Furnace vs Boiler in King County, Washington
When a furnace makes sense
If your house already has ductwork, a furnace is the straightforward choice. Those same ducts are already in place, and with heat needed about 10 months a year here, that matters. A furnace runs on natural gas and heats only, so you're still looking at separate equipment for cooling.
When a boiler makes sense
If your home heats through radiators or in-floor pipes rather than ducts, a boiler fits what's already there. It also runs about 5% cheaper here than a furnace, and with winter nights averaging 32°F from December through February, that difference adds up over a heating season this long. Like a furnace, it runs on natural gas and only heats, so cooling would need to come from somewhere else.
When a furnace makes sense
If your house already has ductwork, a furnace is the straightforward choice. Those same ducts are already in place, and with heat needed about 10 months a year here, that matters. A furnace runs on natural gas and heats only, so you're still looking at separate equipment for cooling.
When a boiler makes sense
If your home heats through radiators or in-floor pipes rather than ducts, a boiler fits what's already there. It also runs about 5% cheaper here than a furnace, and with winter nights averaging 32°F from December through February, that difference adds up over a heating season this long. Like a furnace, it runs on natural gas and only heats, so cooling would need to come from somewhere else.
Furnace
- Runs on
- Natural gas
- What it does
- Heats only
- Tax credit
- No federal tax credit since the end of 2025
Sources: U.S. Department of Energy · Internal Revenue Code
Boiler
- Runs on
- Natural gas
- What it does
- Heats only
- Tax credit
- No federal tax credit since the end of 2025
Sources: U.S. Department of Energy · Internal Revenue Code
Furnace wins in King County.
In the Pacific states, 56.9% of homes heat with a furnace, so just over half already have the ductwork it needs.
If your home already has radiators or in-floor pipes instead of ductwork, a boiler is still the better fit.
Find a contractor| Compared on | Furnace | Boiler |
|---|---|---|
| Cost to run here | Costs more to run | About 5% less to run |
| What it does | Heats only | Heats only |
| Homes in the Pacific states that heat with one | 56.9% | 1.6% |
| Handles a 32°F night | Yes | Yes |
Sources: U.S. Energy Information Administration, U.S. Department of Energy, NOAA
When a furnace makes sense
If your house already has ductwork, a furnace is the straightforward choice. Those same ducts are already in place, and with heat needed about 10 months a year here, that matters. A furnace runs on natural gas and heats only, so you're still looking at separate equipment for cooling.
When a boiler makes sense
If your home heats through radiators or in-floor pipes rather than ducts, a boiler fits what's already there. It also runs about 5% cheaper here than a furnace, and with winter nights averaging 32°F from December through February, that difference adds up over a heating season this long. Like a furnace, it runs on natural gas and only heats, so cooling would need to come from somewhere else.
A King County contractor will price both against your own house, your ductwork and your panel.
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