Methodology & Data Sources
We believe trust comes from transparency. This page explains exactly where our data comes from, how often it's refreshed, and how we verify accuracy before publishing.
Last reviewed:
Data Source Hierarchy
We prioritize data sources by authority level. Higher-tier sources always override lower-tier sources when there's a conflict. For example, if Rewiring America shows a federal credit as active but the IRS guidance says it's expired, we use the IRS determination.
IRS / U.S. Treasury
Primary authority for all federal tax credit claims. We use official IRS guidance, Treasury fact sheets, and enacted legislation to determine credit eligibility and amounts.
Rewiring America API
Comprehensive database of federal, state, utility, and local incentive programs. Our calculator queries their API in real time to return programs matching the user's location and upgrade type.
OpenEI (U.S. DOE)
U.S. Department of Energy utility rate database. We use this to show average residential electricity rates by state and utility territory.
EnergySage
Solar marketplace providing real installation cost data, installer ratings, and city-level pricing. Used for average solar costs and installer listings on city pages.
Zippopotam.us
Free ZIP code resolution API used to determine the user's city, state, and county from their ZIP code input.
Current Federal Program Status
The following federal programs are tracked in our data layer. Status is determined by IRS guidance and enacted legislation, not third-party databases.
Residential Clean Energy Credit (Section 25D)
Previously provided a 30% tax credit for solar panels, battery storage, geothermal heat pumps, and other residential clean energy installations.
Energy Efficient Home Improvement Credit (Section 25C)
Previously provided up to $3,200/year for energy-efficient home improvements including heat pumps, insulation, windows, doors, and energy audits.
Alternative Fuel Vehicle Refueling Property Credit (Section 30C)
Previously provided up to 30% of costs (max $1,000 residential) for EV charger installations in eligible census tracts.
Home Energy Rebates (HEEHRA / HOMES)
The DOE Home Energy Rebates program includes two components: the HOMES rebate (whole-home energy savings) and the HEAR rebate (high-efficiency electric home appliances). Funding was allocated to states and territories, and status varies.
Editorial Standards
No Unverified Federal Claims
We never claim a federal credit is active unless we can cite current IRS guidance or enacted law. If a program's status is ambiguous, we label it 'watchlist' rather than 'active'.
Source Attribution
Every data point shown on the site is traceable to one of our data sources. We display source badges (IRS, DOE, Rewiring America, EnergySage) on all pages.
Freshness Indicators
All pages display a 'last verified' date. State and city pages use ISR (7-day revalidation). Program data from Rewiring America is fetched in real time.
Estimates, Not Guarantees
All savings figures are estimates based on available data. We display disclaimers on every page and encourage users to verify with their tax professional.
How We Verify Data
Step 1: Primary source check. When legislation changes (e.g., the One Big Beautiful Bill Act of 2025), we go directly to the enrolled bill text and IRS guidance to determine the impact on each tracked program.
Step 2: Cross-reference APIs. We compare our determination against Rewiring America's API output. If there's a discrepancy, the higher-tier source (IRS/legislation) takes precedence and we note the override.
Step 3: Update data layer. Changes are reflected in our federal programs data layer with a new verification date and source URL. All pages that reference the affected program automatically reflect the new status.
Step 4: Publish changelog. We record the change on our Updates page so users can see what changed and when.
Found an Error?
If you spot incorrect data on our site, please let us know. We take accuracy seriously and will investigate within 24 hours.