What Are Variable Speed Motors, and How Do They Impact My HVAC System?

Sometimes, you need to spend more to save more. Most HVAC units operate on a low-cost single-speed motor that cycles on and off according to your thermostat setting. While these work well enough for most homeowners, an upgrade to a variable speed motor can change the way you use your HVAC unit.

Although some homeowners can be scared off by the price, variable speed motors can end up saving them more in energy bills in the long run. If efficiency is a priority for you, it may be worth your time to consult with an HVAC specialist about an upgrade.

What Is a Variable Speed Motor?

Variable speed motors adjust their speed and torque to match your HVAC unit’s output instead of running at a fixed rate, increasing and decreasing its speed according to your thermostat’s settings. A variable speed motor running at half speed moves the same amount of air as a single-speed motor while only utilizing 25 percent of the same energy. You can end up saving thousands in utility spending over the life of the unit – surpassing the amount it cost to upgrade your motor.

They give homeowners more precise control over the system’s output and, consequently, the energy consumption of their HVAC system. They can also provide faster performance if you feel like your home cools down too slowly. This responsiveness not only reduces your system’s workload, extending its lifespan and delaying replacement.

Many modern HVAC systems, especially the higher-end models, come with variable speed motors. The feasibility of replacing a single-speed motor with a variable speed motor in an existing system will depend on compatibility and your current control system. If you want to learn more, you should consult with an HVAC specialist.

How Do Variable Speed Motors Compare to Other Motor Types?

• Single-Speed: Single-speed motors operate at a fixed speed and are unable to flexibly respond to immediate heating and cooling needs.

• Double-Speed: Double-speed motors offer two fixed settings – high and low – making it slightly more flexible than a single-speed motor but less adjustable than a variable speed motor.

• PCS: Permanent Split Capacitor (PSC) motors are a type of single-speed motor that utilizes a balanced two-phase motor to produce uniform torque and speed. Although they can be built with multiple speed settings, they lack the performance of true variable speed motors. These are generally being phased out due to their lack of energy efficiency and issues with heat build-up and loud volume.

• Constant Torque: Constant torque motors provide a more consistent torque output. Although it can have multiple speed settings for a more customized experience, it still lacks the adaptability of variable speed motors.

Benefits and Drawbacks of Variable Speed Motors

Variable speed motors can maximize your HVAC unit’s efficiency while minimizing your energy consumption, enhancing comfort and decreasing costs. Because variable speed motors operate on a gradual startup and shutdown schedule, as opposed to an abrupt start and stop, they can also help preserve your HVAC unit’s lifespan, reducing wear and tear and limiting the need for repairs and replacements.

The biggest downside of variable speed motors is the cost. These systems can be more expensive, but their increasing use and options on the market make them accessible to all types of homeowners.

The return on investment is not immediate. Like many efficiency upgrades in your home, it can take years for the energy cost savings equal the added expense.

The complex designs of variable speed motors can also make maintenance more complicated and the cost of repairs higher if breakdowns occur. Single-speed motors are easier to maintain due to their simplicity.

Despite the slightly higher upfront cost and increased complexity, the performance and efficiency benefits of having a system with a variable speed motor installed typically outweigh the potential disadvantages.

Our Experienced Technicians Have Repaired, Replaced, Installed and Modified HVAC Motors in Arlington for Over 60 Years

If you want to find out if it’s possible to upgrade your current HVAC unit’s motor or learn about the potential advantages of replacing your current HVAC system with one that incorporates a variable speed motor, we can help. At Tom’s Mechanical, we’ve worked with every type of HVAC system. We’ll use our experience and expertise to thoroughly inspect your existing unit and help you figure out which air conditioner or furnace will serve your needs best.