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Multi-Speed Vs. Single-Speed Furnaces

Are you shopping for a new furnace for your Woodbridge, Virginia, home? If so, it’s important to understand the difference between multi-speed and single-speed options. Your budget, energy efficiency goals and home comfort preferences will determine which system is ultimately best for your needs. Learn more about how multi-speed and single-speed furnaces work.

How Single-Speed Furnaces Work

A single-speed furnace has only one type of heat output. The furnace is either on or off. It’ll turn on any time the temperature drops below the thermostat setting and run until it achieves that temperature. The furnace then turns off again until the temperature falls.


  • Cheaper upfront cost.
  • More common installation that service technicians are familiar with.


  • More expensive to operate.
  • Less nuanced temperature control.
  • Shorter lifespan.

How Multi-Speed Furnaces Work

A multi-speed furnace can operate at several speeds. You’ll find two-stage or three-stage systems that have intermediate stages that may alternate between using 50% and 100% of the system’s power, or 40%, 65% and 100%. You can also select a variable-speed furnace. This option uses incremental adjustments to manage your temperature using the exact amount of energy necessary.



  • More expensive upfront cost.

Choosing the Right System

If you’re looking for a new furnace that will keep your initial costs low, a traditional single-speed furnace is typically the cheapest option. However, if you can afford a two-speed system, this is a better option. A variable-speed furnace is an ideal choice if you can fit this installation into your budget. Though this furnace is more expensive up front, it will have a longer lifespan and lower operations costs. As a result, it can serve your budget better over the long-term.

If you’re shopping for a new furnace for your home, Brennan’s Heating & Air Conditioning can help. Give us a call at 703-783-0145 to learn more about your options. We’ll help you find the right heating system for your needs.

Image provided by Shutterstock

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