Idaho’s main energy efficiency tax deduction, under Idaho Code 63-3022B, lets an individual homeowner subtract 100% of the cost of qualifying energy efficiency upgrades from state taxable income, with no dollar cap. There is one eligibility line that disqualifies a lot of homes before anything else matters: the residence must have existed, been under construction, or been covered by an outstanding building permit on or before January 1, 2002.1Idaho State Legislature. Idaho Code 63-3022B – Deduction for Energy Efficiency Upgrades Newer homes do not qualify, no matter what you install.
Check your home’s construction date against county records before you plan a project around the tax savings. That one fact decides whether the rest of this applies to you.
Which Homes and Owners Qualify
The deduction is for individual taxpayers only. Businesses and commercial property owners cannot claim it. The property must be the taxpayer’s primary residence, and it must meet the pre-2002 construction test described above.1Idaho State Legislature. Idaho Code 63-3022B – Deduction for Energy Efficiency Upgrades The age cutoff reflects that homes built after that point were already being constructed to an energy code.
Which Upgrades Qualify
The statute defines a qualifying “energy efficiency upgrade measure” as an improvement to the building envelope or duct system that meets or exceeds the minimum performance values in the version of the International Energy Conservation Code (IECC) in effect in Idaho when the work is done. Idaho currently references the 2018 IECC.2Idaho State Legislature. Idaho Code 39-9701 – Idaho Energy Conservation Code Within that definition, qualifying measures are:
- Insulation added on top of existing insulation (not a replacement for what’s already there)
- Replacement windows more efficient than the ones removed
- Storm windows installed over existing windows
- Weather stripping and caulking that seals the building envelope
- Duct sealing and insulation, with joints mechanically fastened and sealed with mastic sealant
Ask your contractor for product documentation showing the materials meet or exceed the IECC thresholds. A retrofit specialist should know what qualifies, but keep the paperwork rather than relying on their word.1Idaho State Legislature. Idaho Code 63-3022B – Deduction for Energy Efficiency Upgrades
What the Deduction Does Not Cover
This is where homeowners most often get the rules wrong, usually because they are thinking of the federal credits rather than the Idaho deduction. The 63-3022B deduction does not cover:
- HVAC equipment, including heat pumps and furnaces
- Solar panels and other on-site renewable systems
- Water heaters
- Appliances
It is a building-shell and ductwork deduction. Anything mechanical sitting inside the house falls outside it.1Idaho State Legislature. Idaho Code 63-3022B – Deduction for Energy Efficiency Upgrades
One trap inside the insulation rule: the statute requires added insulation to supplement what is already in place. If you tear out old insulation and install new in its place, that expense may not qualify. Plan the work accordingly.
How to Claim the Deduction
The deduction is based on actual costs paid or accrued during the tax year, so you claim it in the year the work is completed and paid for. It reduces your taxable income rather than acting as a dollar-for-dollar credit against tax owed, so the real savings depend on your Idaho marginal rate. There is no statutory cap on the amount you can deduct.
Keep:
- Receipts and invoices showing what you paid and when
- Product documentation or energy efficiency certifications proving the materials meet the IECC performance values in effect in Idaho when the work was done
- Proof the residence meets the pre-2002 construction test, if that is ever questioned
Enter the deduction on your Idaho individual income tax return under the adjustments allowed by Idaho Code 63-3022B.
What Else Is Available in Idaho
The federal residential energy tax credits that many homeowners used from 2023 through 2025 no longer apply to property placed in service after December 31, 2025. The Energy Efficient Home Improvement Credit under Section 25C, which covered 30% of qualifying improvements with annual limits of $1,200 for most measures and $2,000 for heat pumps and biomass stoves, does not apply to improvements made in 2026 or later.3Office of the Law Revision Counsel. 26 USC 25C – Energy Efficient Home Improvement Credit The Residential Clean Energy Credit under Section 25D, which covered 30% of solar, battery storage, wind, and geothermal costs, also does not apply to expenditures made after December 31, 2025.4Office of the Law Revision Counsel. 26 USC 25D – Residential Clean Energy Credit If you completed qualifying work before the end of 2025, claim those credits on your 2025 federal return.
With the federal credits gone, two Idaho programs are worth knowing about alongside the state deduction.
State Energy Loan Program
The Idaho Governor’s Office of Energy and Mineral Resources runs a low-interest loan program for energy efficiency projects on single-family homes. Loans go up to $40,000, with three term options: 3 years at 3% interest, 5 years at 5%, or 7 years at 7%. There are no income requirements, but applicants must pass a credit check and provide a warranty deed or recent deed of trust. A nonrefundable $100 credit analysis fee applies. Applications are processed first-come, first-served until funding is exhausted or December 31, 2026, whichever comes first.5Governor’s Office of Energy and Mineral Resources. State Energy Loan Program If this program is part of your plan, apply early; the deadline and the funding cap can both close the door.
Utility Programs
Idaho Power offers a weatherization program for income-qualified customers that provides free energy efficiency upgrades valued at up to $6,000. A certified weatherization auditor evaluates the home and determines the improvements, which can include insulation and weather stripping. The home must be heated with electricity supplied by Idaho Power, and you apply through a local Community Action Partnership agency.6Idaho Power. Weatherization Programs Idaho Power also runs a Heating and Cooling Efficiency Program with incentives that change over time. Avista and Rocky Mountain Power serve other parts of the state with their own programs, so check with whichever utility bills you.
Income-qualified customers may also be able to access no-cost or low-cost efficiency work through the Bonneville Power Administration’s Income Qualified Energy Conservation Program, delivered through local utility partners rather than directly from BPA.7Bonneville Power Administration. Income Qualified
The Idaho deduction and these programs stack. A homeowner can take a State Energy Loan to finance qualifying envelope work on a pre-2002 home and still deduct the full cost under 63-3022B in the year the work is paid for.