Explaining the Difference Between a Boiler and Furnace

San Rafael

(415) 942-6565

Santa Rosa

(707) 452-3464

With fall and winter coming upon us, you might be wondering how your house is able to stay so warm. Well, most homes come equipped with a central heating system but many people aren’t familiar with the parts that make up that system or how it functions. Getting to know these different components can help you in the event of a malfunction. Nothing would be worse than waking up and feeling like you have frostbite. Now, we know that California doesn’t experience extremely cold weather like other parts of the country but boilers and furnaces are still essential to our homes. Let’s take a look at the two and how they operate to provide warmth and comfort.


Boilers distribute heated water or steam through small pipes to your radiant heating system, which generally heats homes through piping underneath the flooring. Fun fact: there’s radiant heating in the floor of the elephant house at the San Francisco Zoo!

How Does A Boiler Work?

  • Your thermostat senses a drop in temperature and calls for the boiler to turn on.
  • The boiler will power up and use oil, gas, or electricity to heat water.
  • The hot water or steam will be distributed throughout your home through radiators or radiant floor systems.
  • As the water cools down or steam condenses, it will travel back to the boiler.


Furnaces are fueled by gas, oil, or electricity to heat a series of coils which then pushes air out through a forced-air system. Heat is then distributed throughout your home’s duct system.

How Does A Furnace Work?

  • Your thermostat is activated and calls for heat from your furnace
  • Gas or propane is ignited in the furnace’s burner
  • The flames heat up a metal heat exchanger
  • The heat exchanger transfers to the incoming air
  • The furnace’s blower pushes that heated air into the ductwork throughout your home
  • Once the warm air is distributed, the cold air retreats back into the furnace

Different types

Boilers and furnaces come in three different forms: gas, oil, and electric. While they work differently, they share these things in common:

  • Gas– The most common type and are typically cheaper to install and operate.
  • Oil– While they aren’t as eco-friendly, they can sometimes work more efficiently if natural gas is unavailable.
  • Electric– Rather than burning fuel, it uses electrical power to heat. While they’re more “clean,” they’re not as efficient and cost more.

How to tell the difference

Central heating systems can be complex; but, in simple terms, a boiler heats a home with hot water while furnaces heat air. Another differentiating factor is the way heat is dispersed. Boilers distribute fluid through pipes and furnaces use air ducts. Are you interested in knowing which system is installed in your home? One telltale sign of boilers is if your home has radiators. Another way to tell is if your heating system has piping or tubing attached to it. On the other hand, furnaces will be connected to ductwork and typically extend up to your ceiling.

Which is better?

Each system has its pros and cons, just like anything else, and you’ll find convincing arguments for both sides. Boilers tend to produce cleaner heat and have lower maintenance costs. Additionally, they can be more energy efficient, allowing you to save on your utility bill. However, the problem with boilers is they can take a while to warm a room and raise humidity levels. Furnaces are great because they are less expensive and easier to install.

If you’re interested in expert advice on which system is right for your home, contact John Owens Services online or give us a call. We are the furnace repair & replacement specialists in Sonoma & Marin counties, with locations in Santa Rosa & San Rafael!

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San Rafael
(415) 942-6565
Santa Rosa
(707) 452-3464



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San Rafael
(415) 942-6565
Santa Rosa
(707) 452-3464