Why Isn't Air Coming Out of Your AC Vents?

The thermostat is set to a cool 70 degrees, but it can be frustrating when the temperature in your house is searing and your home's vents or registers are glaring down at you with still indifference. If this has happened to you, then there are a number of possible causes. Luckily, most of them are relatively simple and cheap to fix. In some cases, you may even be able to take care of the problem yourself.

Check Your Breaker or Fusebox

If you're lucky, the problem is simply that the blower motor has tripped a breaker or blown a fuse. Before calling in a technician, check your breaker box and make sure that the circuit for your AC unit doesn't need to be reset. This may not be much of a concern if it only happens once, but if your blower motor seems to have acquired a taste for tripping breakers, then it's time to call in a professional for an evaluation. A breaker that is tripping on a routine basis indicates a wiring fault or a piece of failing equipment.

Check the Thermostats

Your home's thermostats function as an on/off switch for your HVAC system. When you turn the temperature on the thermostat down, it instructs your air conditioning unit to run until the thermostat's internal thermometer indicates that the room temperature has fallen to its target. If your thermostat isn't functioning properly, it will not instruct your AC system to come on.

Most thermostats are battery operated, so check and replace the batteries first. If this isn't the problem, reduce the temperature on the thermostat and have an assistant listen for the AC system to engage. If it doesn't, then your thermostat should be considered a possible culprit.

Check the Blower Belt

The blower for your HVAC system will be either belt-driven or direct drive. If the blower is direct drive, then you can ignore this section since there is no belt. If it's belt-driven, then a good next step is to check the condition of the belt. If the blower doesn't seem to be working at all, then you should expect to see if a belt that is completely snapped or sheared through. If the belt seems to be intact, then it likely isn't your problem.

Check the Blower Motor

Whether belt-driven or direct drive, your HVAC system's blower has a motor which can fail. It isn't always straightforward to check this part yourself, but you do have a few options. If your thermostat has a mode that engages only the fan, then turn it on . The blower motor should engage. If the breaker isn't tripped and the motor doesn't engage at all, then the motor itself may be bad. If you are unable to conduct this test or if it's inconclusive, then it's probably time to seek air conditioning repair services.