I'm looking for a 10kwh solar system for my home

What are your goals in getting a PV system ?

What have you done to determine the system size that best meets those goals ?

What is your annual kWh usage ?

Do you have good solar exposure ?

Have you determined how much electricity a PV system will generate per year for your possible array location and orientation(s) ? If not, get your annual usage from the POCO, download PVWatts, read the help screens a couple of times before you start, do a couple of runs and know that a 100 % off set of usage may not be the most cost effective way to go.

How many vendors have you contacted for quotes ? Whether or not that's a good long term cost effective price depends on many factors, a lot of them local. Like most any capital goods acquisition, lowest initial price has little correlation to the most cost effective choice. First off, remember: buy cheap - buy twice. You will always get what you pay for or less. Think long term and think vendor quality and integrity as much or more than panel quality. Panels are now pretty much of a commodity like water heaters, garage door openers or toasters.

Before you da anything else, you need an education, Get and read a copy of "Solar Power Your Home for Dummies". $20 or so at bookstores or Amazon. You will get the rudiments of that much needed education, probably save yourself a few bucks and possibly won't get completely shorn by the solar vendors.

Take what you may want of the above. Scrap the rest.

Welcome to the neighborhood.

Hi JPM

thanks for the info. I've been calling a few local vendor, and so far the average price they quoted me is about $2.6/watt (before 30% tax incentive).

anyway, to answer your question:
1) goal is to save money from Edison.
2) annual kwh last year was 10880
3) i have great solar exposure

right now, my concern is which solar panel i should get and which contractor i should trust for installation.

JPM,

So i did a few runs with PVWatts, and looks like a 7Kw system will yield up to 11500-11800kw a year. Is that estimate always accurate? Does that mean I only need a 7 kW system to really get 11000 kwh/year ??? If that's the case, then my quote would drop to about $18k instead of $25...

Also, does anyone have any experience with Hanwha 315watts panel with Enphase IQ7 Microinverter?

sound expensive compared to uk --4kw system usually cost around 4-5K fitted in uk and we get a FIT feed in tariff --no grant ,

as is my typing --you get paid per kw 07p per kw for 20 years payback is usually 7-8 years

It is a model and like most models it is as accurate as the inputs. If you set it up correctly with azimuth, tilt, and shadows you should get pretty decent results.

note that it will produce kWh so 11500-11800kWh a year.

If you are in Orange county, CA, with not much shade and a mostly south facing array at something like a 20 degree tilt or so, expect a well installed array using decent and commonly available panels, inverter, and wiring to produce about 1,600 to 1,700 kWh/yr. Face it north and shade it with trees and chimneys and power poles and you'll get much less.

That PVWatts output is not an estimate, at least not of annual output. It's a possible average annual output over many years based on the input. There is a difference. It is the output of a model. The model can't predict output with any more accuracy than anyone can predict the weather every day for the next 12 months. The model is a design tool for preliminary sizing of residential PV systems, not a weather prognosticator.

As I suggested, go back and read all the help screens again. All the answers to the questions you've asked are there. Look for the parts that discuss accuracy. You'll find that just like and because of the weather, the model's designers think the annual variation between the model's output and reality can be something like +/- 10 % or so, with any 30 day period being +/- up to 30% or so. Think of it as similar to the difference between climate and weather. Climate is what you expect. Weather is what you get.

I, nor can anyone else make your choices for you. Given that you don't seem to know - or knew less until yesterday - about PV sizing, and from your exhibited naivety, probably lots of other stuff (" Does that mean I only need a 7kW system to get 11,000 kwh (sic)/yr ???), I'd respectfully suggest/reiterate you educate yourself, and (only) after that, call some established electrical contractors who have been around at least 10 years and sold solar for at least five.

Then, know that - and this is important - until you are more educated, your ignorance will get you screwed. If you'd like to lower the probability of that happening, don't do anything until you fill in the gaping knowledge gaps. Buy and read the book.

As you educate yourself, you'll probably come to the conclusion that most quality solar equipment has become a commodity. That means that who installs the equipment, their professionalism, and integrity will be at least as important, if not more important than whose panel winds up on your roof.

BTW, why micros ? You just pretty much stated you don't have what's probably the only condition where micros can be justified - shade. No shade, no micros.

Take what you want of the above. Scrap the rest.

JPM,

I only started looking at solar just 2 weeks ago, so i guess I don't have much info/knowledge about it yet, thus i'm trying to ask for help here. anyway, I understand now the actual Kw vs Kwh (before I thought if my annual usage was 11kwh then i'd need a 11 Kw system).

I have an appointment to see someone and check price on a Sun Power system, and I read several other posts where you mentioned that you own a SP system right now. I'm wondering if they are working well and did you have any problem with it so far? If you don't mind sharing how much you paid for it and what is the model of the panels and inverter?

