If you have spent any time around HVAC, either in a classroom or just chatting up an HVAC technician, there is a decent chance you’ve heard the expression “beer can cold.” “Beer can cold” is an expression that originated in the early days of air conditioning, back in the ‘50s and ‘60s. It was created to describe the temperature at which an air conditioning system has been properly charged with refrigerant.
The idea is if you were to grab a properly charged suction line it would be as cold as a cold beer can. It is also a completely irrelevant, incorrect, and outdated expression that shouldn’t be applied anywhere near modern-day HVAC. In fact, if you ever hear a fellow HVAC technician using that term earnestly turn the other direction and run away.
“Beer can cold” is an expression that no longer holds any relevance for HVAC technicians and should be left in the past. If you are an HVAC technician or in training to become one, here are three reasons to forget everything you may know about “beer can cold.”
What is “beer can cold” anyway?
One of the biggest arguments against “beer can cold” is that in a very precise industry this kind of measurement is not even remotely precise. What is the exact temperature of “beer can cold?” You can technically drink beer at any range of cold temperatures and different folks may have a different take on what the ideal temperature of a cold beer is.
Also, a beer out of a cooler full of ice maybe 32 degrees and one out of the fridge maybe 35 to 38 degrees, but they feel relatively the same to the touch. Air conditioners today are manufactured with distinct specifications on charging temperatures, and the tools HVAC technicians have at our disposal today make taking accurate temperatures much simpler than relying on getting a relative temperature by hand.
“Beer can cold” is misleading
Extremely hot working conditions are very common for HVAC technicians, especially here in Houston. If you were to grab a suction line that is about 50 degrees on a 100-degree day outside, that suction line is going to feel extraordinarily cold even though it is only 50 degrees. Now, if you grab that same suction line when it is only 60 degrees outside, it is not going to feel anywhere near as cold. Also, if there is a lot of moisture in the air, the suction line will be wet and feel colder than a dry line at the same temperature.
Aside from not having an exact reading for “beer can cold,” taking a temperature by hand can lead to horribly inaccurate and misleading readings that can lead to serious errors during installation and repair. Using this method on the job will likely cause you to make serious mistakes.
It’s not the ‘50s anymore
The truth about “Beer can cold” is that even though it is an expression that began in the ‘50s, it was an outdated expression even back then. So much about air conditioning in the past 60 years. Back then, compressors were oversized, coils had a lot of extra space, and fan motors were higher in horsepower. Flexibility in the charging of refrigerants was not a significant issue since a pound over or under would not cause any drastic changes.
Today’s air conditioning units are built much differently. Units are built to be just big enough, their coils are not oversized and their compressors are barely large enough. This all makes the efficiency rating of units higher, but also means the charge of refrigerant has to be within 2 ounces of the correct amount. Unlike the old days, air conditioners require a much higher level of precision.
The mantra of “beer can cold” is not only outdated, it was truthfully never a helpful or accurate reading to begin with. Here at the Training Center of Heating and Air Conditioning, we teach our students how to use the advanced techniques and tools at their disposal to do the job and charge the air conditioners they work on the right way, leaving “beer can cool” where it belongs: In your hands after a hard day’s work and you are relaxing at home in your hammock.
Learn more about enrolling in upcoming classes at the Training Center of Heating and Air Conditioning here.