~ 6-7 % to have a PVWatts estimate sort of look like what I actually get/yr. A lot of folks around here suggest 8-10%. A lot think the 14 % default rate is too conservative. It's all an estimate anyway, +/- a lot.

The vendor's estimate #'s you're showing aren't that far apart when adjusted for the system loss parameter. Vendor 2 seems about 5% more conservative. I'd not consider that a very big deal in the overall scheme of things. I'd spend more time digging into vendor quality in the decision making process, and whether a 25-30% premium for vendor # 1 is worth it.

[adgjqetuo]

Thank you - I'll look into it.

Yes, I knew it was watt - Type-o coupled with copy and pasting . Thanks for the catch!

I'm assuming any panel brand is decent? Looking online I think I was leaning toward either the Hyundai or SolarWorld due to them both being monocrystalline. The $0.10 difference for the Poly didn't seem like that large of a cost savings.

[J.P.M.]

Thank you - I'll look into it.

Yes, I knew it was watt - Type-o coupled with copy and pasting . Thanks for the catch!

I'm assuming any panel brand is decent? Looking online I think I was leaning toward either the Hyundai or SolarWorld due to them both being monocrystalline. The $0.10 difference for the Poly didn't seem like that large of a cost savings.

Read the book and then play w/ PVWatts. There are lots of mfg. that produce good quality equipment. Don't take this as a knock, but from your posts thus far, looks like you've got a lot to learn. Do so and then come back w/ questions to fill in gaps in your newly acquired knowledge. That's on efficient way to save energy and money.

[thu292]

Contractor 2 (Option 1):

$2.95 / Kw (Before any incentives)