Ashburn, VA

How much does a gas boiler cost?

$2,200 – $7,000 standard-efficiency boiler cost
$4,000 – $10,000 high-efficiency boiler cost

Get free estimates from boiler installers near you, or view our cost guide below.

January 11, 2022

Reviewed by Tom Grupa and 3 expert boiler installers on HomeGuide.

Gas boiler prices

A gas boiler costs $3,200 to $9,000 to replace on average. Residential gas boiler prices are $1,200 to $7,000 for the unit alone, plus $1,000 to $3,500 for labor to install. Natural gas boiler prices depend on the type, brand, BTU output, and efficiency or AFUE rating.

Gas boiler cost to install - chart
Gas boiler cost to install - chart

Gas boiler cost
House size (square foot) Total replacement cost
1,200 – 2,000 $2,200 – $5,700
2,000 – 2,800 $2,400 – $6,200
2,800 – 3,600 $3,000 – $7,100
3,600 – 4,000 $3,200 – $7,300

*Prices are based on a standard-efficiency boiler.


Average cost to install a gas boiler

The following table shows the average cost to install a gas boiler.

Average cost to install a gas boiler
National average cost $6,500
Minimum cost $2,200
Maximum cost $12,000
Average cost range $3,200 to $9,000

Cost data is from research and project costs reported by HomeGuide members.

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Natural gas boiler installation
Natural gas boiler installation

High-efficiency gas boiler prices

New high-efficiency gas boiler prices are $1,900 to $7,000 on average. High-efficiency gas boiler installation costs $4,000 to $10,000, including the unit. Standard units have 80% to 89% energy efficiency, while high-efficiency Energy Star units are 90%+ efficient.

High-efficiency gas boiler cost
Boiler type AFUE rating Unit prices Total replacement cost
Standard efficiency 80% – 89% $1,200 – $5,000 $2,200 – $7,000
High-efficiency 90% – 95%+ $1,900 – $7,000 $4,000 – $10,000
  • The Annual Fuel Utilization Efficiency (AFUE) measures the percentage of fuel that converts to heating output. Higher AFUE units lower utility bills.
  • Another term for high-efficiency boilers is “condensing boilers.”

Gas combi boiler installation cost

A gas combi boiler installation costs $6,000 to $10,000 on average when replacing an old boiler or water heater. New gas central heating combi boiler prices are $1,700 to $4,000, excluding installation. Combi boilers are tankless systems that fit into smaller spaces.

  • All combi boilers have a minimum of 90% AFUE efficiency rating.
  • Combi boilers heat water quickly, but their heating capacity is best for dwellings with one bathroom.
  • Alternatively, a tankless water heater installation costs $800 to $3,500, but only produces hot water for cleaning and not for home heating.

Natural gas boiler prices by size and type

Natural gas boiler prices range from $2,200 to $9,500, depending on the BTU output sizes, system type, and mounting location. Direct replacements with the same model and connections are the cheapest.

Natural gas boiler installation cost by BTU
BTU output Unit cost Total installation cost
60,000 $1,200 – $2,100 $2,200 – $5,600
80,000 $1,400 – $2,300 $2,400 – $5,800
90,000 $1,500 – $2,600 $2,500 – $6,100
110,000 $1,900 – $2,800 $2,900 – $6,300
120,000 $2,000 – $3,300 $3,000 – $6,800
150,000 $2,200 – $3,800 $3,200 – $7,300
180,000 $3,000 – $4,200 $4,000 – $7,700
200,000 $4,500 – $6,000 $5,500 – $9,500
  • Most residential gas boiler sizes are 60,000 to 200,000 BTUs.
  • The AFUE rating determines the heating output. A unit with 100,000-BTU heating input and a 95 AFUE rating has a heating output of 95,000 BTUs.

What size gas boiler do I need?

Most homes need 25 to 50 BTUs per square foot, depending on the home’s square footage, climate zone, insulation, heating needs, and the boiler efficiency or AFUE rating.

