Is your air conditioner really doing its job, or just running up your energy bill? Testing your air conditioning unit’s efficiency can help you find out whether it’s cooling your home properly, or wasting power in the process. Proper testing can determine whether you need a new ac unit install or just need to schedule professional hvac maintenance. In this blog, we’ll walk you through how to tell if your air conditioner is not running well and a few simple ways to check your system’s performance so you can stay cool and save money all summer long.

How Do I Know If My AC Unit is Not Running Efficiently?

Higher Energy Bills:

A sudden or gradual increase in your monthly energy costs can point to an overworked, inefficient system.

Uneven Cooling:

If some rooms feel cooler than others, your AC may be struggling to distribute air properly.

Longer Run Times:

If your unit runs longer than usual to reach the set temperature, it’s likely losing efficiency.

Warm Air or Weak Airflow:

Air coming from the vents should be strong and cool, if not, something could be wrong with the system.

Frequent Cycling:

An AC that constantly turns on and off may be short-cycling, which wastes energy and strains the unit.

Unusual Noises or Smells:

Grinding, rattling, or musty odors can indicate internal issues that reduce performance.

Step 1: Get Warmed Up-To Cool Down

Make sure your unit has been running for at least 15 minutes. Letting your AC unit run for about 15 minutes before testing its efficiency gives it time to reach a stable operating state. When it first turns on, the system is working to cool down and balance internal pressure, so readings taken too early can be misleading. Allowing that brief warm-up ensures more accurate temperature and airflow measurements, giving you a better picture of how efficiently it’s performing.

Step 2: Take Your Temperature

Next, take the air temperature at the return vent, this is where the system pulls in warm air to cool it down over the evaporator coils. These vents are usually located on the ceiling and often near the thermostat. Hold your thermometer right in front of the vent, or place it just inside, and let it sit for at least 5 minutes to get an accurate reading.