10 Surprising Furnace Facts


As the temperatures drop, most of us are ready to spend less time outdoors and more time inside where it’s cozy and warm. Thanks to our furnaces, we’re able to do just that.

Here are 10 facts you might not know about furnaces, including where the name “furnace” comes from.

1. Furnaces are the most popular way to heat homes (and for good reason!)

The majority of homes in the United States are heated by furnaces. This method of heating warms the house by sending air through a system of ducts found in the floors, walls and ceiling ducts. Energy sources for furnaces include natural gas, oil and electricity, or sometimes a combination. Natural gas systems are the most popular and most economical – as much as 30 percent less than electric (1).

2. Furnaces have been around for a long time

The Romans, circa 1200 BC, were the first known civilization to use any type of warm-air heating system. It was called a “hypocaust” and it pumped heated air through the walls and floors. During the 13th century, Cistercian monks used naturally flowing rivers, heated by furnaces, to warm their monasteries.

The very first steam-heating system was installed in England so that the Governor or the Bank of England could grow grapes during cooler temperatures (2, 3).

3. Furnaces help keep your pipes from freezing

During freezing temperatures outside, the water lines in a home without a heating system will freeze in approximately three days if they’re sealed (turned off and unused) (2).

4. Humidity affects how you feel, even at the same temperature

A very low humidity level will actually cause your home to feel colder than its measured temperature. A home kept at a rather high humidity level will actually cause your home to feel warmer than its measured temperature (3).

5. Furnaces are composed of three main parts

Although there are also parts such as filters, fittings, and ductwork, all furnaces contain these three components:

  1. A burner (in gas furnaces) or a heating element (in electric furnaces): This is how the heat is created;
  2.  A heat exchanger: The exchanger separates combustion gas from breathable air;
  3.  A blower: This part sends the breathable air through the duct system in the house (1, 4).

6. Furnaces have long lives

There are many factors that determine how long a furnace will last, but overall, they average lengthy lifespans. Conventional and mid-efficiency furnaces last about 18-25 years. High efficiency furnaces last about 15-20 years (1, 4).

7. The “Stack Effect” describes how air moves through a building

The Stack Effect principle refers to the movement of air through spaces, most specifically, the rising of heat in buildings. In the cold winter months, the warm air in the building is less dense than the cold air outside. That warm air bubble wants to rise up and out of the building.

This rising air causes cold air to be drawn into cracks at the bottom of the house. This is why your basement is colder than your highest floor. This is also why leaky houses consume larger amounts of energy (2, 5).

8. In Britain, “furnace” has a whole different meaning

In Britain, the term “furnace” only refers to industrial metallurgical furnaces used for smelting iron ore, lead or copper. In America, we call this type of industrial furnaces “blast furnaces”. The Brits call their heating systems “central heating” (3, 6, 7).

9. The word “furnace” has Greek origins

It’s said that the name comes from the Greek word “fornax” which means oven.

10. They really do require maintenance

Did you know the a 6 room house collects an average of 40 pounds of dust a year? You can see why regular maintenance of your HVAC is so important (8)!

Call the Experts at Greater Comfort Today For All Your Furnace Needs

We are proud to serve the Tri-state area of Northern Kentucky,
Southwest Ohio/Cincinnati, and Southeastern Indiana. Want to learn more about your home heating system—or just have more questions you’d like to ask to get to know us? Give us a call today at (859) 491-4915.


  1. http://www.breezewaysac.com/blog/5-fun-furnace-facts
  2. http://www.americanweathermakers.com/fun-facts.php
  3. http://www.huskyair.com/blog/infographic-10-fun-furnace-factoids/
  4. http://www.carsondunlop.com/home-inspector-training/furnace-fun-facts-getting-to-know-your-favourite-winter-appliance/
  5. http://www.greenbuildingadvisor.com/stack-effect-when-buildings-act-chimneys
  6. https://en.wikipedia.org/wiki/Blast_furnace
  7. http://news.bbc.co.uk/2/hi/uk_news/magazine/8283796.stm
  8. http://elite-hvac.com/page/1350-Did-You-Know




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