Why Won’t My AC Turn On?

There is no more important time to have AC than in the summer. Homes warm up as temperatures rise into the 80s and 90s during the day, especially poorly insulated homes without storm windows and window treatments. Finding out that your air conditioning isn’t working on a day that’s 100+ degrees could be devastating. Fortunately, there are some steps you can take to diagnose the problem and get your AC up and running again.

The Obvious Culprits

Sometimes the solution to your AC not turning on is simpler than you may think. Before you call a professional or look for a larger problem, check some of these small mistakes that could be the culprit.

It sounds painfully obvious, but make sure your thermostat is set correctly. It should be set to the “cool” setting and the temperature should be at least 5 degrees below the indoor temperature. If these settings are off in some way, the thermostat won’t tell the AC unit to turn itself on.

Sometimes your AC unit won’t turn on because of a blown fuse or tripped breaker. Check the main electrical panel in your home—older homes will have fuses and newer homes will have breakers. If a fuse is blown it needs to be replaced, but if the breaker is tripped all you have to do is flip the switch off and back on.

If one of these solutions fixes your problem but it occurs again in the future, you may have a more serious electric problem with your AC. If this is the case, you should call an AC repair company as soon as possible.

Other Causes

There will usually be a shut-off switch near your AC unit that allows you to quickly cut power to the AC in case of emergency or when performing maintenance. If you’ve recently had somebody out to work on your AC unit, they may have left the switch off. This is a simple fix—simply flip it back on.

There is also another switch which is located in your attic or crawl space. This switch controls the power for your blower and furnace. Its similarities to a light switch mean it’s often shut off accidentally, which makes your inside unit freeze and completely shuts down your AC system. If this switch is off, turn it back on and you should be good to go.

You could also have issues with your condensate drain line. Air conditioners work by compressing refrigerant before moving it through the condenser coil and using a fan to disperse cool air. The condensation created by this process goes through the condensate drain line, a small hose. When this line becomes clogged, it will immediately shut down your AC unit for safety purposes. You may be able to clear a clog in the line with a wet/dry vacuum. You may also have a condensate drain pump which could have triggered the same thing.

If your air conditioner has a reset button, give that a try. If it doesn’t have one, shut the AC off using the thermostat, wait for 5 minutes, and turn it back on. There is a more serious issue if this only provides a temporary fix.

If Nothing Works

So, what do you do if none of the aforementioned solutions work? Air conditioners are expensive units and require a lot of professional knowledge and experience to diagnose and repair. It’s also dangerous to work on electrical components without proper safety measures. Once you’ve ruled out all of these simpler solutions, your best bet is going to be calling an AC repair company to take a look at your unit.