We have a pretty aggressive state incentives on solar installs (which are being phased out/lowered over the next few years). I have been considering solar for quite some time and have the following two systems quoted to me. We also have one of the lowest rates for purchased kWh (about .10), but net billing, for now anyway, helps speed up the ROI. Both quoted cost almost exactly the same, $25K before incentives, $5K net out of pocket. Which deal is better?
There are some definite intangibles, such as are micro inverters better/worse than string inverters, which is the better panel, USA made vs. USA assembled, brand names, aesthetics on what may be mounted by the meter (string inverter vs. nothing when using micro invertors), BS factor of sales person, possible inflated/padded numbers on quote, etc..
Here are the basics (all their calculations/claims):
17 - 265 watt Solar World PV panels (15.8% efficiency?)
17 - Enphase microinverters
4.5 kw system
496 kwh production/month
No out of pocket ("free" bridge loan) - when asked to break out the loan - it results in an approximate net savings less than $300
18 - SunPower E19 320 watt PV panels (19% efficiency?)
1 - SunPower 5000m inverter
5.76 kw system
717 kwh production/month
50% due at contact signing ($12,500) and 50% due upon completion
Due to the fact, that if looked at strictly in terms of net production for the $ outlay - I supposed System 2 is the clear winner. However, if that were the only consideration, there are cheaper panels and inverters (and companies that will quote labor lower) - so I am trying to look beyond that. I believe both quotes are on reputable product and from generally reputable local firms.
The way I see it, there are at least 3 main levels or sets of decision points, and of course quite a few potential subsets, depending on individual circumstances and preferences.
The first one is the stated specs of a given system, which should be relatively accurate for comparison purposes (controlled conditions testing). Assuming one is looking at a relatively known company that has track record of at least a few years. I believe the brands I have listed above fit this description - recognized as reputable and arguably in the Top 10 (or 15) or so in panels/inverters.
The second level is based on the contractor/company doing the installation. Let's face it, this can be just as important, or more so, that the first level. If you have great product but a sketchy contractor, and there are problems, and they won't fix them - you still have a system that is not earning back your investment while you deal with that. So, top rated product, with a questionable install company can be a poor decision - compared to a slightly lower rated product with a solid installer behind it. Does the installer have the track record and means (and willingness) to fix problems quickly? Do they have a solid financial base to weather a manufacturer that has a bad batch of panels - that will force them to finance the corrections until they get reimbursed for warranty work? Will they be around in 10 years to support that 10 or 25 year warranty that makes us feel good at the contract signing? Is the salesman credible? Do they present distorted/inflated or wishful thinking numbers to get you closer to signing? While they may not be lying, and even though you only probably only have to deal with the salesman now - it is probably indicative of how the company as a whole operates - they hire and train the guy - so they are supporting what he says/does/promises.
The third level, is based on personal preferences and financial needs. Is made in the USA worth anything to you? Do you need/want financing for the system? Do aesthetics affect your decision (look of the panels, inverter on outside wall), etc....
The main reason I suppose I am posting this (other than for some great incite from a vast amount of knowledge/opinions of the product brands and types out there to supplement my limited solar knowledge) is to force me to walk through all these factors and come closer to a decision.
Bottom line, System 1 seems to produce 29% less electricity, but I lean toward it for 100% USA made panels, micro inverters preferred, numbers presented are much more realistic/conservative (i.e. trustworthy sales pitch - personal pet peeve when someone exaggerates excessively). However, System 2, compared to System 1, will get a faster payback - no matter how you slice it, right?
SunPower seems to be acknowledged to be toward the top of the panel producers, no? Of course Solar World seems to be recognized as high quality as well.
Let me know what you guys think about the brands and/or whether the numbers seem reasonable - and any other things I have missed.