Thanks

You're welcome.

That's 11,000 kWh/yr., not 11 kWh. Like I wrote, you need an education before you go further. Buy and read the book first and before you do anything else, including contacting more vendors. Right now, your solar ignorance is your worst enemy. Then,fill in knowledge blanks here. Your questions will be less wasteful of other's time and the answers you get back will have a lot more meat on them.

If you want to spend more $$ for the same performance as other systems, by all means get Sunpower. You'll get bragging rights and not much more for the extra money you'll get screwed out of. And, FWIW, those in the know will know you're solar ignorant and easily separated from your money. Similar to a good lawyer crossexamining a witness in court, get enough knowledge to know the answer to every meaningful question you can ask a vendor before you ask it. You'll learn more about the solar procees and even more about who's B.S.ing you.

I got the S.P. system knowing it would not be cost effective but also knowing it was the only way I'd get an answer I could believe to be correct and truthful, I paid to find out the truth or B.S. of the S.P. hype. S.P. won't be straight about it and S.P. owners are clueless about what they bought, and even if informed, probably wouldn't want to admit they screwed themselves. Soi, I paid a premium for tha ability to get my own, unbiased answers.

Did you also read some of my posts in which I unequivocally write that while Sunpower is good stuff, it's no better than other quality equipment ?

Answers to your questions: My system is working well, but really no better than the other 130 or so systems in my HOA, some of which are S.P., but most are not. Once adjusted for orientation and shading, the 8 - 10 systems I monitor have just about equal annual output per installed STC. Check a source called PVOutlet.org for systems near you. You'll find that once adjusted for orientation and shade, similar sized systems of many different mfgs. tend to have vary similar output.

The price I paid to the vendor was $4.50/STC W before tax credit. That was the 2d lowest price/STC W paid up to that time (08/14/2013) for a Sunpower system, according to the CSI database. The lowest price was for a S.P. vendor who installed the system on his house. By way of comparison, other good quality non S.P. systems were running ~ $3.50 - ~ 3.75/STC W, +/- some at that time according to the CSI database - a very good source of information and a very good negotiating tool. My system is 16 ea., 327's with a rebadged 5 kW PowerOne string inverter. The running average output per prior 365 days since startup plus 1 year has been 9,135 kWh/365 running days, including/after about 4.5 % annual loss for late afternoon shading, high value, 9,593 kWh/365 running days, low value, 8,736 kWh/running 365 days, pop. std. dev. 197 kWh. If my output is a bit better than some (but only a bit), it's mostly because of the details I put into the design as well as an ~ 9" -11" clearance under the array which tends to keep things running a bit cool(er).

Take what you want of the above. Scrap the rest.

I don't think SP is at $4.50/STC before tax credit anymore, based on what the vendor told me, it's around $3.xx now. So if you were to get another PV, based on your current knowledge, which system would you choose? and at how much per STC W (before tax credit) is considered a good price?

Thanks

You're welcome.

If you believe what someone with skin in the game tells you without independent verification or your own due diligence, I have bridges for sale. But, there may be a kernel of truth in that broad brush of a price. Also, other quality systems' prices have also dropped over the last 5 years as well. Good systems can be had for something like $2.75/W +/- some. FWIW, don't be too surprised if that "xx" in your $3.00 price point for S.P. is closer to .99 than to 0.0I.

I'm quite aware of current pricing and where it's been - that's why I gave a comparison of other system prices when I purchased. I don't think the S.P. premium is still ~ 20 % as it was 5 yrs. ago, but it's probably still in the 10 % to 20 % range.

One thing that's slipping through the cracks here: In life, everything is negotiable. Everything. The going price/W for S.P. per the CSI database when I purchased was a bit above $5.00/W. I paid $4.50/W using negotiating techniques and foreknowledge (homework) that's commonly available. My neighbors ave. for S.P back then was about $5.25/W. That things are negotiable is at least partially confirmed by a look at how prices/W for S.P. (and other systems) are all over the board on the CSI database, and even in the same neighborhoods like mine. As the guy on my HOA who reviews and recommends PV systems to the rest or the Arch. Rev. Comm. and anecdotally, I know every system around here almost intimately, including what everyone paid. It's sometimes embarrassing to see close neighbors pay much different prices/W for what are essentially identical systems purchased a month or two apart from the same vendor (part of that due to the me too - keeping up with the Jones' thing). Some folks are good negotiators, most are clueless that everything is negotiable, and then lie to their neighbors about what they paid. The vendors spot the ignorance and act pretty much as you'd guess. It's just business.

