Furnace vs. Boiler: Which Costs Less?
Which one to pick
A furnace is usually cheaper to install and the practical choice if you already have ducts — and it shares those ducts with central air, so you get heating and cooling from one duct system. A boiler costs a bit more but delivers quieter, more even heat with no blown dust, and boilers often last longer. Pick a furnace for lower upfront cost and easy AC; pick a boiler for comfort, air quality, and radiant-floor heat. Your existing setup (ducts vs. radiators) usually points the way.
When it’s time for a new heating system, homes without forced air often face a real fork: furnace or boiler. A furnace blows warm air through ducts; a boiler circulates hot water to radiators or radiant floors. The cheaper, more flexible option usually depends on what your home already has.
A furnace is typically a little cheaper and doubles up with central AC through shared ducts. A boiler costs a bit more but heats more evenly and quietly, with no blown dust. Here’s how they compare on cost and comfort.
| Factor | Furnace (forced air) | Boiler (hydronic) |
|---|---|---|
| Installed cost | $3,000 – $7,500 | $3,500 – $8,500 |
| How it heats | Blows warm air through ducts | Circulates hot water to radiators/floors |
| Comfort | Fast; air can feel drier | Even, steady, quiet warmth |
| Also runs AC? | Yes — shares ducts with central AC | No — cooling needs a separate system |
| Air quality | Moves dust; needs filter changes | No blown air or dust |
| Lifespan | 15 – 20 years | 15 – 30 years |
| Best for | Homes with ducts, wanting AC too | Even heat, allergy concerns, radiant floors |
Common questions
- Is a furnace or boiler cheaper?
- A furnace is usually a bit cheaper to install — $3,000–$7,500 versus $3,500–$8,500 for a boiler — especially if ducts already exist. Operating cost depends on fuel prices and your home's efficiency.
- Which heats more evenly?
- A boiler. Hot water circulated through radiators or radiant floors gives steady, even warmth with no drafts or blown air, which many people find more comfortable than a furnace's bursts of hot air.
- Can a boiler run my air conditioning?
- No. Boilers only heat, so you'd need a separate cooling system (like a mini-split or central AC). A furnace shares ductwork with central air, which is why duct-and-furnace homes get both from one system.
- Which lasts longer, a furnace or a boiler?
- Boilers often last longer — 15–30 years versus 15–20 for a furnace — partly because they have fewer moving parts. Both last longest with regular maintenance.
How we estimate: We checked these prices against the 2026 sources listed below (see how we get our numbers). Your price depends on where you live, so get two or three written bids.
Sources
We checked the prices on this page against 2026 numbers from these sources:
- New Furnace Replacement Cost (2026), HomeGuide
- Boiler Replacement Cost (2026), HomeGuide
- How Much Does a Furnace Cost?, This Old House