How Much Do Gas Boilers Cost?

Typical Range:

$3,290 - $8,458

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Cost data is based on actual project costs as reported by 967 HomeAdvisor members. Embed this data

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  • We compile the data and report costs back to you.

Updated December 12, 2022

Written by HomeAdvisor.

Gas boilers cost $5,845 on average, or typically between $3,290 and $8,458. Price depends on efficiency, output, and brand. A gas boiler heats water for hydronic radiant heating systems such as traditional radiators or in-floor heating. Some combination systems provide both heat and hot water. They use natural gas, propane, and even butane, depending on what is available near your home, with natural gas being the least expensive option when available.

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National Average $5,845
Typical Range $3,290 - $8,458
Low End - High End $580 - $12,000

Cost data is based on actual project costs as reported by 967 HomeAdvisor members.

High-Efficiency Gas Boiler Prices by AFUE

Although gas boilers typically run between $3,290 and $8,458, you’ll pay 50% more for higher efficiency models. But you’ll likely make up much of that in fuel savings over the years. Most units have an efficiency measured in AFUE.

While most boilers have a rating of 81% to 87%, it’s good to understand what manufacturers and the EPA mean when they say “high efficiency.” These numbers do not include energy lost to leaky ducts in attics, garages, crawl spaces, or units outside the home. 

  • Older low-efficiency models run about 50%–70% AFUE. You won’t find any new units with this low of a rating.

  • Standard (moderate efficiency) models are 80%–85% AFUE.

  • High-efficiency models run 90%–98.5%.

Gas Boiler AFUE PercentUnit Price*
80-85$2,000 – $7,500
90-98.5$3,500 – $10,500+

*Does not include labor costs needed to install it. 

What Is AFUE?

AFUE stands for Annual Fuel Utilization Efficiency. While BTUs are a measure of how much heat the unit produces (which we get into later), AFUE is a measure of how efficient the unit is in using the fuel to create BTUs. 

AFUE is a measure of the percentage of fuel used when you compare input to output. For example, if you buy a model with 82% AFUE, this means that 82% of the gas gets converted into heat energy. Higher-efficiency furnaces deliver the same BTU output with less fuel use than a lower-efficiency model.

Energy Star Gas Boilers

The EPA no longer awards the energy star designation for gas boilers, although, classically, they awarded it to boilers with a 90% or higher efficiency. Electric boiler installation costs tend to be lower, and the models tend to have a nearly 100% fuel efficiency rating. However, the cost of electricity is generally higher than natural gas. So, while electric units are more environmentally friendly, they’re generally not as economical to run.

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Residential Gas Boiler Prices by Brand

Although gas boilers typically run between $3,290 and $8,458, they’ll vary a bit by brand. Many companies produce appliances of various types. Here are several top manufacturers of residential gas boilers, along with pricing on popular models.


Weil-Mclain gas boilers tend to range from $2,000 to $10,000 for residential boilers. They also create commercial boilers that cost $12,000 to $53,000. In business for more than 125 years, Weil-McLain offers an extensive line of gas boilers for residential and commercial use.

Gas Boiler Model SeriesPriceAFUE Percent
Aqua Balance Series 2 (80 to 155K BTUs)$2,000 – $2,50095%
CGa Series 3 (38 to 233K BTUs)$2,000 – $4,00095%
Evergreen Series (110 to 399K BTUs)$3,500 – $9,50095%
ECOTec Series (80 to 199K BTUs)$3,000 – $5,50095%
CGi Series 4 (48 to 222K BTUs)$2,000 – $4,500Up to 84%
EG Series 6 (75 to 282K BTUs)$2,000 – $5,000Up to 84%

Other Major Brand Prices

Many manufacturers produce boilers for residential use. Other common brands include:

  • Westinghouse: $2,000–$3,500

  • Triangle Tube: $2,100–$8,700

  • Utica: $2,000–$6,000

Residential Gas Boilers Prices by Size

Gas boilers cost $2,000 to $10,000, in part related to output. When you choose a product, you'll start by considering the size you need. Size may refer to the appliance's dimensions and output, typically measured in BTUs. Another size you may end up seeing is MBH, which is 1,000 BTU’s per hour. 

Gas Boiler BTUsUnit Price
<100,000$2,000 – $5,000
100,000-150,000$3,000 – $7,000
150,000+$3,000 – $10,500

What Are BTUs?

Most residential gas boilers range from 44,000 to 300,000 BTUs in heating output. Boilers measure output in British Thermal Units (BTUs). One BTU is how much energy is required to raise one pound of water by one degree Fahrenheit. 

  • You may see units with an output of 400,000 or more BTUs. These are generally designed for commercial or industrial use.

