CostYou've just closed on a home, and somewhere in the inspection report were ages for the roof, furnace, and water heater that you didn't think much about at the time.
Typical lifespans for major home systems
| Asphalt shingle roof | 20–25 years |
| Furnace | 15–20 years |
| Water heater | 8–12 years |
| Central air conditioner | 12–15 years |
| Windows | 20–30 years |
What usually happens without a plan
These are realistic ranges, not guarantees — a system can fail early or run well past its typical lifespan — but without any sense of where a home's major systems sit on this timeline, replacements land as complete surprises rather than predictable, budgetable events. A roof at year 22 failing isn't bad luck in the way a roof failing at year 4 would be; it's closer to an expected event that simply wasn't planned for financially.
How to actually budget for it
- Use your home inspection report as a starting baseline — most inspectors note the approximate age or condition of major systems.
- Set aside a maintenance reserve, even in years nothing breaks — a common rule of thumb is roughly 1% of a home's value per year, adjusted for the home's age and condition.
- Prioritize by both age and consequence — a roof near the end of its life is a bigger financial and structural risk to plan around than an aging water heater, even though the water heater has a shorter typical lifespan.
- Get ages confirmed for anything not obviously visible — a previous owner's receipts or permits, where available, beat guessing.
Who to ask
Ask your home inspector directly, during or right after the inspection, for their honest read on which systems are approaching end-of-life rather than relying only on the written report's general notes. A contractor or specialist (roofer, HVAC technician) can give a more precise read on a specific system if you want more certainty before a purchase or shortly after.
Factor a realistic maintenance reserve into your ongoing budget alongside your monthly mortgage payment.