Variable speed air conditioners can run from 30% to 100% capacity, which is controlled by a variable speed compressor or, in the case of an air handler or gas furnace, a blower motor. The technology allows the system to run at different levels depending on how much cooling you need. It reduces energy usage during the start/stop cycle and helps maintain the desired temperature, so it doesn’t need to compensate for temperature swings. Variable speed cooling also helps improve the temperature/humidity balance and allows more time to filter circulating air.