How big is your system?
How much did it cost?
What percentage of your power use does it cover?
We lived off grid for 5 years but in the summer, we’d run a generator for a window a/c unit. Two of the 5 years were heat wave years with high temps well over 100 for weeks and normal summers here can be mid to high 90s. It’s also humid here. So we were quite miserable on summer days. It wasn’t worth the effort to run a small window unit by day so we’d start it up after the sun went down behind the trees to cool things off enough to sleep.
An earth bermed house would fix a lot of the heat issue and is in our plans. Some things are just impracticable for solar/wind. Electric dryer, range, my welder, full size a/c for house. We line dry but do have an electric range, simply because it was given to us. I’d prefer gas/propane.
Those big electricity use items just don’t give you a decent ROI.
Lighting(LED), electronics, small kitchen appliances, fridge, freezer. All those are doable.
We had a puny 350 solar panel setup with 4 golf cart batteries. Ran lights, electronics and a 12vdc chest fridge the size of a big cooler. $1500 for the solar stuff and $600 for the fridge. In less than ten years, everything broke down/wore out but the panels. Fridge quit working, Xantrex C40 charge controller and china inverter quit working and Interstate batteries wore out. The Xantrex was supposed to be bulletproof.
It powers 80% of the usage in my large house. I pull a little from the grid when I have two major appliances on at the same time (i.e. central A/C and dryer) because I can get at most 8 kW of continuous DC to AC conversion. But that's only brief periods of the day. I also pull from the grid when I consume all of my 21 kWh battery storage on days when it's rained a full day after being cloudy the day before (I get nice power even on cloudy days, but not enough to fully charge the batteries to last the whole day the next day).
But I'm in the south near Huntsville, with no shade on my house, and the back of my house facing south towards the equator (more sunlight) which is also facing the woods (no neighbors to complain about solar being an eye-sore because only the squirrels and deer see the back of the house). So I'm in an ideal situation to get the most goody out of the federal ITC solar tax credit for 26% of parts and installation (they renewed it this year I think if you want to take advantage of it).
IMHO the key to finding how much you need is in part based on your inverter capability. If your inverter is worth spending good money on (it's often one of the expensive parts) then you ought to get the max # of solar panels/wattage it can process. Otherwise, it'd be like spending a lot of money for a powerful pickup truck but combining it with a small trailer and being able to haul just a little in the end. Nor would you buy an expensive trailer that can haul a lot, but a small truck to pull it. Either go small with both the inverter and panels, or go big with both the inverter and panels. Don't do big on one and not the other and expect any return on investment.
If things go like it did the first year I'll pay off the HELOC I took out to pay for it in 9 or 10 years, then the extra savings I spent on top of that in 3 to 4 years. Thus it'll pay for itself in 12 to 14 years with everything having at least a 19 year warranty (batteries), 20 year warranty (inverter), and 25 year warranty (solar panels). But that assumes an inflation cost of 2% to 3% per year (i.e. buying a kWh from the utility today costs more than a kWh a few years ago). If the Dims get their way and jack up power costs then my system will pay for itself sooner, all with me not grumbling as much as most folks.
15,000 watts two axis tracking panels
Two 8000 watt grid tried but stand alone capable inverters
300 amp auto trip transfer breaker.
Cost of panels 15 cents per watt in 10,000 watt min order. Cost of breaker panel tie in done by licenced Elc. $800 cost of labor for install panels on flat roof line with like mounts was $12hr times four guys over a two 8 hour day period. The mounts and aair trackers were above and beyond a typical residential system because this system is not classed residential its commercial on a LLC selling power to ERCOT at peak times of day at peak rates. For a residential system fixed panels at the angle equal to the latitude would be used. Or single axis flush mounted pivot trackers. Either way a residential 15,000 watt system is around $12000 all in with modern components at wholesale prices installed by professional installers.
My system has never generated less power than my huge home has used it’s a combination flat roof commercial steel building and rammed earth structure well over 5000 sqft not including the workshop , covered pool or second “mother in law” 2-1 guest quarters which has it’s own 5000 watt fixed panel system. I sell so much power each month that it zero my grid tie fee and pays me back on avg 40 cents per kWh sold peak rates in summer hit $120 a megawatt hour and $50 is common. That’s 50 cents a kWh for every solar kWh sent to the grid. My two rent homes all have panels they also sell power to the grid the tenets have separate smart meters they pay their own commercial power providers they don’t get free power.