Understanding 1-stage vs. 2-stage heating systems

Schwank 1-stage vs. 2-stage

Debunking the technology


With more technology available, there is a shift to moving away from equipment that generates higher operating costs.

This shift has been especially prevalent in the HVAC industry by introducing equipment with stages and, ultimately, variable/modulating technology.

But higher operating costs aren’t the only item being combated. Depending on the application, other important factors should also be recognized: the life of the equipment and comfort.

Traditionally, we only had on/off systems. These 1-stage systems are either 100% one or entirely off.

Even with introducing new technology, we continue to focus on ‘what is traditional’ and maintain adopting the 1-stage system design.
Over time, this new tech has become ‘robust,’ and there really should be a need to explore other systems.

With 2-stage systems (especially within a heating system), you have an intermediate setting before approaching 100%.



In the HVAC industry, a 2-stage heater allows the equipment to operate at a lower capacity to bridge the minor gap to reach setpoint. This 2-stage, in turn, reduces the amount of fuel that would normally be used in a 1-stage to reach setpoint.

It also helps reduce short-cycling effects that can harm the equipment/component life. Imagine getting to a 100% only to turn off completely, then turn on again (via purge cycle) and back to 100% – this is exactly what occurs in a 1-stage system. This strain is additive and degrades components, eventually leading to failure.

Having a 2-stage heater system with a lower capacity also gives users some flexibility on their setpoints and comfort.

With changing environmental conditions, having 100% can simply be uncomfortable. But in 2-stage heating systems, you have that intermediate setting that uses less fuel and energy and can maintain a user’s comfort (for that changing environment).

For small to medium-sized buildings, the 2-stage system provides an economical option to users by not only looking to reduce operating costs but also prolonging the lifespan of their equipment. It creates a more comfortable working/relaxing environment.

Learn more about the Schwank 2-stage infrared tube heaters >

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