Can I Replace My Own Furnace?
What this costs
| Option | Job | Low | High |
|---|---|---|---|
| Replace | Furnace Replacement | $2,950 | $8,350 |
The legal part is local
Seattle says you need a permit for any furnace replacement, and that a homeowner can get it. San Diego's simple permit is open to homeowners, property owners and licensed contractors. Rheem notes that some local codes require licensed installation. So ask your building department. A permit also means an inspection, which is your independent check.
Why this isn't a do-it-yourself job
We don't give steps for this work.
- Gas: a leak can cause a fire or explosion. Rheem warns of this in its first lines.
- Venting: CPSC says furnaces can malfunction and produce carbon monoxide, and that vents need to stay clear.
- Warranty: ask whether the maker's warranty requires professional installation. We didn't confirm this for each brand.
What you can do
Get more than one written quote. Ask each contractor about the permit, sizing, venting and the warranty. Verify the license on your state's lookup. Change filters and keep the area around the furnace clear. Those jobs are yours.
If you smell gas
Leave right away and call your utility or 911 from outside. If a CO alarm goes off, leave and call emergency services. Don't go back until responders say it's safe.
Furnace Won't Turn On? Safe Checks Before You Call
Common questions
Can I replace just the furnace and not the AC?
Can I replace the blower motor or gas valve myself?
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Last verified 2026-11-04
- City of Seattle: Furnace and refrigeration permits FAQ — Permit for any furnace replacement; homeowner can get a furnace or mechanical permit.
- City of San Diego: Simple no-plan mechanical permit — Furnace replacement permit available to homeowners and contractors.
- Rheem: *RA series gas furnace installation instructions — Intended for qualified individuals; some local codes require licensed personnel; fire or explosion warning.
- U.S. Consumer Product Safety Commission: Carbon monoxide fact sheet — Furnaces can malfunction and produce CO; keep vents clear.
- Public Service Commission of Wisconsin: Natural gas consumer safety — If you smell gas, leave immediately and call the gas utility's emergency number or 911 from a safe distance outdoors; odor described as rotten eggs, sulfur or garlic.
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.