System operation?
Having trouble choosing the system that fit you?
Modulating is going to be the most efficient and will give you the most consistent comfort. These systems are designed to run for most of the day but at a lower capacity to limit the temperature swings. The most typical operating range is 30-100%, meaning it will only utilize what it needs to maintain your set temperature. Giving you a constant flow of conditioned air never letting your home get uncomfortable. The best part is all of the typical parts that fail over time; capacitors, contactors, and relays are not used on this system! Which in turn makes this system much more reliable.
Dual-Stage systems are going to be more efficient than single-stage and have a high and low stage with set capacities. These systems will share many of the same parts that are found in single-stage systems; capacitors, contactors, and relays. The system will operate in the low stage (Typically 70% capacity) for a set period of time, and if it does not reach your set temperature in that period it will then go into the high stage (100%) until the desired temperature has been met. The Temperature swings will be reduced from those of the single-stage and run times will be lengthened.
Single-Stage systems are likely just an updated version of what you currently have with all the same componentry. The temperature will vary during operation in order to achieve your desired comfort temperature. The system will turn on at 100% until it meets your desired temp, then turn off until it rises to 1-2 degrees above your set temp. It will repeat this throughout the day.