I am building a house here in sunny Carbondale, Colorado in a few months. We have a great rebate program available to us here that enables me to install a 6KW system on my rooftop for about 1/3rd of the actual cost with cheaper panels! This will be my second system, so I am fairly familiar with some of the basics of PV. I had Sun Power for my first array 10 years ago at a previous home. However one thing I am not sure of now is with all the new "economy" panels that are out there now, is it worth the extra money to spend more and get a superior panel like Sun Power or should I save that additional money for other improvements in the house?? Most of these panels still have between 15 to 25 year warranties for what that is worth. I could probably save about 5k by doing the economy line versus Sun Power with two of the vendors I have talked to here in town. When I say economy I mean names like, Conergy, REC and Sunriva are the other models I have looked at among a few others. Any experience out there with the "Cheap" panels? Last point I should note is that south roof space is not a big issue, as I have just enough space for the larger and cheaper "economy" panels versus getting the smaller footprint Sun Powers.

i was faced with a similar question. At first blush, I thought, of course I want the most efficient model. But I came to realize I really wanted the biggest bang for my buck. I was unsure if a 3.5KW system was all I would need, or if a bigger system would be required. 3.5 KW fits on the roof; a bigger system does not. But with 3 acres, any size ground mount was possible. If I wanted to pre-pay electrical needs of some future additions (car, guest rooms) the ground mount was the only solution. At this point adding a couple of panels at a lower cost to offset the efficiency of the Sunpower was a no-brainer.
Deciding what to do with the extra money is the real challenge. What options do you have? How much do they cost? How much does it save? How does it look? Yes, my wife wants the house to look good. But gathering and analyzing the data as to best options requires more thought and education. As you have stated, it is hard to know how any of the panels will perform; there is no established performance record. What is the guarantee? How strong is the financial status of the warantor? Will they be around in 20 years?
I'm lucky; I'm building new. Adding $3,000 of air-sealing to framing is easy, at least if it's done before siding goes up. For me, air-sealing and insulation and LED lights, mini-split heat are all low lying fruit. On an existing house, much less so.

Yea I pretty much agree with you here. My only worry was that in 5 or 10 years the performance of these newer, cheaper panels might be WAY less than they have predicted them to be and then if the company is out of business, what do you do? You are stuck! Anyway, I am looking at about a 4k, maybe 5k net difference in going with the Sun Powers versus the cheaper panels, after all the rebates I can get.

I was figuring I could put that money towards additional insulation or mini-split, air sealing, etc. like you said versus paying more for the Sun Powers and then having less money to spend on other things in the house. And yes it is a new home I am building. Depending on where electricity rates go, the increased production of the Sun Powers might produce $45 a year on the low end to maybe $100 a year more on the high end after 5-10 years into the panel life due to the decreased rate of production of the Sun Powers as opposed to cheaper ones like Conergy, Sunriva, Hyundia, etc. With a small projected economic increase like that, I don't see it being worth it unless my projections of 1% loss per year are actually higher than that of if rates sky rocket beyond a very small increase like we have seen here over the past 10 years. But only time will tell..... Cheers!

here's my take on it, I know last input I gave you did not make any sense maybe this will.
I think solar is definitely worth it but not the way it is commercially implemented, take for example lighting, if you're thinking incandescent forget about solar:
most efficient lighting devices available are LEDs no secret there, your average white LED works most efficiently at about 3.5v, your average solar panel has a nominal output of 18v open, each cell is about 0.5v x 36 in series.

commercially a panel charges a 12v battery, than through an inverter makes 115v to go to the light/grid tie which itself has a built in power supply to bring it back to 3.5v DC to light the led, all these changes are about 90 % efficient do the math, not to mention all these pieces of equipment are not cheap and inverters for example cheeping out on is a bad idea having to replace them so often versus a good quality expensive inverter.

ideally for lighting I'd like a custom panel for say a nominal 5v open 10s cells, to charge a LiFePo4 pack to a nominal 3.6v which can directly power the lights completely off grid, lot less equipment and expense, where your lighting circuit will actually be a 3.5v saving even more in wiring, same for the other appliances, you laptop for example depending on type has a battery at about 10.8v, your tv same thing operates on low volt DC both these employ a power supply to convert the 110v outlet to the proper dc voltage, solar panels make dc voltage in the first place, same goes for your refrigerator the are 24v dc available, list goes on but I am sure I lost you already, not even the installers you spoke with could keep up so far.

the point is having every appliance plug in to a standard 115v is inefficient, and solar is considered not so powerful source, the common solution has been to get more panels more inverters, etc bit of a rough approach, but it works for the installer because you need three times the equipment for the same demand. further more if you do not consider what kind of light bulbs, appliances you'll be purchasing

I actually know my stuff here but I'll leave it at that, to answer your question, I thing a better crude approach would be to initially concentrate your efforts towards energy efficient appliances, the utility company can supply you with cheaper electricity than you can especially if you consider installer profit and labor, put your money towards the most efficient fridge and ac unit you can get those are the 2 big ones, same with everything else, you'll get a lot more bang for the buck this way. And maybe in the aftermath consider solar, after you reducer your demand to the absolute minimum money can buy.

