Hi Steveak512 and welcome to the neighborhood. Seems like you have a handle on it, if it were me I would see if that 2.99% rate was also applicable to other panels, but hey that's just me. I do believe you often need to pay a slight premium to deal with the best installers and it sounds like you have found a good one. I also understand the desire to get the Sunpower panels as they are made in the States and therefore support local jobs. All good sounds like you have done your homework, cheers.

Sounds sort of like you're mind is made up, the decision has been made and you're looking for confirmation of a wise choice. If I'm off track, I apologize.

Like Pete suggests, look for better financing. If the financing makes the S.P. vs. LG close, there's something not right w/the LG pricing, as in too high.

As for S.P. being more cost competitive in places w/tiered rates, CA is about 90++% tiered rates and S.P. is simply not cost competitive here. There may be local incentives in TX/Austin etc. that make solar more competitive w/POCO power, or allow a larger annual offset to be more cost effective, more cost effective, or actually make oversized systems LESS cost effective, but if system output/installed kW is about the same, regardless of S.P. or LG, or any other quality panel (and it mostly is), then the less one pays upfront per installed kW, the more cost effective the system will be, tiered rates or not.

What is a consideration under tiered rates is, as you write, not replacing the cheap stuff in the lower tiers w/ expensive solar. In that case less expensive (non S.P.) but equal output/ kW panels will be more cost effective from the standpoint of being able to replace more lower tier electricity because of the non S.P. system's lower cost. At this time, 5kW system that costs 20% less up front will be more cost effective than a 5 kW system costs 20 % more. If the financing is a deal breaker (or maker), then the up front cost difference probably isn't 20 or so % as is usual for S.P to non S.P. price differential, meaning the non S.P. price may be too high.

Obviously, you ought to do what you think best for your situation, but thinking S.P. is made more cost effective under tiered rates is a new one to me. Did some peddler B.S. you into that one ?

BTW, what's your annual usage ? Proposed Orientation/tilt ? Have you run PVWatts to verify estimated system output ?

Thanks for the feedback, guys. I must admit I'm out of my depth with the last couple of questions you ask; our usage averages 1400kWh per month. I guess I am hoping for some confirmation that this proposal is a good one, or at least is a realistic cost for this setup in this area. I do understand that sunpower is never going to be as cost effective as the other panels. And my thought on the benefits of tiered rates was not specific to sunpower, but rooftop solar in general. In any case, thanks for entertaining a newbie to this forum and to rooftop solar.

I'd suggest buying a more recent, or free downloading of a slightly dated copy of "Solar Power Your Home for Dummies." After the read, you'll be a lot less out of your depth and much better equipped to gauge the goodness of any proposal and the most appropriate equipment and size for your situation.