InstaBidsFor homeowners
Boiler vs furnace: should you keep pipes or ducts?
Choose Boiler for retaining piped radiator or radiant-floor heat; Furnace for retaining ducted warm-air heat. The right choice depends on fuel and equipment rating (gas AFUE label thresholds: 90%, 95%, or 97%), domestic hot-water needs, and the written installation scope.
| Factor | Boiler | Furnace |
|---|---|---|
| retaining piped radiator or radiant-floor heat | Hot water or steam through piping to radiators, baseboards, or radiant floors (DOE, 2022). | Heated air through ducts (DOE, 2022). |
| retaining ducted warm-air heat | Hot water or steam through piping to radiators, baseboards, or radiant floors (DOE, 2022). | Heated air through ducts (DOE, 2022). |
| Published installed guide range; USD per system, 2026 | Carrier, October 2026: $4,290–$10,070 per boiler replacement installed; guide cites This Old House. Not a bid. | Carrier, October 2026: approximately $3,800–$12,000 per gas furnace installed. Not a bid. |
| Historical DOE lifetime-model estimates; gas classes only | 26.5 years: hot-water gas-fired boilers, DOE 2016 rule lifetime model (historical data and survey). | 21.5 years: national average for non-weatherized and mobile-home gas furnaces, DOE 2023 rule lifetime model. |
| Current ENERGY STAR AFUE criteria; fuel and region matter | Gas boilers: 90% or greater; oil boilers: 87% or greater (EPA; read 6 November 2026). | U.S. North gas furnaces: 97% or greater (EPA; read 6 November 2026). |
| HUD multifamily capital-planning estimates, undated | 25 years: centralized sectional gas boiler, Centralized HVAC block, row 3.4.2.1.2; family/elderly columns. | 20 years: gas furnace/air handler, Decentralized and Split HVAC block, row 3.4.3.1.4; family/elderly columns. |
| Routine maintenance | EPA: annual pre-season heating check-up. | EPA: inspect, clean, or change furnace air filters once a month. |
| Domestic hot-water integration | DOE: combination units can provide both space and water heating. | A forced-air furnace distributes heated air; specify the separate hot-water arrangement (DOE, 2022). |
InstaBids is an AI-run marketplace for homeowners and property managers: describe a home job once, by chat or through your own AI assistant, add photos, and get multiple written quotes on the same scope, compared apples to apples, with no phone calls or home visits before you pick.
Post your job on InstaBids, and contractors can bid in writing on one written scope.
- Describe it onceBy chat, or through your own AI assistant, and add photos.
- Post it and send itContractors bid in writing on that scope.
- Compare line by lineEvery quote is written against the same scope.
- You chooseContact details stay hidden until you pick and they confirm.
For your AI assistant
MCP connector · REST API · plain HTMLHand any of these to your assistant and it can help you write this job's request; you send the request yourself. What you type in the job box above goes into the prompt these buttons carry. The connector asks you to sign in to your InstaBids account the first time.
- MCP connector URL
https://instabids.ai/api/agent/mcp - Agent API (OpenAPI)
https://instabids.ai/openapi.json - Start-request link
https://instabids.ai/intake?trade=hvac&from=options-compare--boiler-vs-furnace&utm_source=us&utm_medium=page&utm_campaign=options&page_type=options#job=boiler%20or%20furnace%20replacement - Prompt for any AI, with your job
- ChatGPTOpens with the prompt
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- GrokOpens with the prompt
- GeminiCopies the prompt, then opens
Every page is plain HTML. Steps for every assistant: add to your assistant.
Do houses still use boilers?
Yes. DOE’s 2022 Energy Saver Guide describes boiler heat delivered through pipes to radiators, baseboard convectors, or radiant floors. EPA’s ENERGY STAR boiler criteria specify gas-boiler AFUE ratings of 90% or greater and oil-boiler ratings of 87% or greater. Sources read 6 November 2026.
For an existing radiator system, identify the heating medium and fuel before comparing boiler replacement with conversion to forced air.
What are the downsides of using a boiler?
Boiler replacement and conversion to furnace ducts are different scopes. DOE describes pipe-fed radiators, baseboards, and radiant floors for boilers; furnaces use ducts. Carrier’s October 2026 guide publishes $4,290–$10,070 per boiler replacement installed, citing This Old House. Sources read 6 November 2026.
Ask whether the boiler bid retains the existing radiators or radiant-floor tubing, and list any distribution changes separately.
Do you need a boiler if you have a furnace?
A furnace provides ducted space heat; a boiler delivers heat through water or steam piping. DOE states, “Combination units can provide space and water heating.” A furnace proposal should identify the separate domestic-hot-water arrangement, while a boiler proposal should identify whether a combination appliance is included. Source read 6 November 2026.
What lasts longer, a furnace or a boiler?
DOE’s historical gas-equipment models used 26.5 years for hot-water gas-fired boilers (2016) and 21.5 years for non-weatherized and mobile-home gas furnaces (2023). The figures describe different modeled populations and cannot predict which appliance will last longer in your home; sources read 6 November 2026 and 28 October 2026, respectively.
Is a boiler better than a furnace?
A boiler suits retaining piped radiator or radiant-floor heat; a furnace suits retaining ducted warm-air heat. EPA’s ENERGY STAR gas criteria differ: 90% AFUE for boilers, 95% for U.S. South furnaces, and 97% for U.S. North furnaces. Sources read 6 November 2026.
Domestic-hot-water needs also affect the scope: DOE describes combination units that provide space and water heating. Name the proposed boiler or furnace model and compare its actual AFUE, rather than treating a category’s label threshold as its measured performance.
What should a boiler or furnace written scope include?
Heat-delivery system: name the existing radiators, baseboard convectors, radiant-floor tubing, or furnace ducts; state which boiler pipes or furnace ducts stay and which distribution components change.
Fuel and equipment rating: list the proposed boiler or furnace model and AFUE; EPA’s boiler label criteria distinguish gas at 90% from oil at 87%.
Gas-furnace region: state which ENERGY STAR criterion is being used, 95% AFUE for U.S. South or 97% for U.S. North.
Domestic hot water: state whether the boiler proposal includes a combination unit serving both space heat and water heating.
Maintenance handoff: include the annual heating visit and, for furnace air filters, the monthly inspection, cleaning, or change task.
Comfort observations: list rooms that are too hot or too cold; EPA names equipment operation, duct problems, and inadequate insulation as possible causes. DOE also names frequent repairs with rising energy bills as a reason to assess the system.
Written total and inclusions: separate the boiler or gas-furnace installation from distribution changes; the 2026 Carrier ranges describe installed equipment guides rather than a bid for this home.