Furnace vs. Boiler: Which Costs Less?
The verdict
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 |
Frequently asked 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: ranges are cross-checked against current 2026 industry sources (see our data & methodology). Your actual cost depends on local rates — always get multiple written quotes.
Sources
Cost ranges on this page were checked against current (2026) data from these industry sources:
- New Furnace Replacement Cost (2026) — HomeGuide
- Boiler Replacement Cost (2026) — HomeGuide
- How Much Does a Furnace Cost? — This Old House