Charles said:
Looking into solar cells for the house, but so far, hard to pin down true cost / payback. Anyone else had luck with photovoltaics?
You've read these threads, right?
http://early-retirement.org/forums/index.php?topic=975.msg13342#msg13342
http://early-retirement.org/forums/index.php?topic=3560.msg60544#msg60544
http://early-retirement.org/forums/index.php?topic=4156.msg70916#msg70916
http://s11.photobucket.com/albums/a191/Nords_Nords/Solar photovoltaic array/
Last January we expanded our 1100-watt "starter system" to 3000 watts. Now that the winter rains have ended, I think we're finally going to have our first 350-KWHr month.
http://s11.photobucket.com/albums/a191/Nords_Nords/Solar photovoltaic array expansion/
I have a somewhat overly-complicated spreadsheet comparing the payback to just investing the costs in a mutual fund paying 6% after-tax. I manually enter the tax credits as well. The rosiest projected payback is about eight years. For someone paying retail prices for new equipment (especially at today's higher $$/watt panels) it's probably closer to 15-20 years. However that payback still exceeds the dividend rate of most equities, and my spreadsheet doesn't do a good job of assessing the effects of inflation.
scrinch said:
I've bought all the components for a solar water system, so now I just need to find the time to put it together and install it.
There are three things I wish I'd done differently in our solar water system:
1. When the pump is off, the reverse natural circulation flowrate is astounding. The return leg from the panels to the tank (the hot water) needs a reverse-flow preventer like a check valve (which I'm not convinced yet will seat tightly) or a temperature-sensitive float ball check valve ($$). The alternative is having your pump cycle all night for 30 seconds every 20 minutes to pump down the backflowing hot leg. Admittedly that's not a mechanical/electrical issue but I'm getting complaints from the bedroom adjacent to the pump flow noise.
2. A DC pump with its own foot-square PV panel. I've been told that DC pumps have brush issues that make them much less reliable than AC pumps. However our AC pump won't be much help if the hurricane trashes the power grid. I bet the DC pump brush issues aren't as bad as originally presented, and I never took the time to check into them more closely.
3. We overbuilt our system with two 4'x8' panels supplying an 80-gallon tank. We used plenty of isolation valves to be able to take either panel off-service for days when the tank would exceed 160 degrees. Now that the summer sun is shining I'll have to shut down one of the panels, and I wish I'd added a couple extra valves on the panels to make it easier to drain them.
BTW I strongly recommend using a thermal-limiting (mixing) valve on the hot-water supply to the house. Ours is set at 140 degrees but they can be dialed in to as low as 120 degrees.
It takes a long time to adjust a lifetime of water-user's habits. I still cringe when I turn on the kitchen sink hot-water faucet just to rinse out a pot, but hot water does the job more quickly than cold so free hot water costs less. I even fill the coffeemaker with hot water. I guess a truly hedonistic gearhead would connect his car-washing hose to the hot-water supply. Spouse kids me that we should have the toilets flush hot water. At least I think she's kidding!
Charles said:
For those installing photovolaics, how did you find a good vendor?
Some utility companies will only work with authorized contractors for net-metering systems. See if they have a list.
If your utility doesn't have a list (or if you're going totally off the grid) then look for a local solar-industry advocacy group that lobbies the county/state govts. The contractor we used had a great rep with the group.
An installer can only control his costs by using cheaper materials or by working more efficiently, so ask the contractor what specialized tools & installation training they use to make the labor go faster. (Component availability is very tight and prices have gone through the roof.) A specialty contractor might be even better. Although the company we used is a fully-capable electrical contracting firm, they only do photovoltaics-- they don't even do solar water.
Compare your contractor choices to this guy's website:
http://www.islandenergy.net/monitoring.htm
Poundkey said:
Just curious........Has anyone changed their incandescent bulbs for fluorescent bulbs? If so, what did you look for in a fluorescent bulb? I see several different types on the shelf. Any feedback on savings using the fluorescent?
We've been using *** for about 10 years and I've only had to replace one. Now we have a drawer full of useless leftover incandescent bulbs. Have you ever seen the commercial where two 10-year-olds are joking around and one kid asks the other "How many grownups does it take to change a lightbulb?" The punchline is "Why would anyone have to change a lightbulb?!?"
We use *** wherever the light is likely to be on for more than an hour a day--livingroom, kitchen, diningroom, familyroom, bedroom nightstands, all hallways. We haven't replaced the globes over our bathroom sinks since those bulbs are still pretty expensive. We look for the smallest bulb that'll fit the fixture. Sometimes we raise the equivalent lumen output but usually it's the same.
*** really cut down the heat too. Our house is much cooler without all the incandescent lights heating up the fixtures, especially in the bathroom ceilings.
We look for cheap because we've been unable to distinguish any difference in quality. This is especially true for hallway lights or any lightswitch operated by a teenager.