Our solar ROI calculator uses state-specific data to estimate your solar panel savings. We multiply your system size (in kW) by your state's average peak sun hours and a system efficiency factor of 80% (accounting for inverter losses, wiring, soiling, and shading) to determine annual energy production. Savings are calculated by multiplying production by your local electricity rate, with adjustments for annual panel degradation (default 0.5% per year, the industry standard) and projected electricity rate increases (default 2.5%, based on EIA historical averages). The payback period is your net system cost divided by first-year savings. For loan financing, we calculate monthly payments using standard amortization and find the crossover point where cumulative savings exceed cumulative payments.
EV charging costs are based on EPA-rated energy consumption data (kWh per 100 miles) from fueleconomy.gov for each vehicle model. We multiply your annual miles by the vehicle's efficiency rating to determine total kWh needed, then apply your home electricity rate and any public charging costs based on your charging mix. For gasoline comparison, we divide your annual miles by the comparison vehicle's MPG and multiply by the gas price per gallon.
The federal Residential Clean Energy Credit (commonly called the solar ITC), which provided a 30% tax credit on solar installation costs, expired on December 31, 2025. The Clean Vehicle Tax Credit, which provided up to $7,500 for qualifying electric vehicle purchases, was terminated on September 30, 2025. Unlike many online calculators that still show these credits as available, our tool reflects the current 2026 tax landscape. Some states still offer their own solar and EV incentives. We recommend checking the Database of State Incentives for Renewables & Efficiency (DSIRE) for current programs in your state.
How much solar do I need to charge my EV at home?
A typical EV driven 12,000 miles per year needs about 3,000 to 4,000 kWh annually for charging. A 3 to 5 kW solar system can usually cover this in states with good sun exposure (4+ peak sun hours per day). The exact amount depends on your EV's efficiency, driving habits, and your state's solar irradiance. Use our calculator above to get a personalized estimate.
Is solar still worth it without the federal tax credit in 2026?
Yes, for most homeowners in states with moderate to high electricity rates (above 15 cents per kWh) and decent sun exposure. Without the 30% ITC, payback periods are longer, typically 7 to 12 years instead of 5 to 8, but solar panels last 25 or more years and electricity rates keep rising at roughly 2 to 3% per year. States like California, Connecticut, and Massachusetts still see strong returns. Some states also offer their own incentives that can help offset costs.
How much does it cost to charge an EV with solar panels?
If your solar system produces enough energy to cover your EV charging needs, the marginal cost of charging is essentially zero after the solar system pays for itself. Before payback, the effective cost is the solar system cost spread over its production, typically 4 to 8 cents per kWh, much less than grid electricity in most states.
What is the payback period for solar panels in 2026?
Without the federal tax credit, solar payback periods in 2026 typically range from 7 to 15 years depending on your state electricity rate, sun exposure, system size, and installation cost. States with high electricity rates like California, Connecticut, and Massachusetts see faster payback (7 to 9 years), while low-rate states may take 12 to 15 years.
Does having an EV make solar panels pay for themselves faster?
Yes. When you charge your EV with solar energy instead of grid electricity, every kWh of solar production displaces a higher-cost grid kWh. This effectively increases the value of your solar system and can reduce the payback period by 1 to 3 years depending on how much you drive and your local electricity rate.
What EV is the most efficient to charge with solar?
The most energy-efficient EVs include the Hyundai Ioniq 6 (23 kWh per 100 miles), Tesla Model 3 (25 kWh per 100 miles), and BMW i4 eDrive35 (25 kWh per 100 miles). More efficient EVs need less solar energy to charge, meaning a smaller (and cheaper) solar system can fully cover your driving needs.
How do electricity rates affect solar and EV savings?
Electricity rates directly determine your savings. Higher rates mean each kWh your solar panels produce saves you more money. States like California (34.71 cents/kWh) and Connecticut (32.60 cents/kWh) see much higher solar savings than states like Idaho (10.58 cents/kWh). The same applies to EV charging: higher grid rates make solar-powered charging even more valuable compared to grid charging.
Can I charge my EV entirely from solar panels?
It depends on your solar system size and driving habits. A typical EV driven 12,000 miles per year needs 3,000 to 4,000 kWh. A 6 kW system in a sunny state produces 7,000 to 8,000 kWh per year, more than enough. However, timing matters since you may need to charge at night when solar is not producing. Net metering (where available) or a home battery system helps bridge that gap by crediting daytime production against nighttime usage.