Free tool · Decide with numbers
Repair or Replace? Calculator
Your water heater, furnace, AC or roof needs a repair. Is it worth it, or is it time for a new one? Enter the age and the two prices and get a clear answer, using the 50% rule, the $5,000 rule for HVAC, and the cost per year of use.
- 9 home systems
- 3 rules combined
- Explains the result
- No sign-up
Your numbers
How long home systems last
Typical lifespans and installed replacement prices used by the calculator. Change the replacement price above to match your own quote.
| System | Typical lifespan | Typical replacement |
|---|---|---|
| Tank water heater | 8–12 years | about $1,450 |
| Tankless water heater | 15–20 years | about $3,500 |
| Gas furnace | 15–20 years | about $5,000 |
| Central air conditioner | 12–17 years | about $6,000 |
| Heat pump | 10–15 years | about $8,000 |
| Asphalt shingle roof | 20–30 years | about $14,000 |
| Sump pump | 7–10 years | about $800 |
| Garbage disposal | 8–15 years | about $425 |
| Electrical panel | 25–40 years | about $2,500 |
The three rules behind the answer
- The 50% rule. If the repair costs half or more of a new unit, replacing is usually the better use of money.
- The $5,000 rule (heating and cooling). Age multiplied by repair cost. Over 5,000 points to replacement.
- Cost per year of use. We divide the repair by the years it is likely to buy you and compare it with what a new unit costs per year of its life. If the repair costs more per year, it's poor value.
Rules of thumb don't know everything about your home. Efficiency, rebates, warranty and how long you'll stay in the house matter too.
Frequently asked questions
What is the 50 percent rule for repair or replace?
If a repair costs half or more of what a new unit would cost, replacing usually makes more sense, especially when the equipment is past the middle of its expected life.
What is the $5,000 rule for HVAC?
Multiply the age of your furnace, AC or heat pump by the repair cost. If the result is more than $5,000, many technicians suggest replacing instead of repairing. For example, a 12-year-old AC with a $500 repair gives 6,000, which points to replacement.
How long do water heaters, furnaces and AC units last?
Tank water heaters usually last about 8 to 12 years, tankless units 15 to 20, gas furnaces 15 to 20, central air conditioners 12 to 17 and heat pumps 10 to 15. Maintenance, water quality and climate move these numbers.
When should I replace instead of repair no matter the cost?
Replace when there is a safety problem that can't be fixed properly, such as a leaking water heater tank, a cracked furnace heat exchanger, or a panel brand known for failing breakers, and when parts are no longer available.
Does a new system pay for itself in energy savings?
Sometimes partly. Replacing a very old AC, furnace or water heater with an efficient one can cut running costs, and federal or utility rebates may apply, but savings alone rarely cover the full price quickly.
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