Lost between the sun beams - how do I choose a solar system for my house

July 22, 2017 5:26 PM

We are fairly far along in trying to purchase a solar system for our house and I am getting dragged down in details trying to compare options - one company offers the newest and fanciest panels with micro inverters (and a higher price tag), another offers to cover our entire roof with cheaper panels using a regular inverter + optimizer, a third is somewhere in between. How do I think about this?

So, we are definitely going to be buying a new solar system this year. The quotes so far look like this:

Company A: medium-small size local company with a good reputation. Initial proposal included the newest LG 365 panels (lg365q1c-a5) and the Enphase micro inverters for system sized to meet all of our needs. As I talked to them, they added two other options: using LG-330 (lg330N1c-A5) which are not quite as good but cheaper and/or sizing the system to 81% of need.

Company B: smaller local company. Owner involved in previous solar company which got bought out by large international company, leaving behind some unhappy customers but present company has a good reputation. Proposal uses a higher number of smaller panels, Bouvet 320s (BVM6610M-275) and a standard Solar Edge inverter + optimizers. Cost is 33% cheaper than the Company A proposal using the LG365 which sounds good but makes me nervous that I might be missing something.

Company C: larger local company (serving multiple counties), good reputation, contact has been by email but responsive. Quoted a smaller (81%) system using LG 330s (LG360Q1c-A5) which seems to be also pretty advanced, but with Solar Edge inverters. The cost was between A & B. When I asked about a larger system, they said there wasn't room on the roof without facing north although the other two had no trouble finding room for more panels on the east and west facing portions.

So - my questions:
- I can compare the the different LG models pretty easily on the LG website but I get totally lost trying to figure out how the Bouviet measure up. Any resources out there?
- microinverter vs. standard? worth paying extra for?
- I'm not sure any of these companies will be around in 25 years - although larger Company C probably has the best shot. How important is the installer warranty vs. the supplier warranty 10+ years down the road? Any other things I should be considering in choosing a supplier?
- A part of me really wants to go to 100% but I would be spending an additional $5000 to save $200 a year according Company A's estimates. Can you give me a good reason to do it anyway? (We can afford if it makes sense, I'm just afraid it doesn't make sense)

posted by metahawk to Home & Garden (4 answers total)

I'll comment on your last item. Assuming your numbers are correct, spending an extra $5000 to save $200 per year has a 25 year payback. That's a pretty poor return. Typical payback rates for solar installations are 6 to 9 years. Again, assuming your calculations are right, this seems a poor value.

On the other hand, if you regard 100% coverage as a luxury item, then the extra expense may be worth it to you.
posted by JackFlash at 5:48 PM on July 22, 2017

Best answer: If you get references from these companies, how do they each behave in terms of maintenance? A newer product like micro-inverters have less of a track record. If down the line you need a panel fixed, or an inverter replaced, how do you think they will act?

For different costs of the solar system, for the same amount what sort of improvements could you make in consumption, or in house insulation to bring your total energy usage down and home comfort more?
posted by nickggully at 6:34 PM on July 22, 2017

Best answer: As I understand it, one advantage of the optimizers over the microinverter setup is that it's easier to connect battery storage after the fact. I am not sure of the details, but I think that the optimizer-based setup can charge the battery before the inverter turns it to AC, but using microinverters, you're getting AC right off the panels, so you have to convert it back to DC (with an energy loss) before you can send it to the battery. So if you are in a state currently with net metering, but there are risks that the regulations may change, you may want to consider battery storage for the future.

I interviewed three companies, similar to you, for a 34-module, 11Kw system on my roof. I also got inconsistent answers about how many modules I could install. One small company said I could only put 16 up. The others doubled that. My roof is flat, built-up tar and gravel, and I suspect the small company hadn't done many flat roofs and didn't know how to pack them in.

My choices were a growing, local, well-regarded company with several offices in the region, and a very small business. The very small business guy wouldn't even come out to survey the site. I used him for price leverage with the local company, and signed with the local company. It all went really well.

Then a year later, I lost my inverter to a lightning strike and had to replace it. See if your installers can add some additional surge protection. Might be cheap insurance.
posted by tybstar at 6:54 PM on July 22, 2017

Response by poster: So, the best answer was "Get a quote from Company D" - I reached out for one more quote and got one that was overall clearly better than the others. I did find nickggully's question about how else we could use the money a helpful reminder to keep an eye on the bigger picture and tybstar's comments about optimizers made me more comfortable with the Company D quote to use them. (I think there is a good chance that net metering may become less attractive as more and more solar comes on-line.)
posted by metahawk at 8:30 AM on July 29, 2017