Boiler vs Furnace: What’s the Difference?

Your home includes a number of systems that make life more comfortable. There’s air conditioning for cool air and humidity control in the summer months. There’s a water heater so you can enjoy a hot shower or bath. And when it comes to heating your home, you might rely on a furnace, boiler, heat pump, or geothermal system. Looking more specifically at boilers and furnaces, many people use these words interchangeably. While it’s true they both heat your home, it's important to know that they are quite different in how they do it. For more detailed information about Carrier furnaces and boilers, visit our residential products website. Or, read on for a boiler vs furnace comparison.

In the most basic terms, a furnace heats air, which is then distributed to your living areas through a series of ductwork and vents. A water or steam boiler pipes hot water or steam to radiator units in your living areas to heat your home. Understanding the furnace vs boiler difference can help you make the best decision for heating your home.

Boilers vs Furnaces: How Do They Work?

Most modern boilers use either natural gas or oil as a fuel source. A boiler heats water to create steam or hot water. That steam or hot water travels through pipes into radiators throughout the home, such as radiant flooring systems or baseboard radiators. Rooms in your home are radiantly heated without using fans or ductwork.

Natural gas, propane, oil and electric furnaces heat the air in your home using combustion or electricity to warm up a heat exchanger or heating element. A strong fan pulls air into the furnace, across the heat exchanger or heating element, and then distributes the warmed air into your living areas through the home’s duct system and vents or registers.

Maintenance Requirements

For prolonged life expectancy and maximum efficiency, all heating systems should be maintained annually. A professional maintenance visit from your local HVAC dealer might include inspecting vent systems, fuel lines, and heat exchangers for signs of leakage or material degradation in addition to cleaning and lubricating critical components. Find a Carrier dealer to set up a maintenance schedule appropriate for your system.

Because a boiler heats without using forced air, it tends to require less month-to-month maintenance than a furnace that requires routine air filter inspections or replacement every 30 – 90 days. Most homeowners can easily do this themselves. If you want to learn more about how to maintain and service your home furnace, check out our furnace maintenance web page.

Boiler vs Furnace Monthly Costs

In many cases, the upfront cost of a new furnace with installation can be lower than it is with boilers. However, making a generalized boiler vs furnace monthly cost comparison for heating your home is challenging.

Both types of heating systems offer energy efficient models. Looking at Carrier heating products, our gas boilers offer up to 95% AFUE efficiency. Our highest efficiency gas furnace heats your home with up to 98.5% AFUE efficiency, and we have several models rated at 96% AFUE. While published ratings for furnaces and boilers can be similar, the actual cost to heat your home can be quite different. Fuel costs can vary from region to region, especially when you compare natural gas vs fuel oil. The amount of fuel needed will also vary depending upon the temperature you keep your home, the type of thermostat you use, how well your home is insulated and more.

The Best Choice for Your Home

If you are replacing an existing system, the easiest choice is often sticking with what’s already in place. However, this may also be a good time to consider making a change. Making the best choice for your home starts with understanding furnace vs boiler differences and the pros and cons of each.

Here are some similarities and differences:

Comparing Boilers and Furnaces

	Boiler	Furnace
Comfort	Radiant heating, requires separate cooling system	Forced air heating, often combined with central air
Cost	Usually more upfront cost	Usually less upfront cost
Energy Efficiency	Up to 95% AFUE	Up to 98.5% AFUE
Fuel Source	Natural gas, fuel oil, propane, electricity, wood pellets	Natural gas, propane, oil, electricity
Indoor Air Quality	Doesn’t circulate airborne pollutants	Circulates airborne pollutants through air filter
Ductwork	No	Yes
Radiators	Anywhere heat is desired	No
Water/steam piping	Yes	No

Boiler Pros and Cons

Boilers offer a number of advantages for heating your home, including draft-free radiant heat, less overall maintenance, and reduced circulation of airborne pollutants in your home because it’s not a forced air system. On the downside, boilers cost a little more upfront (typically), often take more time for installation and setup, and have the potential for repair costs associated with leaking or freezing water pipes.

Furnace Pros and Cons

Furnaces are the more commonly used heating systems; typically cost a little less upfront; often take less time to install; and are frequently paired with an air conditioner as part of a complete heating and cooling system.