Furnace vs Boiler: Which Is Right For Your Home?

Furnace vs boiler heating
Find out the main difference between furnace and boiler. How can you figure out which type of heating system will save you the most money and provide the most comfort?

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

The truth is, there are pros and cons to each heating system. It is best to research both to decide which one fits your personal preferences and budget. For example – boiler heat is more evenly distributed throughout your home, but furnace heat can be combined with central air AC (no need to pay extra for duct work).

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

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

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Basic Difference Between Furnace and Boiler

The biggest difference between furnace and boiler is that a furnace uses air to transfer heat throughout your house, whereas a boiler uses water.

Hot Water 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.

Forced Air Heating System

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

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A forced air heating system consists of a furnace and a system of ducts to circulate the air. The system works by drawing the air in the room into the ductwork and which deliver it to the furnace, where the air is filtered and heated. The warm air is then circulated 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.

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

Heating Comfort: Difference Between Furnace and Boiler

Heating System Comfort

When it comes to heating, the most important thing we expect is comfort. This is especially true in colder climates, where the worst nightmare of every homeowner is to wake up in freezing cold. Maintaining comfortable temperatures throughout the house is especially important for families with older people or small children, because both are very sensitive to temperature fluctuations.

It turns out that there is a comfort difference between furnace and boiler.

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

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%

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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Cost Difference Between Furnace and Boiler

Many homeowners opt for a 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.

There are many gas furnace models that cost in the range of $600-1,000, while most gas boilers cost $1,500+. Similarly, an oil furnace costs between $1,000-1,600, where as an oil boiler costs between $2,000-5,000. Most electric furnaces cost under $500, but they are not very efficient, so most people don’t use them.

On average, installation costs are also cheaper for furnaces. You can expect to pay an average of $1,200-2,500 for a gas furnace replacement. Replacing an oil furnace is a lot more expensive, and runs in the range of $4,000-5,5000. By comparison, on average replacing a gas boiler costs between $3,5000-8,000, and replacing an oil boiler costs between $3,000-5,000.

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

Heating Bills and Energy Efficiency

Heating costs of boiler vs furnace

When comparing the difference between furnace and boiler models for energy efficiency, they are about the same. Many new models of both furnaces and boilers have over 95% energy efficiency.

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

If you have an older furnace or boiler system, your energy efficiency is 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 can consider retrofitting your existing system to make it more energy efficient. Changes may include replacing your old boiler of furnace with a high-efficiency model, upgrading ductwork in forced-air system or adding zone control in a hot-water system, and installing programmable thermostats.

Longevity and Maintenance

When it comes to longevity, both furnaces and boilers last an average of 15-20 years. With regular maintenance, both devices can last even longer.

However, a furnace requires more maintenance and is more susceptible to breaking and requiring service than a boiler. A boiler requires an annual inspection and virtually no maintenance, if its working properly. A furnace requires regular filter replacements, anywhere from 1-4 months, depending on the quality of the furnace 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 job 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 boilers/hydronic heating systems

While a hydronic heating system provides a lot more comfort and convenience, there are two serious drawbacks, that prevent most people from switching or installing it in the first place. The first is the high cost, especially if one wants 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.

The second major disadvantage is that a hot water heating system will not provide air conditioning in the summer. This means that a separate central air system would need to be installed, which can very expensive, 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 Heating Systems for individual rooms

If you have a room / space in your house (as an addition that was an after thought and not properly designed), or a stand-alone heated guest house / garage, where there is not enough heat, or it’s problematic to run duct-work or baseboards in said room, you can install a Ductless HVAC system that can heat/cool up-to 500 sq. ft. and not be tied with your main heating/cooling system.

Ductless (mini-split) HVAC works on 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.

To explain how efficient they are – late models Nissan Leaf electric vehicles, as well as Tesla EVs now come with heat-pump heater, and get extra 10-15 miles on a single charge in the winter (compared to traditional heater used in older models). Newer high end Motorhomes / RVs now also come with a Heat Pump option/upgrades, to provide more energy efficient heating and cooling. In both examples not only energy cost is a concern, but also AMOUNT of energy available, since both EVs and Motorhomes/RVs have a very limited amount of electricity to operate these power hungry HVAC systems.

Here is more info on benefits and costs of Ductless HVAC systems.

DuctLess HVAC (Mini-Split) system costs
1 Room
$2900 - $3800
2 Rooms
$6000 - $7800
3 Rooms

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