I did HVAC work in the late 90's till the late 00's. At that time, only the really expensive, high SEER rating units were variable speed. Cheaper 10-13 SEER s

I did HVAC work in the late 90's till the late 00's. At that time, only the really expensive, high SEER rating units were variable speed. Cheaper 10-13 SEER systems had scrolls but they were fixed speed.