The majority of households throughout the Rocky Mountain region rely on
a central furnace to provide heat. A central furnace works by blowing
heated air through ducts that deliver the warmed air to rooms via registers
or grills. Central air furnaces are often called a ducted warm air or
forced warm air distribution system. They can be powered by electricity,
natural gas, or fuel oil.
If you have a natural gas or fuel oil furnace, the fuel is mixed with air
and burned. This produces flames, which heat a metal heat exchanger where
the heat is transferred to air. The air is then pushed through the heat
exchanger by the air handler furnace fan, then forced through the ductwork.
Throughout this process, combustion products are vented outside through
a flue pipe. While older furnaces often vented directly into the atmosphere,
wasting about 30 percent of the fuel energy, current minimum-efficiency
furnaces reduce this waste by using an inducer fan to pull the exhaust
gasses back through the heat exchanger and induce draft in the chimney.
A condensing furnace is designed to reclaim much of this escaping heat
by cooling exhaust gasses to the point where water vapor condenses into water.
In the US, furnace efficiency is regulated by Annual Fuel Utilization Efficiency,
or AFUE. AFUE estimates seasonal efficiency, which takes into account
start up, cool down and other operating losses that occur throughout operation.
Think of AFUE like your car’s mileage expectations. To calculate,
you have to include all operating conditions, including highway driving
and stop and go traffic. AFUE accounts for all fluctuations that occur
during normal living arrangements. The higher the AFUE, the more efficient
your heating system will be.
While central furnaces are considered the norm, many Colorado homes operate
using a boiler system. Boilers are special purpose water heaters that
distribute heat in hot water as it passes through radiators or other devices
in the various rooms of a house. As water cools, it returns to the boiler
to be heated once again.
Instead of a fan and duct system, a boiler uses a pump to circulate hot
water through pipes to radiators. Some hot water systems circulate water
through plastic tubing in the floor, called radiant heating. With this
system, it is easy to install zone thermostats and controls to allow you
to set each room individually.
Which system is right for you?