[MediocreButArrogant]

Originally Posted by airics

savings 65 a month… i paid a hair under a grand installed so… 65x12= 780 saved AND
i took my single speed pump and put it on craigslist and got $175 in a day.. so.. 965. in a year..

Most people don't run their pump as long in the winter as in the summer. Same is true for the cooler months of spring and fall. Less run time equals less savings. Two to three years is correct for most people.

[BBMW]

You're going way farther than I was. I was just responding to Airics' statement about wanting to run his AC off of solar. I just wanted the metrics on that. The answer seems to be that with a biggish PV system, at peak solar output, it comes close, but doesn't quite make it. Off peak the gap is greater. And, of course, at night, the PV is useless.

Originally Posted by lvoc

It is actually more complicated than all that. Los Angeles claims that incremental KWHs at peak times are worth $0.45 each. If so then adding 5KWs is worth around $2.25 an hour at peak times. So 4 hours a day at peak times you get $270 per month during the high summer. And that is on top of a smaller payment the rest of the time.

But that argument has a hole in it as well. Solar PV does not peak when energy usage does but a few hours before. So solar is down substantially when the demand peaks.

So in the southwest household solar is good for offsetting some, though not all, of the peak engineer need. And there is going to need to be a complex calculation of what that power is actually worth. I would in fact expect litigation or legislation.

Further complicating things is the homeowner commits when he opts to install PV solar. And there are a whole range of outcomes. If you jump early you may make money but a lot less than if you jump later driven by the efficiency and cost of the installation. Complicating further the tax credit drops heavily at the end of 2016 and may well not be extended with the presently hostile Congress. it could however come charging back if the Congress changes in 2016.

At this point it would appear reasonable to wait and jump in during 2016. Take advantage of both another year of progress and the tax credit. If not then you wait until 2017 if the tax credit is reinstated or perhaps 2020 or 2021 if it is not.

And you consider all the good advice from Scoop et al to drive energy usage down...which is cheaper and more cost effective than the arrays.

So not now. Maybe next year. If not another year or two...or five or six depending on how the politics and technology runs.

[lvoc]

Originally Posted by BBMW

You're going way farther than I was. I was just responding to Airics' statement about wanting to run his AC off of solar. I just wanted the metrics on that. The answer seems to be that with a biggish PV system, at peak solar output, it comes close, but doesn't quite make it. Off peak the gap is greater. And, of course, at night, the PV is useless.

Wrong model. Basically you exchange the power you generate to the utility for an equal amount. So even if your system cannot hold the required peak to support your home you can still end up with a zero power bill by supplying power to the utility at non peak times.