Furnace vs Boiler: Which Is Right For Your Home?

In this post, we will compare the main differences between a home furnace and a boiler. Find out which of these two heating systems offers the greatest efficiency, energy savings and most comfort.

Heating Furnace = Forced Hot Air + Ducts.
Hot Water Boiler = Forced Hot Water + Baseboards / Radiators.

Forced Hot Water Boiler Costs
Gas Boiler
$3900 - $5600
Oil Boiler
$4800 - $6700
Base Boards
$2100 - $3500

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A furnace uses air to transfer heat throughout your house, whereas a boiler uses water. This is the biggest difference between these systems. Naturally, each one has its pros and cons. For example -boiler heat is more evenly distributed throughout your home. However, furnace heat can be combined with Central Air (no need to pay extra for duct work).

Lets take a look at what each type of heating has to offer and how much it costs.

forced air vs central air

Hot Water Boiler (radiator heating system)

Using water for heating is called a radiator or hydronic heating system. It consists of a hot water boiler, baseboard, circulator pump, system of pipes and radiators that are distributed throughout various rooms of the house.

A boiler heats up the water, and then either a circulator pump or zone valves distribute it through a system of pipes into radiators, which are located throughout the house. As the hot water passes, it gives off heat. Once the water cools down, it circulates back to the boiler to be reheated.

Boilers typically use gas, propane or oil for fuel.

PRO TIP: Natural gas boiler is by far the most cost efficient way to heat your home in the US (rivaled only by high-efficiency ductless heat pumps). Even with relatively low oil prices over the last decade (since 2008), natural gas is still way more economical than heating oil. The reason for this is utter inefficiency in how oil is sprayed into the burner, to keep the flame going, while heating the water.

Forced Hot Water Boiler Costs
Gas Boiler
$3900 - $5600
Oil Boiler
$4800 - $6700
Base Boards
$2100 - $3500

See costs in your area Start Here - Enter Your Zip Code

In the equally well insulated home, oil will typically cost 40-75% more than natural gas, even with price fluctuations, over a period of 5+ years!

Therefore, if you have a choice, we recommend to always go for a radiant heat + gas boiler over hot air furnace.

Besides pure operating cost factors, the warm air from radiators is NOT DRY, like that from ducts, and does not contain dust / allergens / bacterias / etc, that may and does collect in ducts, in your basement, and on furnace air filters!

Forced Hot Air Furnace (air duct heating)

Forced air heating consists of a furnace and a system of ducts to circulate the warm air. The cool air in the room is drawn into the ductwork, which delivers it to the furnace. Here, the air is filtered, heated, and then circulates back into the room via a different duct system.

Furnaces are available in three different designs: “upflow,” “downflow” and “horizontal” models. These can accommodate different types of set up requirements, such as basement, attic or another limited space installation.

A forced-air system can be combined with a humidifier and an air filter, to improve air quality. This can be particularly important if someone in your household has asthma or allergies.

A furnace typically uses electricity, natural gas or heating oil for fuel. Gas furnaces are most common, especially in areas with very cold winters.

Forced Hot Air Furnace Costs
Low End
$3900 - $4500
Mid Range
$4500 - $5500
High Efficiency
$5900 - $7100

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Which offers the most comfort?

baseboard heating vs forced air

When it comes to heating, the most important thing we expect is to have reliable warmth that is evenly distributed throughout the house. This is particularly true in colder climates, where the worst nightmare of every homeowner is to wake up in freezing cold. Maintaining consistent room temperature is especially important for families with older people or small children, because both are very sensitive to hot/cold fluctuations.

Here is a comparison chart of the comfort and convenience you can expect from a boiler vs a furnace.

Hot Water Heating (boiler) Forced Air Heating (furnace)
Heat Distribution Even throughout the room Fluctuates, depending on location of ducts
Temperature consistency Even, no cold spots May vary, there may be cold spots in different parts of the house
Noise Level Silent Varies depending on the quality of the furnace, but is never completely silent
Humidity Normal Air can become very dry and a humidifier may be needed
Air Quality Clean May contain dust and other allergens. To maintain good air quality, ducts need to be regularly cleaned and filters need to be regularly changed.
Air Drafts None Frequent
Heat Zones Numerous heat zones can be established throughout the house to achieve even heating Difficult to establish zoning. Maximum of three different zones is possible and requires complex ductwork installation
Radiant Floor Heating Can be easily installed Not possible to install
Safety Completely safe Child may stick hands or objects inside the vent
Heat Loss None Yes, up to 35%

Cost Differences

Many people opt for a home furnace because it is significantly cheaper than a boiler. Both the cost of the device itself and installation are 2-3 times more expensive for a boiler than for a furnace of comparable size and efficiency.

Average gas furnace cost is $600-1,000, while prices for most gas boilers start at $1,500+.

