Customer had concerns of long run times of ac unit on 90 degree hot days. Home is a split level brick house with a sun room attached on the back. Only issue I found was a dirty filter in the system. Unit has an 8 degree sub cooling and a 20 degree delta T. Put in a clean air filter, closed a couple vents in the lower level, and explained that the system will run for a long time when it is close to 90 outside and they have thermostat set to 70 degrees. The new equipment is built with efficiency in mind.