Single vs. Variable Speed Exhaust— Who Reigns Supreme?

Enervex MBES

When completing building projects or retrofitting the HVAC for existing facilities, strategically selecting a dryer, kitchen or bathroom exhaust system is key. With the option of single, multi, and variable speed exhaust, you may be considering which will best suit your project. Although the initial investment is greater, variable speed systems provide the best performance benefits and cost-savings down the road.

The benefits for variable speed exhaust over single speed exhaust include:

Increased Efficiency: Most single speed exhaust systems typically run at full power when they are on, regardless of what amount of energy is needed. Variable speed exhaust systems contain a speed controller that sense the amount of power needed to reach a certain pressure at any given time. This means less energy is wasted and output is more efficient. Additionally, because single speed exhaust fans are constantly running at full speed, they can exhaust a ton of conditioned air to the outdoors, resulting in increased air conditioning/heating costs for the building.

Noise Reduction: The greater the power output of a fan, the more noise it makes. This means that single speed exhaust systems running at full power are significantly louder than variable speed exhaust that only put out the precise amount of power required at any given time.

Longevity of System: Although it may seem counterintuitive, exhaust that constantly turns on and off experiences much more wear than systems that remain running. More fatigue is placed on system components when they continuously stop and start. Running at full speed also increases the amount of heat created, degrading the grease of the bearing system and thus shortening the life span of the machine. Variable speed exhaust does not get as hot as single speed and requires little to no reboot. For this reason, variable tends to last much longer than single speed and require less maintenance over its lifetime.

Shop UEP’s selection of variable speed exhaust models here.