Repair or Replace? How to Decide for Every Major Home System
The 50% rule, expected lifespans, and system-by-system guidance for the repair-or-replace decision on HVAC, water heaters, roofs, and appliances.
Every homeowner eventually stands over a dead appliance doing mental math with a contractor on the phone. Here's the framework to decide in minutes instead of days.
The 50% rule
If a repair costs more than half the price of replacement and the unit is past half its expected life, replace it. You're otherwise paying premium money to extend a countdown that's nearly finished.
System by system
- Furnace (15–20 yrs): repair under 12 years old; at 15+, put repair money toward a new, more efficient unit.
- AC (12–15 yrs): a failed compressor on an older unit is a replacement, not a repair — and older refrigerant types make fixes disproportionately pricey.
- Water heater (8–12 yrs): a leaking tank is done, full stop. Element and valve repairs are fine on younger units.
- Roof (20–25 yrs asphalt): isolated damage repairs well; widespread curling or granule loss means budgeting for replacement.
- Appliances (10–15 yrs): one cheap fix is fine; the second repair on an old unit is the universe telling you something.
Factor in the efficiency gap
A 20-year-old furnace or water heater can be dramatically less efficient than today's equivalent — the energy savings partially finance the replacement, and rebates or tax credits often sweeten it further.
Repairs buy time. The question is always what that time costs — and what it's protecting you from deciding.
Frequently asked
Should I replace things proactively before they fail?
For failure-prone, high-damage items — water heaters and washing machine hoses — yes, replacing on schedule beats mopping up. For most systems, run them while budgeting for the known end date. Lena can build the timeline for your home's systems.
Are home warranties a good middle ground?
Sometimes, for older homes with aging systems — but read the coverage caps, service fees, and exclusions. They manage cash flow more than they save money overall.
Keep reading
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Which staging efforts move the sale price and which just burn money — from decluttering and paint to whether professional staging is worth it.
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