Boiler BTU's per square foot
Climate / region BTUs per square foot
Hot climate / Southern U.S. 20 – 40
Moderate climate / Central U.S. 40 – 50
Coldest climate / Northern U.S. 50 – 60

Gas-fired water vs. steam boiler prices

Gas-fired water boiler prices are $1,700 to $4,500, while natural-gas steam boiler prices are $2,000 to $6,000 on average. Steam boilers are typically larger and more powerful units that run at higher temperatures for commercial settings.

Steam boiler vs. gas-fired water boiler cost
Boiler heating-point types Unit prices
Hot-water / hydronic $1,700 – $4,500
Steam $2,000 – $6,000

*Material prices only.

Floor-standing vs. wall-mounted gas boiler cost

A wall-mounted boiler costs $2,000 to $5,000 on average. These models are typically tankless and save space by venting through the wall. Most larger gas boilers are floor-standing with greater heating capacities and more features.

Floor-standing vs. wall-mounted gas boiler cost
Boiler install location Unit prices
Wall-mounted $2,000 – $5,000
Floor-standing $1,200 – $6,000

*Material prices only.

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Residential gas boiler prices by brand

A new residential gas boiler costs $1,200 to $6,500 for the unit alone. Gas system boiler prices depend on the brand, size, and efficiency rating.

  • Weil McLain gas boiler prices are $1,700 to $6,000.
  • New Yorker gas boiler prices are $1,700 to $3,300.
  • Lennox gas boilers prices are $1,700 to $6,500.
  • Slant Fin gas boiler prices are $1,700 to $5,300.
  • Utica gas boiler prices are $1,200 to $5,400.
Compare gas boiler prices by brand
Brand Price range
Buderus $2,600 – $5,000
Carrier $2,200 – $5,800
Lennox $1,700 – $6,500
LAARS $1,200 – $6,200
Navien $2,000 – $4,200
New Yorker $1,700 – $3,300
Slant-Fin $1,700 – $5,300
Peerless $2,000 – $6,000
Triangle Tube $2,000 – $5,400
Utica $1,200 – $5,400
Weil-McLain $1,700 – $6,000
Westinghouse $2,500 – $2,800

*For residential units up to 200,000 BTU, excluding installation labor.

Gas boiler replacement cost factors

Additional boiler replacement costs include:

  • Boiler removal – Removing an old gas boiler costs $200 to $500 on average with disposal, and this fee is typically part of the replacement labor costs.
  • MaintenanceAnnual boiler service costs $200 to $500 and includes a heating system inspection, leak testing, and cleaning.
  • Thermostat upgrade – A thermostat replacement costs $140 to $350 for upgrading to an energy-saving model.
  • Conversion to propane – A propane conversion kit costs $30 to $140 plus labor.
  • New gas lineGas line installation costs $12 to $25 per linear foot.
  • Permit – A gas-boiler replacement permit costs $50 to $250, depending on the location and number of new connections required. Contractors typically pull all permits.
  • Hazardous materialsAsbestos removal costs $20 to $65 per square foot to dispose of old hazardous lining on outdated boilers.
  • Home energy audit – A complete Manual J heating load calculation costs $200 to $500 to determine the exact size needed for a new boiler.
  • Fitting – Direct replacements with the same boiler model type have the lowest labor costs. Boiler upgrades, connection or location changes, and system modifications increase labor costs.
  • Water line installation – Installing new pipes or pipe replacement costs $450 to $1,800 for a new boiler connection.
  • Rebates – Replacing an old gas boiler may qualify for rebates, depending on the location, seller, and natural gas provider.
  • Boiler type – Combination hot water heaters and boilers, high-efficiency models, condensing units, and sealed venting boilers all cost more than basic gas boilers.
  • ZoningInstalling HVAC zoning costs $1,700 to $4,500 for room-by-room climate control.

Labor cost to fit a boiler

The labor cost of a new gas boiler fitted to existing connections is $1,000 to $3,500 on average, depending on the boiler type, location, and connection complexity. Replacing vents, pipes, and drains increases the total cost.

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Gas boiler running costs

Running a gas boiler costs $800 to $2,000 per year on average, depending on the home’s size, climate, local natural gas prices, and daily operating time. Heating with a gas boiler costs $1.00 to $1.40 per hour of usage.

Gas boiler running costs
Time frame Average cost to run
Monthly $65 – $165
Yearly $800 – $2,000

*Prices fluctuate according to local utility rates.

