Gas furnaces have made significant improvements over the years. The efficiency of new gas furnaces ranges from anywhere to 80% all the way up to 98% (most efficient).
Of course, the more efficient the unit is, the more it will cost up front to buy it, however, the energy and gas savings you receive will essentially pay for the unit itself over time.
What Does A Furnace’s Efficiency Rating Mean?
As stated above, furnaces come in efficiency ratings of 80% to 98%. You will commonly see this stated as AFUE (Annual Fuel Utilization Efficiency). But what does this mean exactly?
It’s basically a measurement of how efficient the gas is burned off at the furnace when it is running. With an 80% efficient gas furnace, 80% of the gas supplied to it is used in directly heating your home.
Things To Consider
- Number of windows in your home
- Number of people living in your home
- Temperature preferences
- Layout and existing duct work in your home (if applicable)
- Type and quality of insulation in your attic and walls
- Preferences in efficiency and price
Gas Furnace Options
When it comes to a new gas furnace, you have a couple different options to choose from other than the overall efficiency of the unit. The type of motor the furnace has as well as the choice between a single state versus a multi-stage are other options to be considered.
Most older furnaces are all single stage furnaces. This means that when you turn your unit on, it comes on full blast and remains that way until it reaches the temperature you have set on your thermostat.
Once the temperature in the house reaches the temperature you have your thermostat set at, your furnace turns completely off until it is needed again. Unfortunately, this isn’t the most efficient way to heat your home.
When you buy a multi-stage furnace, your furnace will come on at high speed at first, and then once it reaches the desired temp, it will kick down to a lower speed and remain there to help sustain that temperature.
Furnace motors are meant to run for long periods of time. It is actually more stressful on the motor to have to keep turning on and off than to just run continuously at a lower speed.
Electronically commutated motors (ECM) have been around for a while now. They have several benefits compared to the standard motors that come in lower end units.
- Efficiency – EC motors have an infinite speed range, as opposed to just an “on and off” mode. By running continuously at various speeds, the efficiency at which your furnace heats your home is greatly increased.
- Fan always on – By having the motor run constantly in a lower speed, you are able to make use of your furnace filter and keep the air in your home cleaner.
- Dehumidification – When you run your air conditioner in the summer, it also works as a big dehumidifier. By having an EC fan, you have the option to increase this humidity removal process.