Question:
Dear Any Hour,
Is there a way that I can tell if my air conditioner is working properly?
– Robert H.
Answer:
This is a great question, especially right now when temps are the hottest, they’ve been all year and your AC is working the hardest. It’s important to know how to measure your unit’s effectiveness so you can be aware of any potential trouble during these months when you rely on your air conditioner the most.
To perform this simple test, the only tool you need is a probe-style thermometer.
Remember this is just a test to find out if your AC is cooling air effectively. To find simple tips on how you can perform maintenance on your AC, click here to watch this short video. Also, keep in mind that an HVAC technician would be able to dig deep and figure out why you’re experiencing problems; this is just a basic test to do a general diagnosis and find your unit’s baseline range.
For this test, you’re going to be measuring the return air temps and the supply air temps to see how much variation there is. Supply air is the air leaving your AC unit and dispersing into the home; return air is the air coming back into the system. By measuring these two temps, you can find out how warm the air is coming back into the system and what the difference is between the air going out and the air coming in. This different temperature difference to Delta T or the temperature split. Temperature split has to do with a range: if the temps are too high or too low on either end, there is likely an issue.
First of all, make sure that your thermostat has been running for at least 15 minutes. If you need to, bump the thermostat down lower so it continues to run throughout the test.
Next, you’ll need to go to the furnace to look for the return and supply air. If you have a filter on your furnace, finding these can be easy. The return air will be before the filter and the supply air will be after the filter, where your system turns to silver sheet metal. This is also called the plenum. Once you identify the plenum, you’ll need an access hole that’s large enough to insert the thermometer. If your system has already been serviced before, you may find that these holes already exist.
Next, insert the thermometer into the return. Wait for the thermometer to get a reading and then write down that temperature. Repeat this step on the supply side. You’ll then subtract the supply temp from the return temp. This number is your Delta T or your temperature split.
What you’re looking for is a temperature range between 18 and 22 degrees. If your temperature is either higher or lower than this range, you could be experiencing any number of issues with your system from restricted airflow to any number of mechanical issues. You may want an HVAC technician to come and diagnose your problem to get an accurate sense of what’s happening.
Hopefully, you found this video and suggestions helpful. Stay cool this summer!
Author: Amber Smith-Johnson
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