Thinking about solar for home...

Additional questions you should be asking: Does the system come with monitoring? Is there a performance guarantee? How long is the lease? Will they replace the inverter during the lease period? What would it cost me to purchase the system instead of leasing?

We have a 4.94 kW DC leased system from Sungevity that we're pretty happy with. It's about $100 a month as well, and our system was designed to provide about 60% of our electrical needs, too. We've gotten 2 bills from the power company so far: $13 each time, and those are the minimum meter charges that we are charged no matter what we generate or consume. Because of the way net energy metering works, we currently have a credit of $43 toward future energy usage. Sungevity estimated our annual electric bill to be around $280 a month. With the system, it should drop to about $110 per month annually, meaning a net savings of about $70 a month on an annual basis. This means we're cash positive from day one.

If you have a south facing roof with no obstructions, then there's little reason not to do this.

 

I would do the math to see what it would cost to finance a loan to do the same thing. Especially if you can get a PACE loan.

 

Most people are typically better off owning thier systems. PV has NEVER been cheaper, so with tax credits and utility incentives pays offs can be pretty quick. I would certainly get quotes from other venders, and to be perfectly hones, I would pose the questions here:


Solar Electric Power Discussion Forum by Northern Arizona Wind & Sun - The Front Page

Some pretty sharp folks,,and nobody is selling anything, so if you post your options and prices folks can give you a pretty good opinion and why.

Icarus

 

Right, Around here people can save more money off their electric bill than they are spending on a monthly payment of a loan to purchase. It 'pays off' in the first month. We have high electric rates, but not great solar, so do the calculations for your own area.

 

I would have loved to have done a PACE loan, or paid cash for my system, but that option wasn't available, so we went the lease route. The system would have cost around $30,000. Had we been able to pay cash for it, our eventual out of pocket cost would've been around $20,000. The total amount of lease payments we'll make over the course of the 15-year lease comes to about $23,500 or so. If we factor in an inverter replacement in year 11, which can easily cost $3000, then the difference is pretty much a wash. However, at the end of 15 years we don't own the system, but they'll come take it down for free, extend the lease, or let us buy it for fair market value (whatever that might be in 15 years).

 

Friend put in solar this year when he had his roof replace, which made the solar instalation less expensive. I wouldn't want anything up there if the roof isn't sound. I know the way they write the loans here, the interest is tax deductible.

 

Getting 60% of your home energy from solar. Nice move.

Interesting that you just break even yet you are saving overall economy a lot of money directly and indirectly. There should be government incentive to do it. Germany put in incentives for home and industry and used it to increase solar energy supplied and to build up its solar energy industry.

 

We had to completely reroof our house before putting the solar PV system on. New plywood, vents, gutters, etc. They estimated we had about 3 years of life left on the side that was getting the solar, and 5 years on the other side. We bought the house 13 years ago, and the age of the roof was unknown at the time, but thought to be at least 5 or 10 years old. It never leaked on us, but the gutters had rousted out on us about 4 years ago. So it was definitely time to do so, solar or no solar.

The original design of the solar PV system was only going to be 2.47 kW DC. But when we had the roof redone, we replaced a couple of bathroom/kitchen vents with low-profile ones. As a result, the solar company was able to double the size of the system since they could rack right over them.

 

I have ridge vents, and live further south than you by a chunk but my ridge line is almost N/S so the roof facings are more E/W.

I'm thinking when I go solar I'll do somthing like the stand on the right in the picture below to tilt the panels towards the south from the eastern side of the roof. Unlike the pictured roof I have asphalt shingles and my lot has some trees that are much taller than the house but the roof is big enough to have large sections that remain unshaded.

 

Monitoring is kind of a gimmicky thing in that you really don't need it. Most major manufacturers have a display screen right on the inverter(s) - unless you have micro inverters (which are a bit more costly to purchase, as well as replace, if you have more than 2 rows of panels next to each other). With a display screen, you can see what your daily / weekly / monthly / life time output is, without having to access a PC or a smart phone (one less thing for me to get obsessive over )
Again, all major manufacturers have performance guarantees whether it's output - or hardware failure. The thing is, your installer can be out of business ... long gone after your install. It happens. So you'd still have to get some one to do the swap-out if you own.
We did our install 2009. 7.1kWh AC rated. Panels rated at almost 19% (sunpower ... as well as inverters). As to the north/south panel direction thing - one thing worth noting is that the newer/higher efficiency rated panels tend to be less affected when installed in a non-ideal direction - which is good for us because our 2 roof gables we had to work with are not ideal. One face faces slightly south-east, while the other face faces slightly north west. The 2 gable halves are pitched at around 12° so we only loose around 10% of an ideal install. What with the savings of not having to pay our old $250 electric bill ... plus fuel for the plug-in ... plus the utility has to pay us for surplus, our pay back / break even point will be in only about 20 more months! wooo hooo!

 

oops double post

 

That seems unlikely since much of the loss is from geometry. With 19% efficiency you probably just care less.

 

Let's look at the numbers shall we:

Assuming a latitude of 42°N, and using Maine's Climate (since I don't have climate data for western NY), I get a solar panel is exposed to 106.5 kWh of photons per foot^2 per year when set at 12° inclination, directly East (equivalent to splitting panels between two surfaces 180° apart). The same panels turned to face true South will be exposed to 116.7 kWh of photons per foot^2 per year. The same panels raised to 42° of inclination are exposed to 136.3 kWh of photons per foot^2 per year. So in terms of raw exposure to photons with 100% absorption and 100% efficiency, the panels facing east receive 78% of the sun that ones facing true South angled to match latitude do, and 91% of the sun that a roof of similar slope (12°) but facing true South would get.

Unless the panels in question are actually more efficient when receiving photons at oblique angles, this is the best that can be done. Given that most are less efficient when receiving photons at oblique angles, actual results will be more divergent.

 

That wouldn't help, any angles that better face the sun are shading ones looking the other way. Put another way, the sun moves, if your panels don't move with it, they are best placed to face (either macroscopically or microscopically) straight at maximal light.