Interesting Comment Posted under that article
Sunpower panels are cadillacs, no doubt about it. But you need a workhorse not a luxury car. Know this: You're buying a commodity to reduce your electric bill, not a lifestyle. Comparable sized Sunpower systems (5kW for example) vs. almost any other 5 kW system will produce almost identical yearly output on your roof. But....the Sunpower system will cost about 20% more (something like $5000) in CA). Same bottom line output - higher cost. Doesn't sound financially efficient to me. The Sunpower efficiency claim mostly comes from the fact that Sunpower panels are about 20% PHYSICALLY SMALLER. Physical size has little to do with output. Systems that use other good quality panels are larger, less expensive and have virtually the same output as Sunpower systems for the same electrical size, location,orientation and load. All quality panels, Sunpower and everyone else, carry long warranties so that probably isn't much of an issue. You'll have moved or be dead by the time the panels fail. Sunpower's possible advantage is where you have limited space, but that may mean that your're oversizing your system, a common mistake vendor's are only too happy to lead you into. Remember, vendors make money by putting solar equipment on your roof - not saving you money. Some are honest - some are crooks. People are ignorant when it comes to this business. Don't be fooled by bogus claims. Do your homeowner. Get multiple quotes. Caveat Emptor !