Single Speed vs Variable Speed Motor

When you are in the market for a new furnace motor you may be wondering what the advantages and disadvantages would be in choosing a single speed vs variable speed motor. A single speed furnace uses a PSC motor whereas a variable speed uses an ECM. To determine which one best fits your needs it is important to understand the main differences between them.

Single Speed Furnace

Single speed furnaces have only one stage of heat output – high. A single speed furnace uses a PSC motor or a permanent split capacitor. This type of motor is designed to turn on and off; it is not programmable and there are no speed variances that can be controlled. Although they are low cost to install, they are not the most efficient type of motor or the quietest. It constantly operates by dispersing the maximum amount of heat it is designed for when on. This can result in costly energy bills because every time the furnace is turned on it is dispersing the most amount of heat at a constant speed using constant energy.

Variable Speed Furnace

With a variable speed furnace, rather than working in an on or off mode, the blower automatically adjusts to different speeds to control the amount of heat dispersed throughout the home. This type of furnace uses what is called an ECM or electronically commutated motor. Having an ECM results in better electrical efficiency, heating consistency, air quality, noise reduction and lower energy bills. An ECM motor will gradually come on and gradually increase to meet the settings set by the thermostat resulting in a quieter unit. The advanced technology of an ECM can correspond to the units need for air flow and can account for things such as dirty ductwork or filter and furnace location. Furthermore, even when not on it can operate to circulate the air throughout the home constantly passing the air through the air filter resulting in better air quality. Compared to a single speed furnace, a variable speed furnace is more effective at drawing moisture from the air further improving indoor air quality and comfort. Simply put, better air circulation provides better balance of temperature and humidity control and a higher level of comfort. This in turn can eliminate the need for the furnace to operate often since the air is being distributed throughout the home and can result in lower energy bills.

LA Construction Heating and Air is a certified HVAC Contractor. We would be happy to assist you with any questions you may have in deciding which furnace would be best for your home or business. Feel free to contact us online or give us a call today at (818) 341-3406. To learn more about services our company offers, please visit our homepage.