Heating technology doesn’t stand still. It is constantly advancing, and that’s why modern gas furnaces are more energy efficient than the furnaces of 30, 20, or even 10 years in the past. But simply saying that “technology got better” isn’t really saying that much. What exactly makes the new furnace so efficient?
And New Furnaces Are Indeed Much More Efficient
Before we get into why furnaces are more efficient, let’s look at exactly how much more efficient they are today than in the past.
The measure of furnace efficiency is AFUE (annual fuel utilization efficiency), which is the percentage of natural gas the furnace converts into heating power. Older furnaces have an AFUE range of 56% to 70%, which means that between 30% and 44% of the natural gas goes to waste as heat bleeds from the combustion chamber and exhaust leaves the flue. New furnaces, however, can have AFUEs from 80% all the way to 98.5%. In order for a gas furnace to earn the ENERGY STAR certification, it must have an AFUE of 90% or greater.
The Secret of High Furnace AFUE
A number of technological improvements have allowed furnaces such improved efficiency. Not all furnaces have these developments, and you can always ask HVAC professionals to assist you with finding the right high-efficiency unit for your needs.
- Lighter heat exchangers: The heat exchanger is the part of the furnace that transfers the heat from the combustion gas to the air from the air handler. Lighter heat exchanger construction makes them more effective at warming the air than the older, heavier ones.
- Electronic ignition systems: The standing pilot light that has been used for decades to ignite furnace burners is now out of date. Electronic ignition systems are now in use, and these require far less energy. A standing pilot light drains power as it waits for the burners to come on, while an electronic ignition only uses power when it is needed.
- Sealed combustion chambers: Older furnaces have atmospheric combustion chambers, which means they’re open to the rest of the house, and therefore lose some heat to the outside. The current sealed combustion system draws the air it needs through a PVC pipe to the outdoors and doesn’t lose extra heat. (This system is also safer and prevents the furnace from drying out the house.)
- Two-stage furnaces: The older burners in furnaces are either on or off; whenever they’re on, they work at maximum capacity. A new multi-stage furnace can run at lower capacity when necessary, saving energy and also helping to distribute heat more evenly around a home.
- Variable speed fans: Similar to the two-stage burners, variable speed fans in furnaces can change from maximum capacity to work at a lower speed and use less energy.
When you are ready for a great new furnace installation in Evanston, IL, you have more options to consider than ever before. Our technicians are here to see that you have the right type of furnace, one that has excellent energy efficiency, but also matches your home’s heating needs and your budget.
Malek Heating & Cooling—Serving the Chicagoland area since 1998!