They may look the same, but they don’t act the same! Here are the differences between a single stage AC unit and a 2 Stage:
Single-stage AC units operate at a fixed speed…they are either on or off. Two-stage units offer two speeds (low and high) and variable-speed units offer a range of speeds. Variable speed means that the unit operation “steps up” to the amount of cooling being called for. This has many benefits including more energy-efficient and less noise compared to single-stage systems.
Here’s more:
Single-Stage AC:
- Operation: Runs at full capacity when cooling is needed, then shuts off completely. While not terribly distracting, you can hear the unit click on and click off when the temperature set point on the thermostat is reached.
- Efficiency: Least energy-efficient due to frequent on/off cycles (short-cycling).
- Cost: Generally the least expensive upfront.
Two-Stage AC:
- Operation: Will run at a lower speed (generally at 70% capacity) for most of the time and only a higher speed when needed.
- Efficiency: More energy-efficient than single-stage, especially in moderate climates.
- Humidity Control: Better humidity control than single-stage due to longer run times at lower speeds.
- Cost: More expensive than single-stage, but potentially lower operating costs in the long run, meaning you’ll save money on utility bills!
Variable-Speed AC:
- Operation: Adjusts its speed continuously to match cooling needs, offering a wide range of cooling capacities. These units step up and step down to the amount of cooling being called for on the thermostat. Generally, they operate with less noise.
- Efficiency: Most energy-efficient of the three, minimizing energy consumption and those expensive utility bills.
- Humidity Control: Excellent humidity control due to its ability to run at low speeds for extended periods.
- Cost: Most expensive upfront, but can offer significant long-term savings.
For the most budget-friendly option with adequate cooling in mild climates: Single-stage is a viable choice. For a balance of efficiency and cost, especially in areas with humidity: Two-stage is a good option. And, finally, for maximum energy savings and superior comfort and humidity control: Variable-speed is the best choice, particularly in areas with significant temperature and humidity fluctuations.
Call Alaskan AC today if you are considering a replacement and we’ll provide a free quote for each of these options.