Since you ask, for my situation, The short answer to your question is I'd choose the best system I could afford that was sized and designed to produce the lowest long term LCOE mix of POCO and PV power that was still below the LCOE of POCO power alone.

If you are looking for someone to tell you what to buy, you'll need to look elsewhere.

If you're still reading/interested, since every situation is different, as are some reasons for acquiring PV, two scenarios for me, both of which reflect my current situation and based on my knowledge and a dart throw or two about the future and my best overall information as I think I see it:

1.) If I didn't have a truth bone to pick with S.P and was only concerned about getting the most long term bang for my buck: I'd start with the assumption that, at some time in the future, I'll be on T.O.U. rates/tariff. For me, that means that I can use the idea that I, or anyone in SDG & E territory on NEM can estimate how much revenue an installed kW of PV can generate as an offset of my electric bill, at least under current PV NEM tariff. Then, size/design a PV system using commonly available models and see what the tradeoff of various system sizes might be in revenue (not necessarily energy generation) vs. do I want a smaller system and only draw power from the POCO at super off peak times and tolerate such inconveniences as such a lifestyle may entail, or pay for a larger system as would perhaps be necessitated by more random time use of POCO power (Study up on T.O.U. and how it works).

And all that within the overriding constraint of keeping the PV/POCO mix cost/kWh below the LCOE for POCO power alone. Still with me ?

If I did all that and found some measure of PV to be in some way cost effective - and keep in mind that all this, in the end, still needs to also have a better return on investment than other places I could put/invest the $$ over the next 10 years (like socks/bonds/real estate/pick something/mix of investments) with and after some consideration of risk - I'd size a system iteratively until I got a system size that, between POCO power and PV power, and my always less than crystal ball perfect assumptions about the future, gave me the lowest amount of what are NPV, LOCE dollars out of my pocket to meet my goal of electric service to my dwelling over the next 10 years. By then, I expect I'll have moved on and/or be demented and playing fungo with my poop in the happy land of the terminally bewildered.

Notice I haven't contacted any vendors yet ? That's back to the idea of being informed on my own and getting answers to my questions before I ask them of vendors or those with skin in the game, mostly because I don't like being lied to. So, before contacting any vendors, I'd then see what was available and the likely best choice(s) for my equipment. Then, I'd see who handled such equipment. Then, I'd narrow the choice to a couple of vendors for each mfg. of panel who were also long established electrical contractors and who have sold/installed PV for at least 5 years and hopefully longer - they seem to be the type with the most knowledge of how to do home improvements and also know the value of a customer and the fragility of a reputation.

Since I'd already know what size system I want and what I can pay from all my prior sizing/economic work. I'd give all chosen vendors a request for proposal that includes everything I want (and a few things I can live without to use as throwaways in negotiations), but no hint of what I'm willing to pay at this stage. I'd then ask for their best price and expect to hear back from maybe a third of them. For those who respond, I NEVER share prices among vendors as I know that's a fool's errand. One of my main tools in what's now a negotiation is the other side's lack of certainty about where they need to be on price. I know "price matching" is exactly what vendors your to learn where they need to be. It's a B.S. con. Every peddler's dream is to get the competition's prices. Been on that side in the past. Reveal or share pricing between vendors and you just locked in any chance of getting a lower price.

I negotiate tough but fairly and respectfully, keeping in mind the goal is the most bang for my long term buck and not simply lowest initial price - another fool's goal.

2.) If I still had a truth woody for S.P., I'd do what I did the first time. It's still decent equipment and for now I've still got more $$ and time than brains, and a priority that places some value on satisfying my curiosity as to truth vs. what I see as deceptive B.S.

Take what you want of the above. Scrap the rest.

We should always check some points before buying any solar system.

Solar invertor efficiency

All invertors are not equal but normally it should have 5-10 years of warranty.

Maintenance cost:

Most of companies provide panel warranty up to 25 years. Check all the maintenance cost involved within it.

Roof Suitability:

Check your roof suitability solar panels are most effective for 30-35 degree angle.

Check Cost, efficiency, Degradation

LG has provided efficiency of 16% but normally it would be up to 21%. Some brands provide up to 21%.
Cost given to you is little bit high as it would go up to $21500.

If it fits to your requirement and suits to quality then go for it otherwise there are lots of companies to choose best solar panels.

Lvb -- who was that LG quote with? I'm getting quotes right now for a 15kw system and $2.48/watt for LG 360 panels is an awesome price.

What inverters are they using? I got quiteq $2.65/watt using Enphase iq7+ microinverters.

Anyone who can help with my needs? I need a solar panel powerful enough to power the Refrigerator, 2 Air Conditions, 4 lights and a Television.

What would be best design? Can I make the solar panel more efficient if I have a little less space than it is actually needed for the amount of panels that will be needed to power these electronics?