One of the biggest advancements in modern HVAC technology is the development of variable-speed HVAC motors. These types of motors have several major advantages over standard HVAC motors, and they can provide many excellent benefits to your home. In this article, we’ll explain how variable-speed HVAC motors work, how they compare to standard motors, and what benefits you can enjoy by upgrading your air conditioner or heater to a variable-speed HVAC system.
Standard vs. Variable-Speed HVAC Motors
A traditional central AC or heat pump has a single-stage compressor motor that always starts at full power and runs at full speed. The blower or fan in any standard AC, heat pump, or furnace system also has a single-stage motor that only operates at top speed. As the name suggests, a variable-speed motor has multiple speed or power settings that it can switch between as needed. That means the AC or heat pump compressor can speed up or slow down to adjust the rate at which the refrigerant flows through the system. The system’s variable-speed blower can also do the same to control the rate and volume of air currently circulating throughout the building. The purpose of the motors speeding up or slowing down is to more effectively control the system’s cooling or heating output based on the current temperature inside the building while at the same time minimizing the system’s energy usage.
How Do Variable-Speed HVAC Systems Work?
A standard single-speed HVAC system normally cycles on and off two to three times per hour as long as it’s working effectively. Variable-speed systems, on the other hand, are meant to run the majority of the time at a fairly low speed. On hotter summer days, a variable-speed system often runs continuously for the entire day until it finally starts cooling off outside in the evening. In colder climates, a variable-speed heating system may sometimes run for days on end without shutting off.
When the system first cycles on, its motors start running quite slowly, so they experience very little strain when powering up. The motors then begin ramping up their speed as necessary to increase or decrease the temperature in the building.
Once the building is within a degree or two of the thermostat setting, the motors start slowing down again, so the system continually maintains a consistent temperature. That way, the building doesn’t get too hot or cold, preventing the system from having to shut off. It’s better for the system to cycle on and off as little as possible, as this reduces wear and tear and strain on the motors.
How Variable-Speed Motors Reduce Energy Usage
One of the main benefits of a variable-speed HVAC system is that it costs far less to run than a standard single-stage system. However, single-stage systems have issues. Their motors require a lot of energy to constantly run at full power, and they typically cycle a few times an hour.
Even though variable-speed systems run for many more hours a day, they still use much less energy since they operate at a lower speed about 80% of the time. The motors also draw far less power when turning on since they start at a lower setting and only gradually speed up when necessary. When a single-stage motor turns on, it’s like slamming on a vehicle’s gas and trying to go from 0 to 60 as fast as possible. Doing that uses much more gas than just gradually getting the vehicle up to 60, and this same concept applies to variable-speed motors.
Many systems can slow down to around 25% of their full speed, in which case they use close to 75% less energy than they would while operating at their maximum capacity. Most of the time, the system will run at no more than 50% capacity, ensuring you pay far less for cooling and heating. On average, a variable-speed HVAC system will save you at least one-third of what you would pay in energy costs with a standard system.
How Variable-Speed Systems Improve Temperature and Humidity Control
Another great thing about variable-speed HVAC systems is that they are far better at controlling both temperature and indoor humidity. With a standard system, you end up with the temperature in the house continually fluctuating by at least a few degrees as a result of the system frequently cycling on and off. There can also be times when the system may not stay on long enough to fully cool or heat every part of the house.
With a variable-speed system, your house will usually stay within a degree or so of the thermostat setting. If you turn the temperature down when you’re away for the day and back up when you get home, the system will run closer to full speed until your house nears the desired temperature. It will then slow back down so that the temperature stays almost exactly where it should be. You’ll also have far fewer problems with hot and cold spots in your house since the system will just keep running and pumping out a smaller amount of warm or cool air into every room.
Variable-speed cooling systems also work far better at preventing the house from being too humid. All cooling systems remove moisture from the air as they run due to moisture condensing on the system’s evaporator coil. Nonetheless, variable-speed systems remove much more moisture since they stay on for longer periods instead of just cycling on for short bursts, as single-stage systems do.
How Variable-Speed Systems Reduce Noise
Another benefit of variable-speed systems is that they are generally far quieter than single-stage systems. When the system is running on a lower setting, you’ll often barely be able to hear the blower or the outdoor unit. However, the system can still make just as much noise when it’s at the highest setting. Nonetheless, this doesn’t happen often, and it typically never takes that long before the system slows down and produces significantly less noise.
Atticman Heating and Air Conditioning, Insulation is a locally owned and operated company that has been serving Sacramento and the surrounding areas for years. We’re dedicated to providing reliable, customized cooling and heating solutions and work with each customer to find the best option for their home. We also offer expert attic insulation, ductwork, water heater services, and indoor air quality services. If you’re considering a variable-speed system for your home, we can explain all of your options and help you choose the one that suits your specific needs. You can also rely on our expert technicians whenever your HVAC system needs any repairs or maintenance services. We are dedicated to exceeding your expectations with our highly trained technicians, high-quality work, and exceptional customer service. Customer satisfaction is our top priority on every project.
Contact us today to set up a consultation with one of our installation professionals and find out if variable-speed motors are a good choice for your home.