Annual Car Air Conditioning Performance Test

When you turn on your car air conditioning for the first time this season, will you be happy with the results? Did the air temperature seem colder last year? Here will answer these common questions and provide an action plan to identify problems.

Human Perception of Cold Air

When drivers turn the air conditioner on for the first time in five months they can’t help, but compare this year’s results with those they remember from the previous year. It’s a popular complaint that the air just doesn’t seem as cold as the year before. Since it’s not uncommon for the air-conditioning to lose Freon when not in use during the winter months it’s a likely hypothesis.

Unfortunately, this suspicion is based purely on conjecture. Here we’ll talk about running an annual air-conditioning performance test and recording the results so next year you can repeat the process and compare them. This way you won’t have to question your sanity when it appears your air-conditioning is slowly losing its performance.

Car Air-conditioning Performance

An air-conditioning performance test is a process of achieving and recording the lowest possible temperature reading from the dash vents. Although you could just stick a thermometer in the center air duct and grab a reading, this will not represent the lowest number possible. Plus, you’re looking for a standardized procedure performed in exactly the same way year to year.

If you’re interested I have a recent article focusing on getting the most out of your air conditioner. Here we’ll use some of these techniques in an attempt to gain a reliable reading. The coldest air exits the center vents with all of the other air ducts in the closed position and recirculation or maximum air selected. The blower should be set for the lowest speed setting. The slower the air travels the more heat is removed from it. A temperature probe is then inserted into the center vent and allowed to stabilize before recording the reading.

Automotive AC Performance Test Tips

A small standard kitchen thermometer makes an inexpensive and reliable tool for taking automotive air-conditioning output readings. The temperature range of these instruments is usually -10 degrees on the cold side to 200 degrees Fahrenheit on the hot side. Since our desired results are in the 40 to 50 degree Fahrenheit range it will fall in the middle of the scale. Invest in a separate temperature probe and keep it in the glove box. You’ll find it very convenient if you have repeat air conditioning problems.

Once you get the readings, purchase a miniature notebook from the dollar store and record the findings. Keep it simple just write down the date and the temperature. Keep this small notebook in the glove box along with the temperature probe and a pencil. This makes the test fast and convenient anytime the air doesn’t feel cold enough. Also, get into the habit of performing an air-conditioning performance test at least once a year. The first time you turn on the AC in the spring season is a great time to do this.

Analyzing the Results of the AC Test

Chances are you weren’t imagining things and the car’s air conditioner is slowly losing its ability to cool. Although it will ultimately take some diagnosis to get to the root cause of the issue. We can apply some general rules of thumb to the situation. The modern air-conditioning system holds about a pound and a half of Freon. It’s not unheard of for a vehicle in perfect condition to lose 1-2 ounces over a year’s period of time as small amounts of Freon escape from the rubber O-rings that seal the different components. In this situation recharging could be required every five years or so.

Another issue to address is the health of the air-conditioning compressor. This is one of the hardest working components in the entire automobile. As the vehicle ages, the compressor through normal wear and tear can become less efficient at pressurizing the high side of the air-conditioning system. Although no one can tell you just how long an automotive AC compressor will last. If the vehicle has over a hundred thousand miles and the air is not as cold as it uses to be this part becomes a likely suspect.