The US Federal Solar Tax Credit: A Homeowner's Complete Guide
Genultimus Research Team
Genultimus
The United States federal Investment Tax Credit (ITC) is one of the most powerful financial incentives for residential solar in the world. Established under the Energy Policy Act of 2005 and extended multiple times by Congress, the ITC allows homeowners to deduct a percentage of their solar installation costs directly from their federal income taxes.
What Is the ITC?
As of 2018, the ITC covers 30% of the total cost of a residential solar photovoltaic (PV) system, including equipment, labour, and permitting fees. According to the U.S. Department of Energy's Lawrence Berkeley National Laboratory, the average residential solar installation in the United States cost approximately $3.70 per watt in 2017, meaning a typical 6 kW system cost around $22,200 — and the ITC would reduce that tax liability by $6,660.
The credit applies to:
- Solar PV panels and racking equipment
- Inverters and balance-of-system components
- Wiring and electrical work
- Installation labour
- Sales taxes on eligible equipment
Who Qualifies?
To claim the ITC, you must:
- **Own the system** — Leased systems do not qualify; you must purchase the system outright or through a solar loan
- **Own the home** — The system must be installed at your primary or secondary U.S. residence
- **Have sufficient tax liability** — The credit offsets what you owe in federal income taxes; unused credit can be carried forward to future tax years
The ITC Step-Down Schedule
Congress set a phased reduction schedule for the residential ITC:
- 2018: 30% credit
- 2019: 30% credit
- 2020: 26% credit
- 2021: 22% credit
- 2022 onward: 0% for residential (10% for commercial)
This schedule created strong urgency for homeowners to act before the credit began declining.
Real-World Impact
The Solar Energy Industries Association (SEIA) reported that the U.S. installed 10.6 GW of solar capacity in 2017 — enough to power approximately 1.8 million American homes. The residential sector accounted for roughly 2.0 GW of that total. The ITC has been credited as the single largest driver of U.S. solar adoption since its introduction.
"The ITC has been the most important policy driver for U.S. solar growth over the past decade." — Solar Energy Industries Association, 2018
State Incentives Stack on Top
Many states offer additional incentives that combine with the federal ITC:
- California: Net Energy Metering (NEM) 2.0 allows retail-rate credit for exported solar power
- New York: 25% state tax credit (up to $5,000) on top of the federal ITC
- Massachusetts: SMART programme pays a fixed rate per kWh generated for 10 years
Combining federal and state incentives, some homeowners effectively reduce their net system cost by 40–50%.