George

On my last, 1977 house, I had an array and the property had several small motors consuming probably 30-40% of my total power production. In addition, over half the bulbs in the house were incandescent. I never once had a power bill after I installed the array for over 7 year duration that I was there. I got to tell you, I don't think you telling someone to forget solar because their home may have some old style bulbs is flat out incorrect. .

However in my new upcoming home, I hope to do some LED and mostly CFL depending on location. However to go in and put in different circuits for 12 V and then having to buy or alter appliances, TV, computer, etc. to get them to run on 12volt is not something I am going to do, neither is 99% of the public. I plan on probably selling the home in 10 years and cannot see the general public accepting a home that is grid tied, but with a 12 volt wiring system. In addition, this really limits you in certain applications. I come from a large family of electricians and electrical engineers. I have personally worked as an apprentice for MUCH longer than I had wanted to, so I do know a few things about electricity and there is plenty of reasons why we use 115/120 volt and not 12v or 24v.

I am going to install a grid tied solar array and will probably have a few incandescent lights in the home where it doesn't make sense to spend 50-60 bucks per bulb. However, it WILL work just fine and I WILL not have a power bill whatsoever nor will I have a cheap inverted in which to replace in a few years. The only thing that will be "less expensive" will be the panels themselves.

Thanks for the input, but this house is grid tied and will not be using tandem wiring circuits, battery packs, etc. for many reasons. My initial post was intended on asking people what their thoughts were on panels, not 12 volt systems and no, you didn't lose me at all. And in closing, I would (or suggest at least) that you don't talk down to the next person that you reply to on a post.:))) That doesn't do anyone any good.

that was not my intention at all, neither was I aware of your background, hence I honestly thought you may not follow, I do agree that 99% of the population wont take to such setup, it was only natural to assume you are part of the 99, we're creatures of habits, despite your background yourself missed the entire point, your previous house could have done with a lot less array had the load been reduced, I know you understand that, you may not have had an electric bill but the loan on that setup may have put a dent, in other words regarding panel choice go for the good stuff get less and spend your money towards energy efficient appliances, you'd accomplish the same result rather than get a lot of cheap panels to keep up with a load that had no consideration. I will tell you this much you are obviously stuck in your old ways, no sense me bringing stuff up, you only get defensive, you know what you want go for it. just keep into consideration equipment cost if you want to compare apples for apples, takes a lot more solar cells to power a incandescent bulb in comparison to an efficient one, hence I would not consider renewables until the load is addressed, that was actually good advice and you should know that much.

Sure my last house could have got by with a lesser load, yea if I had wanted to rip the walls apart or cut a shit load of sheet rock, replace all the existing appliances, etc. and re-wire most of the house and incur all kinds of expense and labor that I would have never recovered on resale 7 years later. The house was existing, what didn't you understand there? Almost all of the "green " things that I DID choose to do on that old house, were NOT taken into account in any fashion whatsoever on resale. This seems to be a fact that many people in this forum miss. Ask anyone that went huge on building a green house 10 years ago and then sold it recently. You will hard pressed to find any that didn't take a bath on the house in all probability. IN addition, I WILL BE taking into account the load in many different aspects on the NEW house, but having a handful or so of old style bulbs is not going to send the load thru the roof, for crying out loud.

The reason I got defensive, is because you were talking down to me. In the first paragraph or so you said you had already lost me and the topic you were speaking of what not difficult at all to understand. Don't make an assumption that the other person is ignorant to the matter regardless of topic. I am just telling you, saying things like to a someone you don't even know can be quite insulting to the other person. I know I would never make a statement like that, ever. Word choice in electronic communication is key. I used to make a large portion of my living from it for about 12 years and during that time I earned a very handsome living as a result. But each to their own I guess.

Anyway, I would never consider the panels under normal conditions, however due to my very particular situation I am paying only about 20% of their actual cost if I were to go with the cheap panels and maybe 35% if I elect the Sun Powers. Now after looking at a NET price tag of a bit less than $4000 TOTAL for a 6.23 KW system, I think that is an easy choice for me to make. My initial purchase for the first array was another very good deal though not quite this good, but thru a very different set of bizarre business circumstances that are different in this new home. Oh, and no borrowed money for this home. No loan payments. Another incorrect assumption.

If I had to pay full cost or even 50% of actual cost for solar, I would not consider it. I think the return is far too low for the outlay for that kind of money up front. With that being said, that is also the reason that I am not wanting a separate 12V system and batteries in my new home. With that option, I don't have access to cheap materials and labor, I would have to pay the full amount. Therefore the economics are not comparable whatsoever, another assumption of yours.

