A good working a/c system should produce about 20* F of cooling or heating (heat pump).
1. Measure the temperature of the air blowing out of the register with a thermometer(stem, or laser). Eg. 60*F
2. Then measure the air going into the Return grill(with clean filter), with your thermometer. Eg. 80*F
3. Finally subtract the Return Air *F from the Supply Air *F to get your air
split. Return - Supply= 18-20*F
If your reading is Less than 18*F, you are Low on refrigerant. Which requires Professional help
to top off your system. Call 602-433-9241