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Different Furnaces Explained

Different Furnaces Explained

September 24, 2018


It may not have been something you’ve actually thought much about in the past, but there are a wide variety of different furnaces out there that can be used to provide heat in your home. By far the most popular options are electric and gas and they have numerous advantages. They are both quiet and efficient, so they are not a disruption to your daily life, or when you are trying to sleep at night. In the following post, we will highlight the main types of both gas and electric furnaces.

How Do Gas Furnaces Work?

Gas furnaces take fossil fuel and transfer it into heat and are arguably the most economical and efficient form of heating. The average furnace does this by using blowers, heat exchangers and burners to transform the gas into heat the main kinds of gas furnace available are:

Single Stage Gas Furnace

In a single stage gas furnace heating system there is a gas valve. The valve opens and closes allowing gas to flow into it at a single, high rate, hence the name. A large number of this type of furnace operate at a yearly fuel utilization efficiency of up to 80%.

Two-Stage Gas Furnace

In a two-stage gas furnace, you have a valve that can be adjusted to allow the gas to flow at a high or low rate. This particular furnace system reads the heating load of your home via the thermostat and adjusts to provide the right amount of heat.

Modulating Gas Furnace

In a modulating gas furnace, the output of heat is adjusted far more precisely. The majority, regulate the output of heat by increases of 1%.

Oil and Electric Furnaces

Although they are not considered to be quite as economical, oil and electric furnaces are still a viable option. In an electric furnace system, the heat generated supplies warm air through the property. On the inside of the furnace, there are around three to seven electric-resistance coils. The air is passed through and over the coils and into the ductwork around your home. Oil furnaces are generally an option for households that have no access to renewable fuels like gas or electricity.

A Note about Furnace Efficiency Ratings

We mentioned earlier about the Annual Fuel Utilization Efficiency or AFUE. There are generally three categories that all furnaces are placed in:

  1. Furnaces with Obsolete Low-Efficiency: These furnaces are considered by most people to be out-of-date and produce an AFUE of 55% to 75%
  2. Furnaces with Low-Efficiency: All new furnaces must have a minimum AFUE of this amount – 78%
  3. Furnaces with Standard-Efficiency for Gas: 80%
  4. Furnaces with High-Efficiency for Gas: 90% to 98%



The choice of which furnace you should in your home if you are looking to upgrade or renovating and looking to buy a new system is up to you. Needless to say, you may have to look at local furnace duct cleaning companies to help keep your heating system well maintained. Dust may not sound like such a problem, but trust us, if dust is allowed to build-up it can play havoc with the efficiency of your system.