Got an Air Conditioner that Won't Work? How to Fix Common Problems

Before calling an air conditioner service technician, there are some simple fixes worth trying first. If your air conditioner won't cool, stops running or is too noisy, you might just luck out and be able to solve the problem yourself.

If you've ever felt totally stupid after paying a small fortune for someone to come out and replace an air conditioner filter, this article is for you. Starting from the top.....

What if my air conditioner doesn't seem to run or cool the house properly? Does this mean I have to buy a new unit?

Not necessarily. First of all, check the circuit breakers. Although this might seem like an obvious first choice, it can be forgotten when you are hot, grumpy and feel on the verge of heat stroke. If you can reset the circuit breaker, you are good to go.

If that doesn't work, check to see if you have a blown fuse, usually found in older homes. If so, make sure all power to the appliance controlled by the fuse is turned off, take out the fuse and replace it with one that is the exact same kind and with the same amps. This is vital because the wrong fuse can cause serious issues, well beyond a blown fuse.

If the circuit breaker or fuses aren't the problem, listen for any noise coming from the air conditioner. If it seems to be running but not cooling the air properly, make sure you've changed the filter recently. Yes, this is one of those "duh" moments, but a clogged air filter can greatly reduce or even stop the air conditioner from cooling a home.

To clean the filter, turn off the air conditioner. For window air conditioners, the filter is generally located behind the front cover and can gently be removed (never pull or rip it out, no matter how desperate).

For whole house air conditioners, you may need to use the user's manual to locate the filter. If you've lost the manual, call the company and ask them to tell you where the filter can be found in your particular unit. Make sure you know whether the filter is washable or has to be replaced with a new one each time the old filter gets dirty.

Once the filter is replaced, you could feel comfortably cool again. It is amazing how much a dirty air filter can affect the performance of an air conditioner. While you are at it, make sure there are no leaves, plants, dirt or debris which are interfering with your air conditioner's ability to run. Make a note to yourself to change the air conditioner filter monthly and to keep dirt from building up and affecting performance.

What if my air conditioner keeps turning off even if the house or room isn't cool?

Ask yourself when you last vacuumed the coil fins. If you don't know what they are, look for exterior coils, generally wavy, located on either the outside of your air conditioner or right inside the front cover (most large units have coils located behind a panel grille).

As with all actions taken to check your air conditioner, turn off the power to the unit before proceeding any further. Now you can gently vacuum the coils. If they are very dirty, you'll want to borrow or rent a shop vac to get the best results.

Next, make a trip to the hardware or home supply store and ask for a fin comb. These will help straighten the coil fins and help your air conditioner work better. If those coils need deeper cleaning, get a commercial power air conditioner solution from an air conditioning repair service or HVAC supplier. You'll need to moisten the coils before spraying the air conditioner with the solution, letting it set and washing it off. Don't use a power sprayer to do this. A garden hose should be strong enough.

What if my air conditioner is too noisy and I can hear rattling sounds, even when inside my house?

Try a simple visual inspection and see if loose screws are adding to the noise factor. If they are, tighten them (again, with power to the air conditioner turned off). If that doesn't solve the problem, you may need professional help to lubricate the fan. However, ask the repair person to show you how to do this yourself because it many air conditioners can be lubricated by the average homeowner, once the proper steps are learned. Since air conditioners can vary, it is best to have someone provide instructions on how to oil the fan before you attempt this yourself.

If you've tried all these steps and still have problem, your thermostat or other air conditioner parts may not be working properly and you'll need to call a service professional.