I want to buy a solar panel kit to run my central AC unit. it is a 3 ton unit. Can I do this? The electric rates in the Chicago area are skyrocketing and I can't keep paying 350 dollar electric bills during the spring and summer months
Solar in Chicago is not much help, you would need at least 3kwh for whatever size unit you have, (3 tons is meaningless in this context!) You would not get enough sun even in the summer to operate for more thn 6 hours a day. For Chicago you probably need a wind generator, or go for a heat pump.
It sounds like saving money is your chief goal. If your house is not already super-insulated, that should be the first target. Super-insulation, radiant barriers, double-pane windows, white roof, weatherstripping, attic fan. Number two would be conservation. Can you turn the A/C up to 80? I visited a place in Wyoming when it was 0 outside, and 80 felt very pleasant. Third, efficiency. Have you considered a ground-sourced heat pump? Deep down below your house the water table may be colder than 40 degrees F, and can provide good cooling. After all that, you can look into solar electric, which may or may not be a good deal in your area. The type of solar electric that is most cost efficient is the kind that connects right to the house wiring and works alongside the normal electric company. You can talk with a local installer and get a free financial analysis. Then you can look at it and see if the installer is on the level, or trying to play accounting tricks with unreasonable assumptions. Solar makes sense in most parts of California, but Illinois is not known as a big solar area. The kits you have have seen were probably for standalone solar, generally an expensive proposition for the amount of power you get. Put another way, either it will be low power, or it will be very expensive.
I know that in Texas we wouldn't even try to run an air-conditioner on a generator without at least a 6,000 watt generator and we would prefer a 0,000 watt generator. The calculator on the Kohler website says it'll be 7,500 watts. At $5 per watt to install a solar photovoltaic system and assuming you also need to run it through the night and taking into account that an inverter can be as bad as 60% efficient, you're talking about $87,500 just to run your AC for 25 years. The first step in going solar is to significantly reduce your energy use. You're not going to maintain your current energy use on solar, at least not cost effectively. If you did want to run an AC on solar power, you may want to look at absorption air conditioning and use evacuated tube solar thermal collectors instead but don't expect it to be cheap and it usually only augments the use of natural gas in the absorption chiller.
