Thinking of installing a 7.5kW PV system on our house. Wondering if anyone on here can shed any light on their solar system experiences? Our contractor states that taking into account our shading, roof angle, weather, useage history, etc., we should see close to a 94% reduction in our yearly electric costs. The system is going to cost about $23,000, but after federal and state tax credits are applied, will cost us about $5,000 out of pocket. I don't know how I can say no to that..... System is estimated to pay for itself in 3.3 years.

 

I looked into it and the contractors PROMISED that we could get state rebates and federal tax credits but those programs are only funded one year at a time and were SEVERAL years behind in making rebates so it was a gamble as to IF we would be paid. Contractor SWORE that we would but we refused to bite. It turned out that the program was not renewed in Florida so we would have never gotten our money if we had taken the bait. So be warned! Other BIG problems but I have to leave now so will finish reply later.

 

OK back again.

First, a little back ground: first, I'm an engineer by profession so always do the math and I know what works and what doesn't work BEFORE I dive into a project. Second, I've been fooling around with solar powered projects for over 40 years. I also took courses in solar and alternative energy as part of my engineering coursework in college and that included visits to the Florida Solar Energy Center located at Kennedy Space center and operated by the University that I attended and a LOT of discussions with their researchers. I also built and installed my own solar hot water system 30 years ago and it still provides 100% of my hot water needs. So I DO know something about solar energy!

Ok so to get back on track, the contractors that were offering the solar electric installations around here were CLUELESS about what they were doing! They do have general contractors licenses and in Florida they also had to get a special "solar contractors" license but that test is so easy that I took it with no study and passed it with 100% on my first try and I have never worked as or for a contractor.

Here's just SOME of the problems that I found and I talked to at least a dozen contractors, First, they were clueless about where ANY solar system has to be aimed! The answer should be obvious. Towards the sun! In the northern hemisphere that means SOUTH! Simple huh? Well not them them, they were just nailing solar system to people's roofs regardless of which way they pointed. The same problem with elevation. To get the maximum energy, you have to collect the maximum amount of sunlight. Which means that the collector needs to be aimed directly towards the sun. This gets tricky because the sun's elevation depends on your latitude and also the sun's elevation shifts throughout the year due to the tilt in the earth's axis so you just have to use an average value (unless you want to go the expense and headaches of tracking system). But again, it boils down to a real simple formula. For the US mainland, it's your latitude, times 0.76 and add 3.1 degrees. But again, EVERYONE of the solar contractors just wants to nail the collector to your roof regardless of the angle that it's at!!! And when I started talking to them about the optimum angle and direction, they were completely clueless. Most of them had no idea even WHY the collector needed to be pointed in a certain direction or elevation, much less how to compute it! You can go on line and in less than two minutes you can find out how much efficiency is lost due to off axis collectors. TWO off axis!

BTW the FSEC (above) is a GREAT sight to get information about anything solar. They test everything and they will give you the results so you can decide what's worth buying and what's not instead of just relying on a salesman's BS. Every solar collectors sold in Florida is required by law to be tested so the numbers are there. The FSEC is run by university (UCF) so there's no "wishful thinking" like in most manufacturer's tests!

Other problems: The panels and the inverters that they use are both made in China and like most things made in China, they don't last. As best I could find out, they're only good for about five years!!! If you go onto an electronics forum like EEVBLOG, you'll find lots of discussions about FAKE ICs and other parts coming out of China. They work, sometimes, but they don't last. A LOT of the materials used in Chinese manufacturing are of poor purity and just will not last. Remember the poison Chinese made dog food? Or the kids toys made in China and painted with lead bearing paint? Typical examples of Chinese lack of purity, testing AND quality control! Am I going to pay $25,000 for something that something that could fail COMPLETELY in a couple of years AND that has NO service information and a total lack of repair parts? HELL NO!

On top of everything else, the solar contractors just want to sell you want is really just a "starter" system based on the cut off point for the tax incentives and rebates. I don't use a lot of power but the systems they were selling here would have supplied only about 40% of my power needs AT BEST! And when I say at best, I mean that's if they pointed them to right way and at the right elevation AND they put out the claimed amount of power, etc etc.

