Is It Too Cold Outside to Run My AC?

Here is my understanding of some but not all of the HVAC residential companies doing business today. They hire service tech's that are not well trained but can do miminal service and be a parts changer. I was a residential service tech from the 1970's and worked on systems using R-12, R-22 and R-500. I read everything I could get my hands on so I could always find the answer to almost any problem. If you know the "refrigeration cycle" you can make a system run in almost any temperature extreme. We had systems back then that could run in ambient temps down to 30 degrees F. and sometimes lower with the right control system. Good service techs are hard to find so if you find one call him only and do not be afraid to compensate him well.