We at Air-Bon encourage you to call us at any time with questions about your HVAC system, no matter how minor or major the problem or question may be. However, before calling, you can consider checking to make sure your AC or heater is turned on. You could also check to see if the breakers and disconnects are turned on, and that the thermostat is set correctly. In addition, if you hear any strange sounds or smell any unusual smells from the system, take note of that as well.