The Variable-Speed Furnace and the Variety of Benefits It OffersIf you’re considering a new furnace for your home, you’ll want to look at an energy-efficient variable-speed furnace. New features, such as the variable-speed blower motors that operate in these furnaces, have changed the way furnaces operate, creating energy savings and increased comfort.

Compared to a traditional furnace, a variable-speed furnace provides more even and steady heating. A traditional furnace operates at one speed, switching on the heat that runs until it reaches a specific temperature. A variable-speed furnace, on the other hand, adjusts the blower speed to meet your heating needs. It can slow down or speed up rather than running at one speed.

A variable-speed blower motor, working with ECM (electronically commutated motor) technology, delivers heat at variable speeds to control the amount of heat flow with more precision. It works with sensors that control the airflow between the flue and burner. On days when full-go heating isn’t required (which is most of our mild heating season in Central Arizona), the furnace runs longer, but at the lower setting. During extremely cold weather, it runs on at full capacity to provide maximum heat. These variable-speeds let the blower motor run longer without the frequent on-and-off cycling of a traditional furnace. For homeowners in mild-winter climates, like Phoenix and Scottsdale, variable-speed furnaces will operate on the lower setting 90 percent of the time.


  • Increased comfort – temperatures stay at a more comfortable level when the blower runs longer.
  • Even temperatures – temperatures are adjusted to meet heating needs in your home. The blower doesn’t cycle on and off frequently, so heat gets distributed more evenly .
  • Cleaner air – as the blower motor runs, it pushes air through the furnace filter. Running longer allows more air to go through the filter, resulting in cleaner air.
  • Less noise – all blower motors create some noise, but variable-speed models run much quieter than single-speed models.
  • Energy-efficiency – variable-speeds save energy because they don’t cycle on and off, and the start-up phase in a furnace is the time when the most energy is consumed.
  • Heat-efficiency – variable-speeds adjust heat flow as needed, providing more efficient air flow.

For more expert advice on a variable-speed furnace and your home comfort, please contact us at  Wolff Mechanical. We provide complete air conditioning and heating services for Phoenix, Scottsdale and Central Arizona.

Our goal is to help educate our customers in the Phoenix Valley area of Arizona about energy and home comfort issues (specific to HVAC systems). 

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