When considering air conditioner options, the question of whether to choose a unit with a single stage or two stage compressor inevitably arises. The answer depends on a wide range of factors. In order to figure out which one works best for you, it can be helpful to have an idea of how each one works and what might make you want to choose one over the other.
The Mechanics of Single Stage and Two Stage Compressors
Fundamentally, the difference between single stage and two stage air compressors is the process by which the air is compressed within the air conditioning unit in order to generate the power needed for operation. In a single stage air compressor, the air is drawn into the cylinder and compressed to about 120 psi in a single piston stroke. From there, it is transferred to a storage chamber. In contrast, there is an extra step in this process for two stage compressors. After the initial compression in the first cylinder, the air is moved to a second, slightly smaller cylinder where there is another piston stroke, this one at about 175 psi. Only then is the air transferred to the storage tank, where it is ready to be used to power the air conditioning unit.
What Does That Mean for the Air Conditioning Unit?
Operationally, this means that a single stage air conditioner only works at one level. Any time the temperature in your building exceeds the temperature at which you set your thermostat, the air conditioner automatically runs until the set temperature has been reached. Then, it turns off until the temperature rises again.
But with a two stage air compressor, the air conditioner can work at two speeds. When temperatures start to rise, the air conditioner runs on low speed, maintaining a mild environment. Only when conditions really start to heat up does the high level of operation kick in.
Evaluating the Benefits and Drawbacks of Air Conditioners with Single Stage and Two Stage Air Compressors
When making the final decision between an air conditioner with a single stage compressor and one with a two stage compressor, there are a few key factors to consider, including:
- Efficiency. Because they can run at two different levels, air conditioners with two stage compressors operate more efficiently than single stage compressors, especially when temperatures are warm, but not blazing.
- Upfront cost. Although choosing an air conditioner with a two stage compressor may be able to save you money in the long run by working more efficiently, upfront costs for air conditioning units with single stage compressors are typically lower.
- Maintenance and repair. Two stage air compressors have a longer lifespan than single stage compressors, so they need to be replaced less frequently. At the same time, it is easier to conduct routine maintenance on single stage compressors, and they are less expensive to replace.
Ultimately, the decision to choose an air conditioner with a single stage compressor or a two stage compressor depends on the needs of your building, as well as your personal preferences and budgetary constraints. Both are great options for different users.