The Difference Between a Single Stage and Two Stage Air Compressor

The main difference between single and two stage compressors is the number of times that air gets compressed between the inlet filter and the storage tank. In a single stage compressor, the air is compressed one time; in a two stage compressor, the air is compressed twice.
The process that takes place within a single stage compressor goes as follows:
1. Air is sucked into a cylinder
2. The trapped air is compressed in a single stroke with a piston at roughly 130 psi
3. The compressed air is moved onward to a storage tank
In the storage tank, the compressed air serves as energy for the assortment of tools that a single stage compressor is built to accommodate.
The process within a two stage compressor - alternately referred to as a dual stage compressor - is similar to that of a single stage, but with one variation: the compressed air isn’t sent to a storage tank; it’s instead sent to a smaller piston for a second stroke, this time at roughly 175 psi. From there, the double-pressurized air is cooled and delivered to a storage tank, where it serves as energy for vast arsenals of high-powered equipment.
People who are new to air compressors will often confuse the number of cylinders for the number of stages in an air compressor, when in fact both single and two stage compressors use two cylinders, because it’s easier to balance air that way. The difference between the two stage air compressor vs. single stage in this regard is that, in the latter, both cylinders are the same size. On the other hand, in two stage compressors, the second piston is shorter than the first, and the two are linked by a cooling tube, which brings the temperature of the air down before the second round of compression.