Furnace vs Boiler: Installation Costs, Efficiency, Pros & Cons

The two most popular ways to heat a home are using a home furnace or a boiler. Each system has its own pros and cons, as well as costs associated with installation and maintenance.

Let’s compare the main differences between a boiler vs furnace. Find out which of these two heating systems offers the greatest efficiency, energy savings and most comfort.



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

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Furnace vs Boiler – what is the main difference?

Heating Furnace = Forced Hot Air + Ducts.

Hot Water Boiler = Forced Hot Water + Baseboards / Radiators.

A furnace uses air to transfer heat throughout your house, whereas a boiler uses water. This is the biggest difference between these systems.

When it comes to comfort, 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).

How does a furnace work?

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 uses electricity, natural gas or heating oil for fuel. Gas furnaces are most common, especially in areas with very cold winters. Read our guide on how to pick the right furnace and enjoy the highest energy efficiency.



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

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How does a boiler work?

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.

If you already have hydronic heat, but want to add more warmth to specific areas in your house, consider installing radiant sub-floor heating.



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 / bacteria / etc, that may and does collect in ducts, in your basement, and on furnace air filters!

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%

Installation cost differences

Many people opt for a home furnace because it is significantly cheaper than a boiler. 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.

The average price for a gas furnace is $600-1,000, while gas boiler prices for most models 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 vs 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, installing a boiler costs more. A new gas boiler 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).



Cost of heat 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

Get a free estimate to replace your heating system from a local HVAC pro.

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 work well even longer.

However, a furnace requires more maintenance. It is more susceptible to breaking and needing more frequent professional repair services than a boiler. 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.

For best functionality, a boiler should get an annual inspection. If it works properly, there is virtually no maintenance involved.
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.



Boiler pros and cons

Here are the main advantages that a boiler offers:

– Uses less fuel to heat your home. This leads to greater savings on energy costs as well as improved efficiency.
– More pleasant, evenly distributed heat
– Very quiet operation. You cannot hear when the boiler is working.

Disadvantages

While a hydronic heating system provides a lot more comfort and convenience, there are two serious drawbacks, which 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.

Another minor con to keep in mind is that a boiler takes longer than a furnace to adjust to thermostat changes. This means it will take you longer to feel a temperature change in the room after you have turned the heat up or down.

Furnace pros and cons

The biggest advantage of a furnace is its relatively low cost compared to installing a boiler system. For most people this can be the deciding factor when choosing a heating system. Typically you can save as much as 50-60% off the cost of furnace compared to a boiler.

Installation is also much quicker and easier. It can take a few hours to install a furnace, compared to a few days to install a boiler. This time difference also contributes to reduced labor costs to installing a furnace.

Another pro is that there is no risk of having a hot water leak, as is the case with a boiler. These leaks can cause thousands of dollars in damages and can be difficult to repair. With a furnace, you will not have to worry about this at all.

If you live in a cold climate, you don’t run the risk of having a furnace freeze if the power goes out. This problem exists with a boiler.

To summarize the cons that we have already discussed, furnace heating poses the following issues:

– Less energy efficient
– Poor air quality and potential allergic reactions
– More noisy than a boiler
– Inconsistent heat. You may find that some rooms in your home are warmer than others.

Alternative types of heating

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

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



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: Installation Costs, Efficiency, Pros & Cons

  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.

    Reply