Boiler or Furnace?

Jurgen Beneke
5 days ago
2 min read

A Quick Guide for First-Time Homebuyers

If you’re house hunting for the first time, it can sometimes feel like you’ve wandered into a foreign film:

boiler, furnace, heat pump, air handler, heat exchanger…

real estate agent showing a boiler and expansion tank

Say what?

No subtitles.

All of a sudden there’s a whole vocabulary being thrown at you in the basement of a house, and everyone else seems to understand it. Meanwhile you’re standing there nodding politely, hoping no one asks you a follow-up question.

Today I want to explain two of the most important and frequently used words when it comes to heating systems:

Boiler or furnace. What’s the difference?

Now, I know a lot of the guys out there are thinking, “I know exactly what this is—no need to tell me.” But trust me, even seasoned pros in the real estate business mix these terms up. So let’s run through it quickly. This should take about a minute, and you’ll be clear on the difference.

The Short Version

One makes hot water or steam. The other blows hot air.

Boilers

To make hot water or steam, what do you have to do?

You boil it.

That’s your hint.

So whenever you see a heating system with:

Radiators
Hydronic baseboards
Radiant floor heating
Steam radiators

…it’s almost always connected to a boiler.

A boiler heats water inside a closed system. That hot water (or steam) travels through pipes to radiators, baseboards, or tubing in the floor, where the heat radiates into the room.

Furnaces

On the other hand, if the house has forced-air heating, the system needs to heat up air, not water.

How does it do that?

Fuel is burned inside the furnace, and that combustion heats a component called the heat exchanger. Air from the house is blown across the heat exchanger, warms up, and then gets pushed through ductwork to the rooms in the house.

So that system is called a furnace.