How To Tell if Your AC is Running Efficiently


During a hot summer like this one, your AC is probably running non-stop. As a homeowner, you want to make sure that your AC unit is efficient. An inefficient system will have you spending an unnecessary amount of money on your utility bills. The extra money you are spending on your monthly utility bills can add up to a new efficient system, fast! If you want to find out whether your system is efficient or inefficient, then keep reading. 

There are a few telltale signs that can indicate that your current AC unit is inefficient. One of the signs, in our opinion, the most important sign – is insufficient cooling of your home. For a homeowner, this could be the most frustrating sign because the AC is not doing its primary job in your home and not keeping you cool! Also, if your unit is inefficiently cooling your home – it takes a longer time to reach the desired temperature. This means your system is running longer than it should and is adding to your utility bill!

Now you might be wondering, can I check the efficiency of my AC unit at home? The answer is YES!

Here is how you can test the efficiency of your unit at home!

Step 1: Turn your AC on

Testing the efficiency of your system is the most effective on hot days, preferably when it is 80 degrees or higher. Turn your AC unit on and leave it running for at least 15 minutes. 

Step 2: Put a thermometer in a supply register

The supply register supplies cool air throughout your home. Put the thermometer in the supply register that is closest to your AC unit. Placing it by the closest supply register to your unit, to register the air closest to the unit – before it has traveled throughout the duct system is most effective. Keep the thermometer on the supply register for at least five minutes to get an accurate reading. 

Step 3: Put thermometer on a return vent

If you are not sure what a return vent is, typically it is the larger vent and it is the vent sucking in air. If you place a piece of paper by a return vent it should be pulled toward the vent. Again, leave the thermometer in the vent for about 5 minutes. 

Step 4: Determine if your AC unit is efficient or not
If your AC is functioning like it is supposed to, the air coming out of your supply vents should be 15 degrees colder than the air that is sucked into your return vent. If not, do not fret just yet!

Step 5: Improve AC efficiency at home

There are a few things that you could do on your own to improve the efficiency of your unit, try…

  • Changing the air filter

  • Making sure your doors and windows are closed

If your AC’s efficiency still did not improve, it might be time to call the experts!

Step 6 (The Final Step!): Call Duct Professor at 847-994-3994!

There are a few services that could be recommended by our HVAC technician.

  1. Keeping up with your annual maintenance – by performing seasonal AC and furnace maintenance you can keep your system running smoother & longer, it can also help your unit function properly during peak season. 

  2. Get a duct inspection – having a technician take a look inside of your duct system with a wired camera can help determine if you have any blockage in your ducts preventing the airflow. This can help determine if there is any damage in your duct system that is preventing airflow, or whether you are in need of a duct cleaning. 

  3. If your system is old, our technician might suggest a replacement unit with a higher SEER rating, which is a sophisticated term for an efficiency rating. SEER is calculated by cooling output during summer divided by energy used during summer, the higher the SEER the more efficient the unit is.