Exactly. I live on the ocean and only run the A/C in the afternoons some small number of days per year. On a typical A/C day, I probably use 30 to 40 KWh a day, meaning I typically use 10-15KWh net from the grid. But the days I don’t use A/C I’m a net producer and that adds up and more than offsets my use.
My system wouldn’t cover my needs in a more consistently hot location. And if it was my choice, I wouldn’t have installed A/C at all. I lost that battle.
Thanks. We run 3 1/2 tons of A/C at night during an Arkansas Summer.
God help you. I spent a few summers with my grandparents outside of Hot Springs and am not sure the area is survivable without 24/7 air conditioning.
This is the set up you’ll need…
I took an engineering course where we sized a house and designed a solar heater.
I drew Fargo, ND.
The idea was that you bought the solar systen on a loan and compared that to the cost of oil heat.
I designed for the load of the house, and the home owner lost money. I designed at double the load, and he lost money out the kazoo. I designed for half the load, supplemented with oil, and he made money.
Great info here. I have considered solar power a few times. I have a passive solar home way high in the Colorado mountains. Cooling is NOT and issue. 
Anywho, I’ve had two copies of thisThe Solar Living SourceBook.
It is IMHO, very good basic information, and fun to just page through. It’s sort of a Do-It-Yourself approach. But should be interesting to anyone thinking about getting away from the grid.
I wonder what that looks like with current PV + tax credit prices running a modern heat pump that supplements solar thermal.
Or even just solar PV paying for oil heat…
The OP wants to have solar power in case of outages, so this would be an unwelcome surprise.
Thus the OP - and the rest of us - might well be interested if you were to go into more detail on this.
You would think they would just take the house off the grid and let the guy have power. I wonder how difficult it is to synchronize the phase when re-connecting.
Why do you want to go “off grid”? You’re not going to all FULL SURVIVALIST on us, are you? 
I think the more important decision you need to look at is if you’re going to buy or lease the system. Lease gets you in at no (or very little) cost. Owning it gets you the best return over the lifetime (assuming no major maintenance issue pop up).
There’s not a simple way to “block” power from the grid and run solely on solar? I’m thinking is the power goes out in the middle of a sweltering day, I go into my basement and throw a switch that separates me from the grid and allows solar electricity to power my A/C. When I see that the power has been restored, I switch it back. I don’t know what I am really talking about though, and I live in coal country so (for now) my electricity is cheap…about $250/month at the height of summer heat or winter cold.
If all goes according to schedule I will be installing solar and a home battery in a couple weeks. A home battery application functions like a UPS in that all power used in the house first comes from the battery, which is charged via solar panels. Only in the event the battery is drained would I be pulling power from the grid. According to the promotional materials, the battery has enough capacity to run the house for about 3 days - without charging which wouldn’t be the case since it would charge during the day. That’s pretty close to off grid.
I live in the coastal part of SoCal. We just don’t need it here for cooling purposes. I mean, it’s a major heatwave in the southwest apparently and we’re headed to 81 here today. 81 is patio and BBQ weather, not inside with the A/C on. Low energy appliances, low energy lights, tinted windows, and keeping sunny exposures covered during that part of the day really does work. Do all that before going solar. My electricity bill runs about 50 each month, and that includes gas and electricity. Not enough to return the cost of Solar installation in my lifetime.
How expensive is the battery, and how long is it suppose to last before you have to replace it?
I had my house audited for solar a few years ago, and unfortunately it doesn’t work out so well for me. Although I live in CA, my neighborhood has a lot more trees than typical, and my house is pretty old (built in the 1890s), having an 8:12 pitch roof, broken up with gables, as opposed to the typical 4:12 pitch you see on most homes here.
The battery is $5K plus installation fees. They guarantee a certain longevity, with expected decreases in efficiency over time. I believe the warranty is 10 years.
One of the drivers is cost savings for me, but not the only one. Acting as a whole house UPS is important. Supporting a new technology is important. Being self sufficient is important. Not sure where it all ranks, but with the decrease in pricing it became viable to make those choices, for us.
What is a “whole house UPS”?
Who backs the warranty?
$5K for 120 months? That’s a little over $40 a month.
It’s just something you ask for – solar plus storage or solar with backup power – when you shop around.
I’m not the best person to talk about the wiring, but I might be able to discuss some of the basics. Is there anything in particular you’d like to know?
Basically, you do a load evaluation (what do you want to keep on, for how long?) and get an appropriately sized battery bank and an inverter and charge controller designed for hybrid grid tied and battery use. Any good salesperson would help you find the right components.
The main downside is just the added unnecessary cost. Unless the grid is really unstable where you’re at or you have essential loads , you shouldn’t need battery backup.
A battery bank sized to keep a few things on for a few hours would be cheaper than one sized to keep the whole house going for several days (as in an off grid scenario).
Not that I know of, without batteries. I presume because solar output is too unstable and most appliances wouldn’t like that, especially if they have motors. But if I’m wrong I’d be happy to be corrected.
In the tech world, a UPS is an uninterruptable power supply, basically a battery for your desktop computer. Scaled up to a whole house, solar calls it battery backup and Tesla calls it a Powerwall. Same thing. Batteries. Lead acid used to be the go to chemistry. Tesla is really shaking that up with their gigafactory and super cheap lithium ion.
I am getting the Tesla Powerwall 2.0. So the warranty is with Tesla who acquired SolarCity, the solar company.
As Reply noted, UPS is uninterruptible power supply, so if there’s an outage or a power flicker or things like that, I’d be pretty much unaffected. Currently the Powerwall is not setup to handle 220v power draws, so it wouldn’t take things on dedicated circuits like an electric clothes dryer, or the big A/C units. Everything else in the house will be fine like the refrigerator, computers, cable modem/router, and all the lights and plugs. No A/C would be a bummer, but we do already have a whole house fan which is great where I live. We aren’t a high energy user as it is, our thermostat is set to 85 on hot days, and like, 59 on cold days.
The way to think of the warranty isn’t $5K for 120 months. The hardware itself costs money. The way I think about the costs is not when I will break even, but instead more like an ROI. It is the marginal decrease in cost for the amount of investment. So if I spend $5K and I save $25/month, a break even analysis would say that’s over 16 years to recover that money. But an ROI would say I’m earning 6% return which is better than my savings account. My ROI is better than that, but not quite as good as Tesla stock over the last year.
You are a braver man than I.
You live at my house don’t you?
Sad part is i would leave it off, but houses mold at 110% humidity
Not many cold days worth counting in florida, the sun heats the house enough on its own.