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Frequently asked questions

What is a gas boiler heating system?

A gas boiler heating system distributes boiling water through pipes to steam radiators, baseboard radiators, or radiant floor systems. Combi boilers also function as home water heaters. Boilers don’t need central air ducts because they don’t heat air like a furnace. 

How long to install a gas boiler

Replacing a gas boiler with an exact match takes 4 to 8 hours on average, while a new boiler installation takes 1 to 2 days. Changing the boiler type or moving it to a new location takes up to 3 days, depending on the plumbing and electrical modifications needed.

Gas boiler installation time
Install complexity Time
Replacement with same boiler type 4 – 8 hours
New boiler installation 1 – 2 days
Moving boiler to new location with new connections 1 – 2 days
Changing boiler type / fuel type 2 – 3 days

What is the lifespan of a gas boiler?

A gas boiler has a lifespan of 10 to 25 years on average. Cast-iron units, top brands, and high-efficiency models typically last longer with regular annual maintenance. Poorly maintained old boilers will decrease in efficiency every year.

Can a gas boiler be fitted in a bedroom?

Fitting a gas boiler in a bedroom is illegal according to building codes in most American states. Home boilers require installation inside an isolated room or closet enclosed with fire-resistant materials that typically has a separate outside entry.

Important: These installation precautions reduce fire hazards due to potential gas leaks and carbon monoxide poisoning.

Will a natural gas boiler run on propane?

Most natural gas boilers will run on propane with a conversion kit that costs $30 to $140 on average, excluding labor. A full conversion from natural gas to propane also requires capping natural gas lines and installing propane tanks onsite.

Can an oil-fired boiler be converted to natural gas?

An oil-fired boiler cannot convert to run on natural gas. Switching to natural gas heating requires replacing the old oil-fired boiler with a new gas boiler, replacing pipes, and removing the oil-storage tank.

Costs that may apply:

  • Installing a new gas boiler costs $3,200 to $9,000.
  • Oil tank removal costs $400 to $3,500.
  • New natural gas lines cost $12 to $25 per linear foot.
  • A new chimney liner costs $1,500 to $4,000.

Does a gas boiler use electricity?

A gas boiler uses 160 to 200 Watts of electricity for powering the:

  • Ignition
  • Thermostat connection
  • Display screens
  • Internal fan
  • Central heating pump

By comparison, a boiler’s power consumption is the equivalent of 2 to 4 lightbulbs, or less power than the average television or stereo receiver.

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Getting new gas boiler quotes

Before hiring a boiler installer near you, be sure to:

  • Choose HVAC professionals with certifications from:
  • Compare at least three new boiler estimates from experienced installers.
  • Select licensed, insured, and bonded HVAC contractors.
  • Avoid choosing the lowest gas boiler quotes that signal low-quality work.
  • Review their ratings on HomeGuide and Google.
  • Request copies of estimates, plan diagrams, heating-load calculations, equipment orders, permits, warranties, and contracts.
  • Verify the bids include material, labor, equipment costs, and the installation schedule.
  • Set up a payment schedule. Never pay in full upfront.

Questions to ask

  • What type of gas boiler do you recommend for my home, and why?
  • How long have you been installing boilers, and can I see references from past jobs?
  • Will you make a Manual J heat-load calculation to size my boiler?
  • Which kind of gas boiler and brands have you installed the most?
  • What’s the efficiency rating for this unit?
  • Does this boiler have zoning capabilities for room-by-room climate control?
  • Is this boiler compatible with my existing thermostat, or will I need extra wiring?
  • Are there any local boiler manufacturer rebates available for this model?
  • Will your estimate include removal and disposal of the old boiler? If not, how much extra will that cost?
  • Should I expect any additional costs?
  • Will you pull all the permits needed?
  • How long will the installation take?
  • What does the warranty cover, and how long does it last?
  • How can I extend the boiler’s lifespan?
  • Did the old boiler fail due to lime-scale buildup, and if so, how can I prevent it?
  • Do you offer a maintenance plan, and how much does it cost?
  • What’s your payment timeline?
  • Will you check the gas line connections for leaks?
  • What are the venting requirements for this boiler according to building codes?

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