Solar Panel Cost & Savings Calculator

Calculates SCE Homeowners' Costs with & without Solar

How It Works

  • Results will appear on this page immediately.
  • Calculates solar panel cost and savings from 1 mo. to 40 yr.
  • No personal or contact information required.​
  • Accounts for all important solar, utility, & finance factors
  • Uses a system size for $0 bills, verified by PV Watts(1)
  • The only solar calculator that's accurate for SCE customers​
If you don't know your average SCE bill and total electric usage for the last 12 months, see Your Average Bill & Yearly Usage to see how to find this information on SCE's website.​​

Your Decision Choices

  1. ​Either don't bother with solar; you won't save enough.
  2. Or solar might be worthwhile, even if your bill is small.​​

How Much Do Solar Panels Save You?

If done right, solar can save an average SCE homeowner about $1,740 per year or $72,000 in 40 years. Not hay!

​Enter your bill and/or usage in the boxes to the right and you'll see the table of costs and savings for yourself immediately.

​​How to Adjust Results for Shading

There is only one aspect of your house likely to change the table's results by much: shading. All other factors are listed below under Assumptions, but they make surprisingly little difference in the size system you need (unless your house is very unusual), and therefore your solar panels costs and savings.

You can adjust the results in the table easily to approximate your shading. A very safe adjustment for shade is, for each 1% of annual shading, add about $70 to your 20-year cost of solar panels (and subtract that same $70 from your 20-year savings). You won't know your exact annual shading % until you get a shading study. But you can estimate how much shade your solar would get from these shading definitions from Solar Power World: (2)
  • ​8% shading is light: $560 more 20-yr. costs
  • 19% shading is moderate: $1,330 more 20-yr. costs
  • 25% shading is severe: $1,750 more 20-yr. costs

Modify Your Entries for "What Ifs"

  • Electric cars
            -  Add 250 kWh per 1,000 miles for charging (3)
​             -  E.g., 3,000 kWh for 12,000 miles/year
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Enter Your SCE Bills (& Optionally Usage)

(Updated 9/22/17: latest solar prices, loan-interest rates, SCE rates & NEM-2.)

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​Next Step

Call or email a trustworthy, independent solar expert for
free advice and answers to your questions. Not selling anything.​
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                      About the Calculator
​
The Solar Consumer Advisor has investigated many solar websites & other solar information available to the public (please see Solar Websites Classified & Reviewed) & has tested their estimators and calculators thoroughly. So have other experts and academic investigators (e.g., "Solar Source," a Princeton study of many such estimators, including Google's Project Sunroof.)

None of them turned out to be very accurate, and many were way off. This is partly because they do not take nearly all factors into account in their calculations, and probably can't, since they try to be applicable to everyone.

​​No other calculator that we've found analyzes and projects actual solar production and consumption of electricity by the hour throughout the year and optimizes system size to produce almost exactly $0 SCE bills.

As a result, this Solar Panel Cost & Savings Calculator, based on these models, gives the most accurate estimates online of the true, bottom-line costs & savings of PV systems for SCE customers. It is fully up to date with NEM-2, NBCs, and the latest TOU rates.

Assumptions for Calculations of Solar Panel Cost & Savings
Constants Your House
  • No shade. To adjust for shade, see paragraph above.
  • Azimuth (facing): somewhat southerly (160 to 210 degrees)
  • Roof/Array pitch/tilt: between 10 and 24 degrees (10)
  • Weather: southern California (11)
  • No tile roof, new roof, elec. panel, engineering/structural work
  • No unusual wiring requirements, building conditions, or location
Your Solar Panels & PV System
  • Excellent quality
  • Minimum size needed to zero out your SCE electric bills in first year + 10% cushion
  • System kept reasonably clean
  • Power degradation over its life is minimal
  • Cost of solar panels & system: average for system size & quality
  • Purchased, rather than leased or PPA
Form of Payment Your Present SCE Bills
  • Schedule D (regular residential rates)
  • Baseline Region #9 (other 4 Baseline Regions differ only a tiny bit)
  • California Climate Credits: $62 per year, offsets min. monthly charges (14)
  • (See SCE Website to find your monthly average bill or annual usage)

                                    
1. By using the PV Watts energy calculator from NREL, along with proprietary algorithms, to calculate the minimum system size needed to zero out your SCE bills.
2. "Four Steps to Optimize Solar Performance in Shaded Conditions," Solar Power World, 4/11/2016.
3. "Volkswagen e-Golf: real-world range vs. EPA estimates over six-month test," Green Car Reports, 4/28/2016.
4. "Energy Savings at Home," Energy Star, U. S. Department of Energy.
5. Jonathan Cook, Ph.D., "The Future of Electricity Prices in California: U.C. Davis, December 2013.
6. “Historical Inflation Rates: 1914-2016”
7. Federal Income Tax Tables,” IRS form i1040tt
8. California Tax Rate Schedules, p. 80.
9. Investment Tax Credit (ITC) - IRS form 5695 (Residential Energy Credits) and its instructions
10. "Estimate Your Roofing Costs," roof pitch expressed in degrees, RoofingCalc.com
11. Graph of Los Angeles weather: highs, lows, averages; normal and records.
12. See, for example, the HELOC at PenFed Credit Union
​13. Interest deductible from Federal Income Tax and California Income Tax.
14. California Climate Credits, California Public Utilities Commission