What is Furnace? | What are the types of Furnaces?

The furnaces are used all over the world. The furnace is most commonly used to heat the building because of its high compatibility, long service life, low operating noise, and efficiency. They have very high flexibility. The furnace is, also known as the forced air system, is the heart of the home’s central air system, which produces hot air and cold air. This article mainly explains the working, types, and other aspects of the furnace.

What is a Furnace?

A furnace is a mechanical device that generates and distributes hot air throughout the desired area. The furnace is a basic part of the HVAC system.

This is an oldest heating system that is still most commonly used in commercial and residential buildings. Conventional furnaces were used wood or coal to generate heat, while the latest furnaces use electricity, propane, and natural gas.

As the furnace generates hot air, it transfers into your home through a duct system. The furnace is most commonly installed in the crawlspace, attic, closet, or basement.

Before buying a furnace, you must keep in mind some important factors such as the efficiency of the furnace, price, type of brand, and your residential area where you want to install it.

Types of Furnaces

The furnace has the following major types:

1) Single-stage Furnace

The single-stage furnace is also known as a single-speed furnace. This type of furnace works at a single speed. The valve which supplies gas to the combustion chamber has two settings, fully open and fully closed. This furnace constantly distributes hot air in the room at its maximum power.

2) Two-stage Furnaces

These types of furnaces have the capability to operate at two different speeds. Therefore, the two-stage furnace is also known as a two-speed furnace. It is more efficient than the single-stage furnace. It uses a three-position valve. You can set this valve in the fully open, partially open, or fully closed position. This is more efficient than the valve of the single-stage furnace.

 The first stage (partially opened condition) of the two-stage furnace operates at 65 percent capacity and operates comfortably even in cold weather. As the temperature goes down and the first stage heat is insufficient, the furnace will switch to the second stage (on or fully heated) for extra heat production.

The two-stage furnaces are the most commonly used type of furnace in the home because they are more energy-efficient than single-stage furnaces.

3) Variable Speed Furnace

The name of the variable speed furnace refers to the speed of the blower fan/motor. In simple words, this furnace’s blower motor/fan works at a different speed. However, it doesn’t operate at different speeds to achieve the desired temperature. It has an adjustable fan which allows you to expel the necessary heat to the environment and thus save on energy costs.

Types of Furnaces According to the Fuel

1) Gas Furnace

The natural gas furnace is the most commonly used furnace type in homes. The gas is used to run the furnace. It utilizes gas supplied by municipal pipelines. A jet of gas in the combustion chamber is ignited to produce hot combustion gases.

The temperature of the resulted hot gases increases the temperature of the air. As the temperature of the air increases, it circulates in the ducts by means of a fan.

These furnaces are inexpensive to run due to their high efficiency and lower gas prices compared to other fuels.

2) Oil Furnace

If natural gas is not available, you should use oil to fire the furnace. In an oil furnace, the oil is combusted into the combustion chamber and generates heat. This generated delivers to the air, which then circulates in the ducts via a fan. The maximum oil furnace (primarily used in the frigid environment of the Northeastern United States) transforms oil to heat.

However, the oil furnace has less efficiency than the gas furnaces. Oil also has more costs than gas.

3) Electric Furnace

If you don’t have a natural gas line in your home, you can switch to an electric furnace. These types of furnaces utilize an electrical heating device to transfer heat to the air. One of the main advantages of these furnaces is that they have low buying cost and small size than other furnaces. You can easily install them in a small area.  

However, they have low efficiency than gas furnaces, but they are the best option in some situations.

You can also use an electrically powered heat pump to cool or heat the building. Maximum people prefer heat pumps to use heat instead of a furnace to improve efficiency and comfort. The heating or cooling via heat pump is also referred to as hybrid heating. However, in the mild winter, you may only use a heat pump with installing a furnace.

4) Modulating Furnace

The modulating furnace has high costs, but it has many advantages over other furnaces. It regulates the amount of gas burned to achieve the desired temperature of the thermostat.

It permits you a more accurate temperature determination, typically within ½°F margin of error which other furnaces may turn off at 4-6°F.) Instead of wasting energy by constantly turning on and off, the setting of this furnace will run at lower power levels all the time. This furnace will still provide you with your desired heat but with low power consumption.

They lower the energy cost because they consume low energy than other furnaces.

5) Propane Furnace

This furnace uses propane as a working fuel. Propane is a by-product of gas and oil. You can easily store it in a storage tank. Almost 10% of American homes use this furnace. The propane furnace is the best suitable option if gas or oil isn’t available in your area.

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