Come and get ‘em while they last! Southern California Edison (SCE) offers residential rebates of $1.55 per watt of solar panels installed, while the other two main utilities covered by the California Solar Initiative (CSI) — PG&E and SDG&E — offer a lower payment of $0.65 per watt. Fewer customers in SCE’s service area have taken advantage of the CSI solar rebates, so the step-down program still offers a higher rebate. To highlight what a great deal this makes for SCE customers, let’s walk through the cost with GetSolar’s Solar Financial Calculator.

Our fantasy house for this exercise will be  in Murrieta, CA and call the beautiful 92563 area code home. It has a Net Metered Domestic Service Electric Rate, which you can find on your monthly electric bill, along with the actual dollar amount you pay per month. Annual Bill Escalation is a trickier estimate, and for California I chose a rough estimate of 5 percent per year.

After including these basics about the home’s location and electric bill, we get to move on to information about the roof and future PV system. Let’s assume we want to install an average sized 5 kW PV system at a cost of $7,000 per kW. Now it’s likely that you would be able to install panels at a lower per kW cost, but for our purposes a conservative estimate is best. My roof also has a 30 degree tilt and one side faces south (Orientation). In real life, you would have to go outside and estimate tilt based on your actual roof, and you can use Google Maps to see its orientation. For California, ignore the REC menu items, since this type of solar incentive is not applicable in the state — at least not yet.

Next we get to see the results. A 5 kW system on a south facing roof in Southern California Edison territory gives us 10 year payback period, after which we begin to profit from the investment.

Not too shabby. The solar system saves me $1400 per year on electric bills and will pay for itself by 2020. From then on, the system will continue to generate free electricity for another 15 years or so.

As with any financial model, standard caveats apply — and changing the assumptions (where you are, your utility bill, taxable income, roof tilt, etc.) can yield drastically different results. So for those of you using this for an actual home instead of the fantasy version I tried, make sure your basic information is as accurate as possible.

The main message here is that SCE’s high rebates make for a great deal on solar. If you live or work in their service area, solar might make a very strong investment for you.