What You Need to Know About Furnaces

How does a furnace work?

Home furnaces can run on both propane and natural gas. The flames from the furnace heat up a metal heat exchanger and the heated air is blown into the ductwork around your home.

What are the different types of furnaces?

There are 3 different types of furnaces you’d likely want to consider:

  1. A forced air furnace. These furnaces pull the cold air of your home into their vents, pass it through an air filter, blow it by the heat exchanger to warm it up, and then blow it back into your home through the furnace’s various ducts and vents.
  2. A wall furnace. This type is what’s known as a “radiating furnace”. These furnaces don’t have vents and use either convection or radiant heating instead. They work for smaller spaces but are easier to install.
  3. A floor furnace. These are also radiating furnaces and work similarly to the other type above. The difference is in the name – while wall furnaces are typically installed on walls, floor furnaces are fixed to the floor. This is a popular type of furnace in old people’s homes.

What are the main components of a furnace?

Home furnaces have 3 main systems:

  • The heat source, i.e. the furnace itself where the fuel is burnt and the heating element heats the air.
  • The heat distribution ducts that deliver the heated air around your home.
  • The control system, i.e. the thermostat or a different control device which allows the user to interface with the furnace and operate it.

Floor and wall radiant furnaces have much simper heat distribution mechanics as they don’t aim to heat up an entire house but simply radiate heat around them. Other than that, they are pretty similar in terms of how they work.

Here are the main components that make up the systems of a standard home furnace:

  • The burners – these are the tubes where the gas is directed to and burned.
  • Heat exchanger – the metal tubes where the air sits while it’s being warmed up by the burners.
  • Blower fan – this is the fan that will redirect the heated air back into your home.
  • Draft or hood fan – this is the fan that will suck cold air into the furnace to be heated up.
  • The flue – this is the vent that will guide the combustion gases into the chimney and out of your home.
  • Thermostat – the most common control device which monitors your home’s air temperature and operates the furnace according to your preferred temperature settings.

How to light a furnace?

Different types of furnaces are ignited in different ways so reading the instructions manual of your furnace thoroughly is a must before you do anything with it. Furnaces that are equipped with an electronic igniter, for example, can’t be ignited manually – instead, turning the igniter off and resetting it will likely be the way to go.

What is the typical furnace run time?

This will also depend on the type of furnace but most forced air furnaces will typically cycle 2 or 3 times per hour. This can also depend on the temperature outside, on your desired temperature, on your home’s insulation, on how well the thermostat is working, and so on. In particularly cold days a furnace can cycle as quickly as once every 10 minutes.

Furnace maintenance

There are several key things you’ll need to do regularly to keep your home furnace operating as effectively and as efficiently as possible:

  • Replace the air filters once every 3 months of furnace operation. If you wait any longer than that the filters will get more and more clogged and will not only fail to properly filter the air in your home but will also slow down the operation of your furnace.
  • Clear the assembly of your furnace’s blower regularly – about once per season.
  • Get your burner cleaned once per season as well. This is best done by a professional.
  • Perform routine annual check-ups on all the systems of your furnace. You can call a professional to not only clean the furnace’s burner but to perform an overall maintenance check-up.

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