Understanding the Different Types of Furnaces

If your home furnace is getting older, or you’re just interested in lowering your energy bills throughout the cold season, it’s important to learn about the different types of forced air furnaces. There are a few different types of furnaces and each offers specific benefits that you should be aware of.

Key Furnace Differences

There a few important differences between furnaces and how they operate. The first difference is how the furnaces generate their heat. Some do it in a single stage to create as much heat as possible, but others do it in two different stages and have more control over how much heat they generate. The second main difference in furnaces is how their blowers operate. The blower is what moves the heat generated throughout your home. Some furnaces run the blowers at full speed all the time. Others run their blowers at variable speeds, this major operational difference affects comfort and efficiency during use.

Single Phase Versus 2 Stage Furnaces: Which are Optimal

Older furnaces are all single phase products which means they generate heat at their maximum level all the time. This isn’t necessarily a bad thing because it makes the furnaces more affordable. If you care about efficiency and comfort though, a single phase furnace isn’t the best option. Two stage furnaces are known for being more efficient and often operate with an AFUE (annual fuel utilization efficiency) above 95% efficiency levels. Single phase units on the other hand usually operate with levels in the 80’s for AFUE.

There is a major efficiency difference between these two types of furnaces because of how they operate. Furnaces are at their most efficient after going through the warm-up phase and operating for longer periods of time. That’s why an oversized furnace is always less efficient than a properly sized unit is. A single phase furnace comes on, warms your home and shuts back off again. A dual phase furnace comes on at maximum power to warm your home during the coolest period of the day. After your home is warm it doesn’t shut off, instead it lowers to the low heat output level and continues to run and work to keep heat levels within a single degree or two of the thermostat’s settings. By continually running, a two phase furnace continues to operate efficiently and it simply cycles between the high and low heat output levels to keep your home at comfortable temperatures.

Standard Furnaces Versus Variable Speed Models

Some furnaces operate with blowers that run at the same power level all the time. These are standard furnaces. Others operate with a blower that speeds up and slows down depending on how much the temperature of your home needs to be increased. If the house only needs a small bump in warmth, the blower runs at a slower rate, using less electricity and creating a more comfortable environment. Not only that, but this style blower is shown to have a longer operating life as well and should keep your home at comfortable levels for years longer than your basic single-speed blower ever could. A variable speed blower can deliver the right amount of heat with precision and is often paired up with a two-stage furnace for peak efficiency.

Two stage furnaces are more efficient than single stage models, and furnaces with variable speed blowers take things a step further. These more modern and efficient furnaces are slightly more expensive, but they should make up for their added cost with efficiency improvements and a more comfortable environment all throughout their operating lifespan, which makes them a worthwhile investment to consider.