I am approaching this from an economical point of view and nothing else. Again, back to my initial post I was TRYING to ascertain what the economic difference was between the cheaper panels the ones I mentioned earlier and the Sun Powers. Something that I have said three times now. Have a good one.

To address the original question: Are SunPower modules worth the extra $?

Short answer:

No, not if you have enough roof space for the more economical (do NOT read as "Economy" or "Cheap", they have a negative connotation with me that is not warranted regarding the quality of the brand names mentioned) solar modules. If roof space is at a premium, then consider SunPower, but consider them carefully since they come at premium $, and cost-effectiveness suffers.

Long answer:

All the brands you mentioned are what are considered Tier 1 solar modules. The companies are reputable, and have a good chance of staying in the solar game. There is no difference in durability of the different options you have available, no significant difference in the yearly degradation in power output year after year like you seem to think is the case.Across the board we assume 0.5-1% performance decrease each year from a solar module (this is conservative, there are a lot of examples [a lot are anecdotal though] of solar modules producing the same amount of power after 20+yrs as they did when first installed). So don't assume the SunPower modules are superior just because they are more efficient. That is only one measure of quality. Maybe you have been given some more information by your installers on why Sunpower is superior. I know Sunpower has one heck of a marketing machine behind them. Please share what makes you say that SunPower is superior, as beauty is in the eye of the beholder.

As a PV designer and installer, I would feel no more/less confident with SunPower, Conergy, REC, or other Tier 1 solar modules on my roof in terms of their power output, or physical durability. I have my own preferences based on manufacturing location (US over China), and the company's business practices, etc, but that's not what is being discussed here.

Consumers often are focused on the term "efficiency", especially in a forum such as this. It makes complete sense when talking about something that consumes energy. But when talking about something that produces energy, you have to think about it a bit differently. If you have a dish washer that is half as efficient, but at 1/4 the cost, you cannot simply buy two of them and be just as efficient at 1/2 the cost. But you can do the equivalent with solar modules, you can 2x solar modules at a much lower cost that produces the same amount of energy.(Might not be the best analogy, apologies) It all depends on what you mean by efficiency, and how relevant that definition is to the situation.

I typically design with cost-efficiency in mind (most kWh produced over the systems life for a given $ spent) with options from the client on US made materials, aesthetic finishes, and other items that the client needs to choose that are not my call to make. (Black framed/ US made solar panels will cost more than clear framed/Chinese modules, but they will produce almost the same amount of energy if they have the same nameplate rating) We only offer what we consider to be Tier 1 Solar modules and inverters, so long term production is typically not a variable in our designs, as we have equal confidence in the options we offer.

The cases where going to a SunPower module makes sense is when you have limited roof space to meet the clients energy needs/wants. Going to a ground mounted array with less expensive solar modules is one option, but it almost always costs significantly more to go to the ground. So choosing a higher efficiency solar module for the roof maximizes the energy from the most cost-effective mounting location.There are a lot of variables to consider though.

I'm rambling now, so i will stop there, and let others contribute

georgec:

Maybe you should start a new thread on your idea in the Solar and Wind power section about your mini off-grid DC concept for solar. I have plenty of comments on your post but do not want to de-rail this thread.

beetle55-

I think that I mentioned to you previously that I have been monitoring the output of three solar PV systems here in the same town in the Colorado mountains, including SunPower, Sharp, and REC systems. Normalizing the measured output power by the rated power, and correcting for the different orientation for the REC system, I see little difference between the systems. Details are shown in Figs. 6-17 at http://www.residentialenergylaboratory.com/comparison_of_pv_systems.html. I see no difference in degradation rates, but do not have data over a long enough period to evaluate that.

I would agree with SolarOH that the SunPower has the advantage of higher efficiency, but that is unimportant unless roof space is limited for the size system you are interested in. If space is not limited, then I would look at rated power/installed cost.

My sincere gratitude to Lee and OH for getting the thread BACK ON TOPIC and of course for being so polite and detailed regarding this subject that the thread is about.....)) Yes, I am coming to the same conclusion here OH, as my roof space is just barely large enough to get the size system that I want in the less expensive panels. When I boil it down to hard numbers, what I am looking at is dollar per watt generated versus dollars spent getting the total production. Since my roof is big enough, I can buy several more Tier 1 panels, for a WHOLE lot less dough and get the same power production.

I was on track with that before I even started the thread, but what I wasn't clear on was the LONG TERM power production, but what I am hearing here fro you guys and a few other guys I talked to here in town has convinced me enough that the differences are just to small to justify that big price tag. And lastly these panels will be hard to see from most vantage points, so the looks of them are not important for what that is worth.

In closing, thanks so much for the input Lee and OH, I do appreciate it. I just hope ole Georgec doesn't flipping sent me another degrading and un-needed private message or get back on this forum thread and de-rail it again.......)))))