There are two different types of blower motors for your forced air system, the PSC (permanent split capacitor) and ECM (electronically commutated motor). PSC motors were the old standard, and if your furnace is over 5 years old it probably has one. Furnaces with an AFUE (Annual Fuel Utilization Efficiency) of 95 percent or higher probably have a furnace ECM motor.
If you don’t have an ECM in your furnace, you are literally blowing money out of your vents any time your central air or furnace is running. The big difference between the two models is that the PSC motor has one speed: full speed. Any time that the blower is on it blows at full force. The ECM model is a variable speed unit that will adjust the airflow to optimal levels based on the desired temperature of the home. This results in a 25 percent to 75 percent lower operating cost for the year. The ECM can use as little as 80 watts when running (that's less than a single 100 watt light bulb). To stick with the light bulb comparison, a standard PSC motor uses an average of 550 watts when in cooling mode and 510 in fan only mode: that’s five 100 watt bulbs. ECMs are also much quieter than PSC models.
One of the biggest improvements you'll see with an ECM is in overall air quality in your home. A PSC model will blow hard whether it is needed or not. This can result in the home getting to the optimal temperature too quickly to allow for the correct home humidity to be reached. The multiple speeds of the ECM allow it to reduce the drying effect that can happen during winter heating as well as eliminating cold and warm spots in the home.
The furnace ECM motor is fast becoming the industry standard. To learn more about it or how to get one installed in your existing furnace today, contact us here at Arpi’s Industries Ltd. We look forward to helping you create a more efficient and comfortable home.
Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems). For more information about furnace replacement and other HVAC topics, download our free Home Comfort Resource guide. Image courtesy of Shutterstock