Gas Furnace
Powerful forced-air heating using natural gas for cold climates.
About Gas Furnace
Gas furnaces are the most common heating system in the US, burning natural gas to produce heat distributed through ductwork. Modern high-efficiency models reach 96-98% AFUE, meaning nearly all fuel becomes usable heat. Gas furnaces excel in cold climates where powerful, fast heating is needed.
Pros
- Powerful heating for cold climates
- Fast heat output (warms home quickly)
- Natural gas is often cheapest heating fuel
- Reliable in extreme cold
- Well-understood technology with many contractors
- Works with central AC for year-round comfort
- Lower upfront cost than heat pumps
Cons
- Heating only - requires separate AC for cooling
- Requires natural gas line
- Carbon monoxide risk (requires CO detectors)
- Combustion creates greenhouse gas emissions
- Annual safety inspection recommended
- Ductwork required
- Rising natural gas prices in some areas
Best For
- Cold climates with harsh winters
- Areas with affordable natural gas
- Homes with existing ductwork
- Pairing with central AC
- Homeowners prioritizing low upfront cost
- Backup heating for heat pump systems (dual-fuel)
Popular Gas Furnace Brands
Frequently Asked Questions
What AFUE rating should I get?
80% AFUE is minimum code in most areas. 90%+ (condensing) models save significantly in cold climates. 96%+ is the sweet spot for value in areas with 5,000+ heating degree days.
Single-stage vs two-stage vs modulating?
Single-stage: cheapest, on/off only. Two-stage: runs at low and high speed for better comfort. Modulating: adjusts continuously for the most even heat and lowest noise. Each step up costs 20-30% more.
How often should a gas furnace be serviced?
Annually before heating season (September-October). Professional service includes safety inspection, cleaning, and performance testing. This is especially important for CO safety.