ECM Vs. Condensing Furnace

ECM

• If you are looking for a furnace that features the latest in technology, then you need to look at one that has an ECM. They use about the same amount of energy as an 80-watt light bulb. ECMs use anywhere from 25 to 75 percent less energy than standard furnace motors, according to Minnesota Power. What makes them so energy-efficient is that they are brushless, which enables the motor to adjust its speed and produce optimal airflow at all times. An ECM motor can be used in any type of furnace -- gas, propane, oil or electric.

Condensing

• A condensing furnace uses just about everything that comes its way and converts it to heat. For example, instead of exhausting residual moisture and gases, a condensing furnace recycles this matter into usable energy to heat your home. First, it converts every drop of fuel or kilowatt of electric power into heat. Whatever is not used is vented outdoors through a pipe where it is collected and turns into condensation. The condensation is then recycled back through the furnace system where it is reconverted back into heat.

Similarities

• Condensing furnaces and ECM motors represent the best options for maximizing the efficiency of a furnace. If you were to select both -- a condensing furnace with an ECM motor, you would have a furnace with state-of-the-art capabilities. Furnaces are given AFUE ratings (Annual Fuel Utilization Efficiency). This tells you the amount of energy that the furnace actually converts to heat. A condensing furnace with an ECM motor could easily have an AFUE of 90 to 95, meaning the energy loss can be as low as 5 percent, and 95 percent of the energy will actually convert to heating. A furnace that's 20 years old might have an AFUE of only 60 or 70 percent.

Differences

• A condensing furnace is a system, and an ECM is a component of a furnace system, just as the fan and pilot lights are parts that make the furnace function. A condensing furnace does not require an ECM to operate, and the same holds true for an ECM -- it can be used with a condensing or a noncondensing furnace. A condensing furnace can work with a standard motor.