  • Keep in mind that each appliance lists BTUs for input and output. A unit with 100,000 BTUs input and 95% AFUE would have an output of 95,000 BTUs.

  • You may also see an “MBH” rating, which is simply 1,000 BTU/hour.

How to Choose a Gas Boiler

You can get a rough estimate of the output in BTUs you need based on your climate and the square footage of your house:

  • Cold Climate/Older Home: 50 BTUs per square foot

  • Moderate Climate/Newer House: 35 BTUs per square foot

  • Hot Climate: 20 BTUs per square foot

For example, a 2,500-square-foot-house in a cold climate needs one with an output of at least 125,000 BTUs. Remember that the output you need depends on a lot of factors, like insulation and the age of your home. Talk to a pro to get an accurate estimate for your home's heating load.

Wall-Mounted Gas Boilers

Dimensions and location also affect the type of boiler you choose. Many wall-mounted options are only about six inches thick. This means that even if you decide to hide it in your hall closet, it's not going to take up much room. Installing it in places like the kitchen or laundry room makes it easier to access for routine maintenance.

Gas Boiler Costs by Type

You’ll have two main options for a boiler: a standard variety that just heats water for the home, or a combi boiler that provides both home heat and hot water for use in bathrooms and kitchens. 

  • Standard boilers cost $4,500 on average, including all installation costs. 

  • Combi boilers cost $7,000 on average, including all installation costs. 

Gas Boiler Installation

The cost to install a boiler runs from $1,000 to $3,500, depending on whether it’s a direct replacement or if you need to have new lines run or modifications to your home to make it fit. The total depends on the price of the unit, as well as the labor needed to remove and replace.

Additional Cost Considerations

On top of the cost of the gas boiler and installation, you may need to add $1,000 to $10,000 to the final price. These depend on your location and the kind of heating system you had previously. For example, if you have an oil-fired system, you’ll want the old oil tank removed. Replacing electric with gas means running a gas line to the new location. 


Permit prices typically range from $50 to $300, depending on where you live. Research your local government's rules for utilities to find out how much you'll need to pay.

Removal of Old Oil Tank

Oil tank removal costs $500 to $2,000. If you're converting to natural gas from oil, you may need to pay for this service to remove and dispose of the old tank.

Local Gas Steam Boiler Price & Companies

Buying or replacing a boiler is a complicated project that requires a professional. Not only for installation, but also for maintenance. Boiler repairs cost$200 to $650. Local gas boiler companies have the best estimates for prices in your area and any factors that might affect installation. 

DIY vs. Hiring a Gas Boiler Installer

Because gas is involved in installing a gas boiler, it’s best to have a professional do the work. In most places, the homeowner is technically allowed to install a gas line. However, always have it inspected by a professional; improper installation is both dangerous and can lead to home damage, which usually isn’t covered by insurance if done yourself. Finding a local boiler installer is the safest and fastest way to get the job done.

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How long do gas boilers last?

Gas boilers have a life expectancy of 10 to 30 years, depending on type and upkeep. Cast iron models are less efficient but tend to last longer. There are boilers over 50 years old as well. The largest factor in how long a boiler lasts tends to be how corrosive the water in the home is. Proper yearly inspections and maintenance to clean them out of any debris and inspect for leaks can extend their lifespan.

How do steam boilers work?

A gas steam boiler uses gas to heat a series of pipes that run through water. This creates steam, which then travels through pipes to radiant appliances, like a radiator or baseboard radiant system. As the vapor cools, it turns back into liquid and returns to the appliance, and the cycle repeats. These are used primarily to heat a home.

Is a furnace the same as a boiler?

Furnaces and boilers are not the same things. A furnace uses gas or electricity much in the same way as a boiler. However, in a furnace, air passes over heated coils with a blower, which pushes the air through the home. Cold air goes through an air return duct. 

A boiler works similarly, but instead of air, it pushes water. The water in turn travels to radiant heaters in the home (baseboard, in-floor, or radiators). As the water cools, it condenses and travels back to the boiler.

Is it cheaper to heat with propane or electric?

While installing an electric boiler costs less than propane, the price you pay for heating depends on your region and the season. Electric units usually have an AFUE of 99% to 100%, but energy bills may be higher. However, with rising and fluctuating gas prices, the price gap changes. It’s best to talk to your local boiler installer or HVAC professional and see if there are incentives or other deals for installing electric versus gas before you choose which one to go with.

Will a natural gas boiler run on propane?

A natural gas boiler will almost always run on propane with some slight modifications. You can usually get a conversion kit, which adapts the furnace to the different characteristics and pressures between the two gasses. It’s almost always a good idea to have a professional do this work for you rather than trying to do it yourself. This usually requires hiring a boiler repair company near you.