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Air Conditioning Checking

How to Test Your Central Air’s Cooling Ability

Updated: Feb 10, 2023

Picture this: your air conditioning system seems to be running fine, but it’s just not producing the cooling power you need during the harsh Florida summer. Why? This is an all-too-common problem with air conditioning systems and an inquiry we frequently receive phone calls about from homeowners. So why does this happen? While there are numerous reasons this issue can occur, you can easily check your AC’s cooling ability before placing a phone call to your technician, which can rule out certain factors.

Learn how you can test your central air conditioning system’s cooling ability in five simple steps:

Central Air’s Cooling

What You’ll Need

– Screwdriver – Thermometer – Small Pry Bar

Testing Your Air Conditioner’s Cooling Ability

Step 1. Turn on your air conditioning system and set the thermostat well below the temperature of your home, which will keep your system running so you can perform the test.

Step 2. Locate an air duct that is close to your air conditioner’s indoor unit and return air duct. Remove the grilles from both.

Step 3. Take a thermometer (a refrigerator thermometer will work fine) and tape it to the inside of the air duct. Let your air conditioning system run for 10 to 15 minutes before reading the temperature on the thermometer.

Step 4. While your air conditioning system is still running, move the thermostat to the return air duct. Leave the thermostat here until the temperature reading is steady.

Step 5. Subtract the return air duct temperature from the temperature in the incoming air duct.

The Results Are In…

If you air conditioning system is functioning efficiently, the temperature difference (between the air duct and return air duct) should fall between 14 and 20 degrees. If the temperature difference is less than 14 degrees, here are three potential reasons why this is occurring:

Low Refrigerant Levels: As the refrigerant levels dip below the normal range, your air conditioning system will continue to run, but the air it produces won’t be as cool as it should be. A professional HVAC technician will be able to recharge the coolant and check for refrigerant leaks.

Dusty Evaporator Coils: Over time, dust builds up on the evaporator coils, insulating them and making it harder for your AC to produce cool air. You can clean the evaporator coils yourself or schedule an appointment with a technician if you’d rather leave the job to a pro.

Dirty Air Filter: In order for your AC to function efficiently, the air filter needs to be changed regularly. When you neglect to change the air filter, dirt, dust and the like builds up, making it harder for your AC to cool your home. As a result, you may notice that your system is still blowing air, but it never seems to get cold enough. Be sure to change the air filters in your home at least once per month.

The 18 Degree Differential

It’s important to keep in mind that a fully functioning air conditioner cannot exceed an 18 degree differential from the temperature outside. So when the temperatures are in the 90s, the lowest temperature your AC will be able to reach (considering it is functioning efficiently and has no air duct leaks) will be in the 70s. Older air conditioning systems have a harder time reaching the full 19 degree differential. While this can be frustrating, there are small efforts you can make to keep your home cool during Florida’s hot summer, such as keeping the blinds and curtains closed during the day, running ceiling fans and avoiding using the oven.

AC Repair In Orlando

While you can easily test your central air conditioner’s cooling ability, some jobs are better left to the professionals. At Energy Air, we offer quality AC products and services that keep your home cool for less. If your AC is blowing air that isn’t cool enough, schedule a maintenance check or a repair with our team and we will restore your home’s comfort.

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Contact Energy Air

Whether you need a single air conditioning unit installed or a complete air conditioning system retrofit, our team of HVAC experts will handle it. Have questions or would like to discuss your project? Give us a call today to talk to one of our friendly team members, or schedule your appointment online.

Orlando: (407) 501-6275 | Tampa: (813) 314-7261

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