With spring on the way and warmer temperatures, now is a good time to double check your home’s AC. One test that you as a home owner can do is to check the temperature at the return register and the supply vent. You should have a 15 degree or greater difference between the two. Anything less than 15 degrees means your system is having to run longer to do the same work. Increasing energy cost. A lot of times this issue can be solved with a licensed mechanical contractor adding freon to the system. Having the system inspected annually by a licensed mechanical contractor is a good idea as well.