Quick Answer
Any improvement that adds value, prolongs your home's life, or adapts it to new uses increases cost basis. This includes renovations ($25,000+ kitchen remodel), additions, major system replacements, and permanent installations — but not routine repairs or maintenance.
Best Answer
Michelle Woodard, JD
Best for homeowners who've done major renovations and need to maximize their cost basis calculations
The IRS test for cost basis improvements
According to [IRS Publication 523](https://www.irs.gov/pub/irs-pdf/p523.pdf), an improvement increases your cost basis if it:
1. Adds to the value of your home
2. Prolongs the useful life of your home
3. Adapts your home to new uses
This is more expansive than many homeowners realize.
Major improvements that definitely increase basis
Structural and system improvements:
Outdoor improvements:
Example: Comprehensive renovation cost basis calculation
Let's track a homeowner's improvements over 10 years:
Original purchase (2016): $350,000
Year 1: Kitchen remodel: $35,000
Year 3: New roof: $12,000
Year 4: Bathroom remodel: $18,000
Year 6: HVAC replacement: $9,000
Year 7: Deck addition: $8,000
Year 9: Basement finishing: $25,000
Year 10: New windows: $7,000
Total improvements: $114,000
New cost basis: $350,000 + $114,000 = $464,000
When selling for $650,000:
Improvements vs. repairs: The key distinction
Improvements (increase basis):
Repairs (don't increase basis):
Lesser-known improvements that increase basis
Many homeowners miss these qualifying improvements:
Accessibility modifications:
Security and technology:
Energy efficiency:
What you should do
1. Keep detailed records: Save contracts, receipts, permits, and photos
2. Track labor and materials separately: Both count toward basis
3. Include related costs: Permits, architectural fees, contractor costs
4. Document the "before" condition: Photos help prove it was an improvement
5. Organize by year: This helps with depreciation calculations if you rent the property
According to [IRS Publication 551](https://www.irs.gov/pub/irs-pdf/p551.pdf), you must have documentation to support basis additions, and the burden of proof is on you.
Key takeaway: Virtually any permanent improvement that enhances value, extends life, or adapts your home increases cost basis — proper documentation of $100,000+ in improvements can save $15,000-25,000 in capital gains taxes.
Key Takeaway: Nearly all permanent home improvements increase cost basis, and proper documentation of major renovations can save $15,000-25,000 in capital gains taxes when selling.
Common home projects and their cost basis treatment
| Project Type | Typical Cost | Increases Basis? | Key Factor |
|---|---|---|---|
| Kitchen remodel (full) | $25,000-35,000 | Yes | Adds value and functionality |
| Roof replacement | $10,000-15,000 | Yes | Extends home life substantially |
| HVAC system upgrade | $6,000-10,000 | Yes | Better than original system |
| Bathroom renovation | $12,000-20,000 | Yes | Adds value and modernizes |
| Flooring replacement | $4,000-8,000 | Yes | Better materials than original |
| Interior painting (routine) | $2,000-4,000 | No | Maintenance, not improvement |
| Deck/patio addition | $6,000-12,000 | Yes | Adds new living space |
| Landscaping (permanent) | $3,000-8,000 | Yes | Enhances property value |
| Plumbing repairs | $500-2,000 | No | Restores original function |
| Window replacement | $5,000-10,000 | Yes | Usually better than original |
More Perspectives
Robert Kim, CPA
Best for homeowners preparing to sell who want to understand which of their improvements count
If you're getting ready to sell
As you prepare for sale, you're probably wondering which of your home projects will reduce your tax bill. The good news: most significant improvements count toward your cost basis.
The simple test: Does it add value or extend life?
If you improved something rather than just fixed it, it likely increases your basis:
Clear "yes" improvements:
Common "no" repairs:
What many sellers forget to include
Outdoor improvements:
Interior improvements:
How to reconstruct your improvement costs
If you don't have perfect records:
1. Review old tax returns: Look for energy credit claims
2. Check bank statements: Search for large home-related payments
3. Contact previous contractors: Many keep records for years
4. Use permit records: Your city may have improvement permits on file
Example for a typical seller
Home purchased 2018: $280,000
Improvements over 6 years:
Total basis: $280,000 + $41,000 = $321,000
Selling for $420,000:
Without tracking improvements, the gain would have been $140,000 — dangerously close to the exclusion limit.
Key takeaway: Most permanent home improvements increase your cost basis — even small projects add up to significant tax savings when selling.
Key Takeaway: Most permanent improvements count toward cost basis, and even small projects can add up to significant tax savings for home sellers.
Michelle Woodard, JD
Best for homeowners who've done a mix of repairs and improvements and need to sort them out
Sorting improvements from repairs
Many homeowners have done a mix of repairs and improvements over the years. The key is understanding which expenses increase your basis and which don't.
The "betterment" test
The IRS uses a "betterment" standard: Did the work make your home better than it was before, or just restore it to previous condition?
Examples of betterment (increases basis):
Examples of restoration (no basis increase):
Complex projects: Part improvement, part repair
Some projects involve both improvement and repair elements:
Roof project example:
Painting project example:
When repairs become improvements
Sometimes extensive repairs cross the line into improvements:
Documentation strategies for mixed projects
1. Separate invoices when possible: Ask contractors to itemize repairs vs. improvements
2. Keep before/after photos: Visual proof helps establish betterment
3. Save permits: Major improvements typically require permits; repairs often don't
4. Note the reason: "Emergency repair" vs. "upgrade" in your records
Common mixed scenarios
Kitchen project: $25,000 total
HVAC project: $8,500 total
According to [IRS Publication 523](https://www.irs.gov/pub/irs-pdf/p523.pdf), when in doubt, the IRS tends to view substantial work as improvement rather than repair.
Key takeaway: When projects involve both repairs and improvements, focus on documenting the betterment portion — substantial upgrades are generally treated as basis-increasing improvements.
Key Takeaway: For mixed repair/improvement projects, focus on documenting the betterment portion, as substantial upgrades typically qualify as basis-increasing improvements.
Sources
- IRS Publication 523 — Selling Your Home - Rules for cost basis and capital gains
- IRS Publication 551 — Basis of Assets - How to determine and adjust basis
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Reviewed by Michelle Woodard, JD on February 28, 2026
This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.