- Is the thermostat set correctly?
- Are the batteries in the thermostat good (for battery operated thermostats only)?
- Is the filter compartment blocked?
- Is the filter dirty?
- Is the outdoor unit dirty, plugged, or blocked?
- Has the breaker tripped?
Things to keep in mind:
- The a/c will cool your home at most 21º cooler than the outside temperature which means on a 100° day your home may cool to 79°
- The heater has a safety feature that will delay it from starting up too quickly after it has recently turned off (delay times vary; most common is 2-5 minutes)
- Added heat load such as a hot attic, poor insulation, or windows that are sun facing, single pane, or lightly covered may contribute to more frequent use of your air conditioner