When you are in the market for a new furnace for your Pittsburgh home, there are several reasons you should pay attention to the annual fuel utilization efficiency (AFUE) rating. All newer model furnaces get an AFUE percentage, which measures how much fuel a particular model converts into heat. Furnaces with higher AFUE ratings are more efficient, but the size and type of furnace will also factor into how much you’ll save on energy costs.
Understanding the AFUE Ratio
The minimum AFUE rating for new furnaces is 78%. This means that seventy-eight percent of the fuel is turned into heat, and the remaining percentage is lost either through poor insulation, air leaks, or the ventilation system in the home. Because there’s no heat loss through a chimney flue, some all-electric furnaces can have an AFUE rating as high as 98%. However, if the cost of electricity used to meet your normal heating needs is higher than the efficiency savings, you may want to consider other options. Talk to a qualified HVAC contractor for advice about the most cost-efficient heater for your home.
Furnace Efficiency Features
Furnaces manufactured 15-20 years ago have significantly lower AFUE ratings (between 55%-70% for most older models) because they are typically single-stage, or single-speed systems. Single-stage furnaces are less efficient because they are designed to cycle on at full capacity and shut off when the desired temperature is met. Newer, two-speed models have a second setting that runs consistently at a lower speed, which saves energy by burning less fuel. Multispeed furnaces that have variable-speed blowers are the most efficient because they operate at various levels and automatically adjust to the thermostat to maintain a constant temperature.
If you look at the AFUE ratings for multispeed and variable-speed furnaces, the ratios should be above 80%. Keep in mind that this only determines the efficiency levels for the furnace itself. You’ll need to factor in whether or not your home has proper insulation and other upgrades, such as double-paned windows and doors.