Our central air conditioner unit is over 15 years old and recently it hasn’t been working quite as reliably as we’d like. Even though I’ve been doing my best to care for my central air conditioner is appears that mine might on its way out. About once every couple of days now it simply “stops” coming on and I have to try a bunch of different things to get it working again. I was planning on getting a new central air conditioner in the next year or two anyway, but it looks like I may be doing it a little earlier than I had anticipated.

Without getting too technical I thought I’d share with you a couple steps you can try before calling in the air conditional repair (or sales) guys:

1. Make sure you’re setting the AC thermostat properly: Some thermostats don’t immediately turn on the unit and some have a 2 or 3 degree temperature “window” they use to gauge whether the air conditioner should switch on or not.

2. Make sure your AC thermostat is working well: A lot of homes have electronic thermostats these days and most run on battery power. Those batteries do have to be changed from time to time. My electronic thermostat supposedly had a low battery indicator, but I’ve found that changing the batteries before seeing the indicator has helped in the past. An electronic thermostat is just an automatic switch that basically turns your AC unit on and off at certain temperatures. If the batteries are low the switch may not be turning on or reading the air temperature properly.

3. Check your air conditioner’s fuses and circuit breakers: A central air conditioner may have several different fuses in the whole electrical system. First try resetting the fuse for your central air conditioner at your electrical box by turning it off and then on. For my system I have to then go to my furnace/blower and flick a second switch on and off. This switch turns off whenever I turn off the main electric to it. A third fuse is probably outside on the wall next to the air conditioner unit or on the unit itself. Unless you know what you’re doing I wouldn’t recommend trying to change out these fuses which are often not on switches from what I’ve seen.

4. Check any AC reset buttons: Some newer air conditioner units have reset buttons which are essentially just fuses as well.

5. Wait 15 Minutes: This sounds silly, but after a recent power outtage from a thunderstorm we found that our central AC wasn’t kicking on. Our electronic thermostat was blinking “Cool On” which meant that the thermostat was, in theory, working, but the AC wasn’t responding. I went through the house resetting circuit breakers, hitting the reset button and doing just about everything I could think of. Finally, I just turned everything off (shut off the fuse, turned off the AC on the thermostat) and just… waited. I purposely waited about 15 minutes because I remembered that some AC units purposely won’t power on for a certain amount of time after a circuit has been tripped. Me flicking the circuit breakers back and forth probably didn’t help. After the 15 minutes was up, I flipped the circuit breaker back on, went to the thermostat, crossed my fingers, and turned on the AC. It started running almost immediately!

6. Read your central air conditioner’s operations manual: I put this last because, let’s face it, you’ve probably lost or never had the operations manual! If you can find the operations manual to your central air conditioner unit you may want to investigate to see if there are any recommended troubleshooting suggestions. By the way, if you know the brand and model of your central air conditioner you may actually be able to find a copy of the manual online. The same is true if you’re not sure of how your electronic thermostat works.

If you’ve tried most of these and still can’t get your AC working then the problem could be less of an electrical one and more of a mechanical one. Remember: be safe! If you’re uncomfortable trying any of these steps then call a qualified air conditioner repair person!

From what I’ve seen most central air conditioners have a lifespan of about 12 - 18 years, though I once lived in a house with a little unit that was 22 years old and still running well. Though it might cost you $2,500 - $5,000 to replace it’s important to remember that a new one will be much more energy efficient than your old unit and you’ll have a little more peace of mind when you see those triple digits pop up on the weekly weather forecast!

Good luck and stay cool!