No furnace is meant to last forever, regardless of how durably it’s built. Once a gas furnace is older than 15 years, it’s time to start thinking about a replacement. And if a furnace is older than 20 years, it’s time to stop thinking about a replacement and just replace it.
There are many reasons to replace an older furnace, but one of the most important is that a newer furnace will have superior energy efficiency; i.e. it will convert more of its fuel source into thermal energy and waste less. This isn’t simply because a newer furnace will have reduced levels of wear and tear. Newer furnaces are simply more efficient to start with, constructed with better technology. Where many older furnaces had efficiency ratings (AFUE) of 60%–80%, meaning they converted 60%–80% of their energy source into heat, new furnaces can score much higher… sometimes as much as 97%.
How Energy-efficient Gas Furnaces Work
There are a number of different technologies that permit new furnaces to score higher ratings. One of them is the change to electronic ignition systems. The old standing pilot light that used to ignite the burners consumed energy throughout the season, even when the furnace didn’t need to run. An electronic ignition system only uses a small amount of electricity when the furnace comes on, reducing the waste of natural gas used for a pilot light.
Special high-efficiency units have a number of other improvements. A condensing furnace contains a second heat exchanger, which takes the exhaust vapor from the first exchanger and runs it through condensation in order to extract more heat from it. Older furnaces simply vent away this vapor, but a condensing furnace draws more thermal energy out of it.
Multi-Stage and Variable Speed Furnaces
Multi-stage furnaces and variable-speed furnaces permit a heating system to run at different power levels. Instead of simply being “on” or “off,” these furnaces can modulate their burners and the blower fan motors to operate at energy-saving lower capacities. The furnace automatically adapts to the home’s conditions to use the lower level when it’s sufficient for comfort.
If you’re looking to install a new, high-efficiency furnace this season, call Comfort Flow Heating in Eugene, OR. Quality service and install since 1961!