Short answer
Keep records for improvements that add value, extend your home's life or adapt it to new uses. The IRS adds their cost to your home's basis, which lowers your gain when you sell. Examples include additions, a new roof or siding, a heating system, a septic system, a water heater and a kitchen remodel. Routine repairs such as painting or fixing leaks don't count. Keep records until 3 years after the tax return for the year you sell.
What counts as an improvement?
- Additions: bedroom, bathroom, deck, garage, porch, patio.
- Systems: heating, central air, furnace, duct work, wiring, security system.
- Exterior: new roof, siding, storm windows and doors.
- Plumbing: septic system, water heater, water softener or filtration.
- Grounds: landscaping, driveway, fence, retaining wall.
- Interior: built-in appliances, kitchen modernization, flooring, fireplace.
Source: IRS Publication 523.
What doesn't count?
Repairs and upkeep that keep the home in good shape without adding value, such as painting or fixing leaks. A repair done as part of a bigger project can count; replacing one broken pane is a repair, but replacing every window in a remodel is an improvement.
Why does it matter if I won't owe tax anyway?
Most owners can exclude a large gain when they sell; see do you pay tax when you sell your home. But a long stay, a big price rise, or renting the home first can change that, and good records help. They also help an appraiser and a buyer see what's been updated, which matters for well and septic homes; see well and septic in NH.
How should I keep them?
Save invoices, permits and before-and-after photos in one folder, with your closing papers. Tom doesn't give tax advice; a tax professional can tell you what applies to you.
Sources
Checked November 2, 2026. Rules and dates change, so confirm current details before you rely on them.
General information only, not tax or legal advice. Program availability, eligibility and terms vary by lender and are subject to change and to underwriting approval. Not a commitment to lend.