Similarly, an oil furnace runs between $1,000-1,600, where as an oil boiler costs between $2,000-5,000. Many electric furnaces cost under $500, but they are not very efficient, so most people don’t use them.

On average, it is also much cheaper to install a furnace compared to a boiler. Typical gas furnace replacement cost is about $1,200-2,500. Replacing an oil furnace is a lot more expensive, and runs in the range of $4,000-5,5000. Still, replacing a boiler is a lot more expensive. A new gas boiler install is $3,5000-8,000, while an oil boiler costs $3,000-5,000.

(note, these are general price estimates for straightforward installs that don’t require any additional complex work).

Heating bills and energy efficiency

Heating costs of boiler vs furnace

When it comes to energy efficiency, it turns out that both systems are about the same. Many new models of furnaces and boilers boast over 95% energy efficiency.

However, it still costs more to heat with a furnace and is less efficient, particularly in areas with very cold temperatures. This happens because a lot of the heat that the furnace generates, escapes through the ducts system and gets lost. This happens most if the ducts are located in a partially conditioned or unconditioned space, such as an attic, basement or a garage. The heat loss can be as high as 35%, which can significantly increase your heating bills. Hydronic systems that use a hot water boiler don’t have this problem.

However, if you have an old system, regardless of whether its a boiler or a furnace, your energy efficiency will be very low, only about 50-65%. This means that you are wasting both fuel and money to heat your house. If this is the case, you should consider retrofitting your existing system to make it more energy efficient. Changes may include:

– replacing your old boiler or furnace with a high-efficiency model
– upgrading ductwork in a forced-air system
– adding zone control in a hot-water system
– installing programmable thermostats

Longevity and maintenance

When it comes to longevity, both a boiler and a furnace last about 15-20 years. With regular maintenance, both devices can last even longer.

However, a furnace requires more maintenance. It is more susceptible to breaking and requiring frequent repair service than a boiler. Usually, a boiler needs an annual inspection and virtually no maintenance, if its working properly. With a furnace, you need to deal with regular filter replacements, anywhere from 1-4 months, depending on the quality of the device and filters. Ductwork may also require cleaning.

Because a boiler does not have many moving, mechanical parts, the main thing that can go wrong with it is the circulator pump will break. This happens rarely and can be easily fixed. A boiler repair costs between $300-500.

By comparison, a furnace has a blower fan and a motor to push the air through, which can stop working. Because these are mechanical parts that are constantly moving, they are more susceptible to breakage. An average repair job for a furnace is similar to a boiler, also about $300-500. It costs about $250 to replace a furnace thermostat.

Main disadvantages of a hot water boiler

While a hydronic heating system provides a lot more comfort and convenience, there are two serious drawbacks, that prevent most people from switching to it or installing it in the first place.

1. Very high cost, especially if you want to make the switch from an existing forced air system to hydronic. For most homeowners spending thousands of dollars is not worth it, if their furnace is working well and they have a good ductwork system already in place.

2. No air conditioning in the summer. This means that a separate central air system would need to be installed, which can be very expensive. The cost is at least $10,000-15,000+, if the home does not have a duct system in place.

However, people that can afford it create an ideal setup, which includes both systems. This way they reap all the benefits: enjoy central air cooling in the summer and hot water heat in the winter.

Alternative types of heating systems for individual rooms

One of the most popular alternative sources of heat that many homeowners install is a ductless mini split. It is usually used in the following situations:

– there is a room or addition that was poorly designed and doesn’t get heated by the main system
– you build an addition after installing the original heating system so it needs its own source of heat
– you have a stand-alone guest house / garage, where there is not enough heat
– it’s problematic and/or too expensive to run duct-work or baseboards in the spaces described above

A ductless HVAC system that can heat and cool up-to 500 sq. ft. and not be tied with your main heating/cooling system. It works on the heat-pump principal and is much more efficient than traditional “electric” fired heating/ cooling sources. And yes – mini-splits produce both HOT and COLD air. Total cost ranges from $1,900-3,000.

Another great option is to install electric under floor heating. These electric mats are very easy and fast to put in to any space that needs some additional heat. They are most often used in a bathroom, kitchen, or a home addition. The price of an electric radiant floor mat for an 8×10 space is about $800-1,000.

Forced Hot Air Furnace Costs (1800 sq. ft. home)
Central AC
$3600 - $4500
Hot Air Furnace
$4500 - $5900
Central Air + Ducts
$11900 - $16100

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About Yelena G

Yelena G. has been working in the remodeling and construction industry for over 15 years. Her focus is on construction planning and design as well as project cost estimating. Yelena also has a personal interest in interior design, as well as in unique DIY remodeling projects. Read more about Yelena

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One thought on “Furnace vs Boiler: Which Is Right For Your Home?

  1. Deb Pearl

    That is really nice that boiler works by heating up water and circulates it through pipes throughout the house. My husband and I have been trying to decide if we want a boiler heating system or a furnace. Thank you for comparing the two. This is a huge help.