What is the Difference Between a Boiler and a Furnace?


There are a lot of words that we tend to use interchangeably: “Cellar” and “basement.” “Brook” and “creek.” “Sofa” and “couch.”

But here’s two terms that you won’t hear us confuse: “furnace” and “boiler.”

True, they both heat your home, but there are important distinctions separating these systems. In this week’s blog post, we’ll look at the difference between a boiler and a furnace.

Furnace-VS-Boiler-GraphicWhat is a furnace?

They key difference between a furnace and a boiler is that one uses air while the other uses water.

A furnace is the heating unit inside a forced air system. It can be powered by electricity, oil, propane or natural gas. It heats air, which is then sent throughout a building through ducts. 

What is a boiler?

Like a furnace, a boiler can be powered by a few different energy sources, including electricity, gas and oil. A boiler heats water with a combustion chamber, and then pumps that water through pipes into radiators to heat a building.

What are the pros and cons of using a furnace?


There are several advantages to installing a furnace, including:

  • They are more common than boilers, and thus less expensive. A new furnace can often cost half of what you’d pay for a boiler.
  • Furnaces are easy to install. The process takes a few hours, while putting in a new boiler can take a few days.
  • If a furnace leaks, it will leak air, while a leaky boiler can subject your home to water damage.

The drawbacks of having a furnace include:

  • Furnaces are less efficient than boilers, which could mean higher energy costs.
  • They make noise every time they switch on and offer less consistent heating, which means some rooms might be warmer or cooler than others.
  • Because furnaces circulate hot air, they also blow out dust and allergens, and can make the air in your home drier during the winter. Though a whole home air purifier, like the Air Scrubber Plus® device can help clean the air. Once it’s in place, you’ll ensure that virtually every surface is cleaner and safer for your family, from air ducts to furniture to countertops to doorknobs. It’s as simple as turning on your fan, furnace, or air conditioning system.

What are the pros and cons of using a boiler?

BoilerJust like a furnace, a boiler comes with its own benefits and drawbacks. For example:

  • Boilers use less fuel than furnaces, which means you could see lower energy bills.
  • They provide a more consistent heat, and less operational noise. They also require less maintenance than a furnace.
  • Unlike furnaces, boilers don’t blow air and therefore don’t dry out the air in your home or spread allergens, leading to better air quality.

However, installing a boiler has its downsides:

  • They are harder to install than furnaces, and difficult to convert from a forced air system. If you need to cool your home, you can’t rely on your boiler the way you could a forced air system.
  • Boilers take some time to respond to thermostat adjustments, which means it will take longer for your home to feel warmer or cooler.
  • And as we noted above, a leak in your boiler can lead to water damage in your home.

Now that we’ve outlined the difference between a boiler and a furnace, we should note the one thing they – and any HVAC system – have in common: they all require routine maintenance.

By making sure your heating system undergoes regular maintenance and cleaning, you can prevent serious problems from surfacing down the road.

Is it time for your HVAC unit’s regular checkup? Contact All Seasons Comfort Control. Whether you have a furnace or a boiler, we can inspect your system to make sure it’s providing you with the comfort you and your family need. If you’re in need of a new boiler or furnace, we can help with that too.