Homeowner Tips
Repair or Replace? A 2026 Decision Framework for 12 Home Systems
The 50% rule, remaining-life math and a system-by-system table for roofs, HVAC, water heaters, windows, decks and more.
The two rules that settle most cases
Rule one, the 50% rule: if the repair costs more than half of full replacement, replace. You are otherwise paying half price for a fraction of the remaining life.
Rule two, remaining-life math: divide the repair cost by the years of service it realistically buys, and divide the replacement cost by its expected lifespan. Whichever produces the lower cost per year wins. A $900 repair buying 3 years is $300/yr; a $7,500 replacement lasting 25 years is $300/yr — a tie, and in a tie you replace, because the new system carries a warranty and better efficiency.
System-by-system decision table
| System | Expected life | Repair if… | Replace if… | Replacement cost |
|---|---|---|---|---|
| Asphalt roof | 20–30 yrs | Localized leak, under 15 yrs old | Granule loss sitewide, 2+ layers, 18+ yrs | $9,000 – $28,000 |
| Gas furnace | 15–25 yrs | Under 12 yrs, part under $600 | Cracked heat exchanger, 15+ yrs | $4,500 – $10,000 |
| AC / heat pump | 12–18 yrs | Under 10 yrs, not a compressor | Compressor failure, R-22 refrigerant | $5,500 – $14,000 |
| Tank water heater | 8–12 yrs | Thermostat or element only | Tank leak, any age | $1,400 – $3,500 |
| Windows | 20–40 yrs | Hardware, single unit seal | Rot at sill, fogged sitewide | $450 – $1,400 each |
| Vinyl siding | 25–40 yrs | A few panels, color matches | Widespread cracking, moisture behind | $8,000 – $24,000 |
| Wood deck | 10–20 yrs | Boards only, frame is sound | Any framing or ledger rot | $8,000 – $30,000 |
| Electrical panel | 25–40 yrs | Adding a breaker with slots free | FPE/Zinsco, no slots, 40+ yrs | $2,200 – $4,500 |
| Galvanized supply pipe | 40–70 yrs | One accessible section | Low pressure at multiple fixtures | $4,500 – $12,000 |
| Sewer lateral (clay) | 50–60 yrs | Single root intrusion, cleanable | Bellied, collapsed, repeat backups | $3,500 – $15,000 |
| Garage door opener | 10–15 yrs | Sensor, remote, gear kit | Motor failure, no rolling code | $450 – $1,200 |
| Kitchen cabinets | 20–50 yrs | Boxes are sound and square | Water damage, particleboard swelling | $6,000 – $25,000 |
The three factors that override both rules
Safety beats economics. A cracked heat exchanger, an FPE panel or a deck ledger pulling away from the house gets replaced whatever the math says.
Access cost is the second override. If replacing a component requires opening a finished ceiling, replace everything behind that ceiling while it is open — the demolition and repair are the expensive part, not the parts.
Sale timing is the third. If you are selling within two years, a repair that passes inspection and is honestly disclosed is often the better financial move; buyers rarely pay a full premium for a system they did not choose.
Get a second opinion on any five-figure diagnosis
Compressor failures, cracked heat exchangers and 'the whole roof needs to go' are the three diagnoses most often delivered by the party who profits from the replacement. A $150 second inspection on a $9,000 decision is one of the highest-return dollars in homeownership.
Ask for photographs of the defect, the model and serial number, and the manufacturer's stated life expectancy. A legitimate contractor produces all three without hesitation.
Tools & guides for this project
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