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Solar Calculators

picture of solar-powered calculator from 1973

A number of online calculators have been developed to help you make a decision about going solar. Some of the calculators are required to participate in the various California rebate programs.

These calculators provide estimates of costs, paybacks, and electricity production for solar systems and may not be a true reflection of the costs or the pay-back period for your new solar electricity system. Please note that results may vary between calculators due to differing internal assumptions and calculation methodologies. Not all of them will agree with each other, and some may use generalized assumptions.

GoSolar logo CSI Expected Performance Based Buydown Calculator
(EPBB Calculator) - calculates expected performance of solar projects and establishes CSI design factor for use in CSI rebate applications
CEC seal

Flexible Installation Calculator (for New Solar Homes Partnership) - - supports NSHP reservation applications and payment claims submitted under NSHP Guidebook, Tenth Edition through estimates of system performance. Use of this calculator is required for all projects reserved after March 8, 2017 including all 2016 Building Energy Efficiency Standards projects. Previously reserved projects can elect to adhere to the NSHP Guidebook, Tenth Edition and use this calculator

CECPV Calculator (for New Solar Homes Partnership) - calculates estimated performance and supports NSHP rebate application for NSHP Guidebook, Ninth Edition and earlier

GoSolar logo CSI-Thermal Calculator - calculates solar thermal system performance for use in CSI-Thermal rebate application process
SAVE, Solar Advantage Value Estimator Solar Advantage Value Estimator (SAVE) - estimates the present value of a solar photovoltaic (PV) system; providing a method to calculate the energy savings value of a solar system including the estimated value in annual energy savings. The California Energy Commission developed SAVE in response to expressed interest from real estate professionals, and other stakeholders.
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PV Watts logo PV Watts Calculator from National Renewable Energy Laboratory - determines the energy production and cost savings of grid-connected photovoltaic (PV) energy systems throughout the world
NREL logo Solar Advisor Model (SAM) from NREL - comprehensive solar economic decision analysis tool. SAM makes performance predictions for grid-connected solar, small wind, and geothermal power systems and economic estimates for distributed energy and central generation projects
Berkeley Calculator logo California Energy Performance Benchmarking for Commercial Buildings
DOE EERE logo List of Decision-Making Tools from the U.S. Department of Energy - a variety of calculators related to making a decision to purchase a renewable energy system
Energysage logo EnergySage Solar Calculator - Calculates potential costs and savings from solar PV across financing options for all property types.