Another thing that you need to think of is how they're going to mount it. My current how water solar collector is a single 4 x 8' panel mounted up on struts (so that I can get correct elevation and azimuth) and only has eight lag bolts bolting it down and going through the roof and into the wood roof trusses and every year I go up and clean the collector and reseal the roof bolts but when I replaced my roof last year I still found two serious rotten places and had to be fixed. Now compare that to a system with ten or twelve collector panels (a 40% power system BTW) and a dozen lag bolts in each one!

What I wanted was to built a large aluminium car port and have the collectors mounted on it so that a leak wouldn't matter but again the contractors around here use "a one size fits all" installation and are only allowed to install flat against the roof unless they get a Professional Engineer to check on wind and rain loads, dead loads, live loads, etc and sing off on it. But they don't have that kind of background or support and have no clue of how to go about it.

I could go on and on but I think you get the point. They systems that they were selling here in Florida were a joke! And worse, they could RUIN your roof. And not just the shingles or sheathing but the roof trusses as well. I had to have one of mine cut out and replaced.

 

Oldnnew,

I just looked at your location. New York state? A solar collector is NOT going to work well for you! No matter how good a system you have. You have too much snow covering the collector for a good bit of the year. Too many cloudy, gray days. Too many SHORT days in the winter. And LOW elevation of the sun will mean that it's easy for tall trees and buildings to completely shade your collector AND low elevation also means that the sun light goes through more of the atmosphere and is greatly reduced.

Location alone should kill any idea of a solar system for you IMO.

Solar CAN work well in places like Florida (me), Arizona, Texas or Southern Cali but not for you guys in the northern states.

 

You should install the system on your house if you have the cash. Realistically, it'll probably take closer to a decade to recoup the full cost of the system, but if you have the money, why would you not want clean power independent from the grid?

The drawbacks listed by Joe are mostly contractor-related, and I assume you're not purchasing the system sight unseen, so you can verify what components you are getting. The panels can be aimed, and if you pony some cash they can track the sun throughout the day. There are many homes in NY with solar panels, and the only real drawback is political. The systems are heavily subsidized.

 

anderson,

The problem with that idea is that pay back is most likely going to take FAR longer than ten years and from what I could learn the expected life of the components was far too short to last until you reached pay back. Read my post for details. I don't know what subsidies OP can get but subsidy here was $10,000 (state) plus 40% of cost (federal) IIRC and payback was still 4 to 5 years and that was for a PROPERLY installed system (which NONE here were). If OP has similar costs and similar subsidies AND lower performance due to location AND short component) life span then he will NEVER reach payback!

Short version: Don't believe what the salesman tell you! Verify expected performance with a creditable test organization and get salesman to put equipment stated performance, component life expectancy, etc in writing. AND verify that the subsidies ARE available and not paid out several years later and only funded year to year as our's were.

Yes, MAINY of the problems here were contractor related (and that includes using poor grade of Chinese made components and poorly designed installation AND them making unfounded promises about rebates) but I expect that will be the same everywhere. This is a new field and contractors can make a real mess of these because they don't know better (even though they should!) and consumer's don't know better and take salesman's claims at face value.

BTW what is YOUR experience with solar systems??? What kind of personal and/or professional experience do you have with them?

 

Assuming this works out this way for you, I'm glad for you, but outraged that tax payers are giving you $18k of tax credits for a friggin solar system.

These damn things can't pay for themselves yet from everything I've read, but might be able to pay you back if it's only costing you $5k.

 

I hear what you're saying KMAC, and agree, to a point anyway. It's not like all other energy forms aren't subsidized by government. So why not solar ? Though that rate of subsidy seems almost obscene. Did I say almost

To the original post, best advice to add to the above before going forward is get several references and check them out. The farther back the better for long term experience. Either call up the past customers or at least drive by the installation if you can. Don't take testimonials at face value. And if you can find a site they are working on currently have a good look at the work being done and see if they look professional or fly-by-night.

I agree it's going to be a challenge to make it work if your solar hours are weak and few. You might be better off looking at conservation instead if you haven't already. LED lighting, insulation upgrade, etc. depending on what can be done in your situation.