If you’re thinking of
replacing your furnace and you live in Portland, then saving energy is likely at the top of your
priority list. AFUE ratings are a way to assess the energy efficiency
of furnaces and boilers. AFUE is an acronym for “annual fuel utilization
efficiency." It is calculated as a ratio that compares the heat output
of the device to its fuel consumption. For example, if a furnace has an
AFUE rating of 95%, this means that 95% of the fuel consumed heats the
home, while the remainder is lost.
If you’re in the market for a new furnace that saves energy, you’ll
want to choose a heating system that has an AFUE rating between 90% and
98.5%. These heating systems feature sealed combustion and a second heat
exchanger that condenses flue gases. You might also consider talking to
your HVAC technician about retrofitting your current furnace to save energy
if you’re not quite ready for a replacement yet. In addition to
making your furnace energy efficient, other options include installing
a programmable thermostat and upgrading your ductwork.