Why is My Air Conditioner Not Cooling?


An AC that’s not cooling your home is a big problem.

After all, that’s its one job.

When your AC doesn’t perform as it should, it’s frustrating, time-consuming, and very hot.

There are several reasons your air conditioner may be failing to perform. We’re going to walk through each one – and how best to fix it.

1. Your Thermostat Isn’t Cooperating

Your first stop is your thermostat.

You should make sure that your thermostat is not only set to ‘ON’ but that it is set to ‘COOL’. Test that it’s working by setting the thermostat several degrees cooler than the stated temperature. You want to feel that chill!

If you can hear the air conditioner running, but minutes later still don’t feel any cool air coming through the vents, there could be something wrong with your thermostat and its electrical wiring. Fixing that problem is best left to a professional.

Dr. HVAC’s Note: You should also make sure all your windows and doors are sealed shut, and your supply and return vents are open and unblocked. It’s little things like this that are easy to forget about but super easy to fix.

2. A Breaker Has Been Tripped

Dr. HVAC’s Note: This tip is only for those homeowners whose air conditioners are not running at all.

Your AC runs on electricity. No electricity going to your air conditioner means no cool air making your home a summer paradise.

It’s time to travel to the location of your breaker panel, and do a check. The breakers for your air conditioner should be clearly labelled. Flip them off and on again, and see if this makes a difference.

3. Your Air Filter is Clogged

Next stop: the air filter.

Just because your air filter is located in your furnace’s blower doesn’t mean it isn’t used by your air conditioner. Your furnace’s air handler is what pushes the cooled air through the filter, through your ductwork, and into your home.

Therefore, if your air filter becomes clogged with dirt and debris, it’ll act a lot like a cork in a bottle: little to nothing is getting past it.

We recommend checking your filter once a month, and changing it at least every 3 months – more often if you have hairy pets, allergies, or a lot of people living in your home.

Air filters can be found at local hardware and home stores.. Make sure you replace your current filter with one that is the same size.

4.Your Outdoor Unit is Coated in Dirt and Debris

Sensing a theme here? Dirt is no friend to an air conditioner.

Your air conditioner condenser is located outside your home, and left exposed to the elements when in use. After awhile, all that wind and rain is bound to blow some dirt and debris into it.

If there’s too much dirt, your condenser can’t perform the heat exchange process efficiently.

There are things you can do to help with this particular problem. For example, tidying up the landscaping around your condenser will help keep branches, bushes, and other vegetation from adding to the debris buildup. We recommend keeping about 46 centimetres of space clear on all sides of your condenser.

You should also wash your condenser regularly with water and soap. Gently wipe away dirt from the condenser fins, being very careful that they don’t break.

In the off season, make sure your condenser has a cover and it is secured tightly. To defend yourself against dirt and debris, you may want to consider an air filtration system to keep your air quality clean.

5. Houston, We Have a Mechanical Problem

While annual maintenance is an excellent want to reduce your risk of mechanical breakdowns, they can still happen.

Whether it’s a broken fan motor or compressor, a mechanical problem could be the reason your AC is not cooling properly.

If you suspect a mechanical problem, you should call us right away.

6. The Refrigerant in Your Air Conditioner is Leaking

Air conditioners use continuously circulating refrigerant to cool air. Normally the level of refrigerant never changes and your air conditioner is perfectly fine.

If you spring a leak, that refrigerant level drops – and so does the amount of cool air you get.

Refrigerant leaks can be identified by ice buildup, hissing noises, or a noticeable decrease in cooling efficiency.

If you think you have a refrigerant leak, turn off your air conditioner and call us right away. This is a problem that should only be handled by experienced professionals.

7. Your AC Wasn’t Properly Installed

Unfortunately we see this all the time with both air conditioners and furnaces.

An improperly installed air conditioner just won’t provide the cool air you need in an efficient manner.

This is something you’ll notice after you get a new air conditioner. We can provide you with a second opinion, and do what we can to fix any potential problems.

Dr. HVAC’s Note: The size of your air conditioner is also incredibly important. If it’s too big or too small, you won’t be able to efficiently cool your home. Before you buy an air conditioner, meet with a qualified home specialist who can perform an evaluation and make recommendations.

8. Your Ductwork is Leaking

Any cracks or spaces in your ductwork will let cool air seep out and away. It’ll never reach you, and you’ll think your AC is not cooling your home.

In fact, it is – just not where and the way you want. That’s a waste of your money, and is incredibly frustrating.

We can perform a ductwork inspection, diagnose the problem, and provide recommendations for next steps.

9. Your Air Conditioner is Over the Hill

There comes a day when even the best air conditioner in the world just gets to be too old.

Generally after 15 years, you want to start paying close attention to how your air conditioner performs. If it gets to a point where you’re spend hundreds of dollars a year to keep it going, or your AC is not cooling your home at all, it’s time for a replacement.

The experts at Dr. HVAC can perform an in-home consultation and walk you through the latest models, making recommendations for your home and your needs.

Get Help from the Professionals at Dr. HVAC

When your AC is not cooling your home, the best thing to do is call in the experts. We’ll respond quickly, arrive on time, and get your cool air back as soon as possible.

After we get the cool air back, we can keep it that way with annual maintenance. A tune up each year will not only minimize the risk of breakdowns, but will increase the lifespan of your AC and save you money on your energy bills.

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