Single-Stage vs 2-Stage Air Conditioners
I've been looking for a low-tech way to describe the difference between single-stage and 2-stage air conditioners for awhile now, and I think I've found one that doesn't make customers want to roll their eyes and ask for the plain English version. So here's a super-simple way to think of the difference between single-stage and 2-stage air conditioning units...
Single-Stage Air Conditioning Units
Single-stage air conditioners are like a typical light bulb. They're either on or off, and when you turn them on they are 100% on.
So with a single-stage ac, it doesn't matter if the temperature outside is 80 degrees or 95 degrees, the unit will be working at full capacity. That's exactly what you want during the hottest days of summer, but not such a great thing when temperatures are more moderate.
2-Stage Air Conditioning Units
Two-stage air conditioners would operate more like a ceiling fan that has both a high-speed setting and a low-speed setting. (except we use the word stage instead of speed, but you get the point)
When the weather is warm enough that you need to run your air conditioning, but not hot enough that you need it blasting away at full strength, a 2-stage ac unit will run at the lower speed and still cool your home comfortably. Only when the temps are hot enough that the unit needs to operate at full capacity will the 2-stage ac unit ramp up to its high speed.