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HVAC 101

What Does Refrigerant Do?

Refrigerant is the working fluid that makes air conditioning possible. It absorbs heat from your indoor air by evaporating into vapor, carries it outside, and releases it by condensing back into liquid, over and over, all summer long. It isn't a fuel and the system never uses it up, because the loop is sealed. If your refrigerant is low, it didn't get consumed; it leaked.

A Heat Shuttle, Not a Fuel

Refrigerant runs a closed loop between the inside of your house and the outside, and its cargo is heat. Indoors, at the evaporator coil, it arrives as a cold liquid and boils into vapor, and boiling soaks up heat, pulling it straight out of the air blowing across the coil. Outside, the compressor squeezes that vapor hot, and the condenser coil lets the outdoor air carry the heat off as the refrigerant turns back into liquid. Then the trip starts over. The trick is the phase change: evaporating absorbs heat, condensing releases it, and the refrigerant itself just keeps riding the loop.

That’s the part worth remembering. Gasoline gets burned up doing its job. Refrigerant just commutes.

”Low on Refrigerant” Always Means a Leak

The refrigerant circuit is sealed, brazed shut at the factory and at installation, and nothing about normal operation consumes what’s inside. So a system that’s low has a hole somewhere: a corroded coil, a rubbed-through line, a fitting that’s worked loose over years of vibration. That’s also why “topping it off” without a repair is a temporary fix by definition. The new charge follows the old one out, usually just in time for the meanest stretch of August.

Low charge shows up as weak or warm cooling, ice on the copper lines or the indoor coil, hissing near either coil, and run times that keep stretching. In a Gulf summer, when the system barely rests from May to September, a leak doesn’t stay hidden for long.

Three Generations of Refrigerant

Which refrigerant your system uses mostly depends on when it was built:

  • R-22. The standard in systems installed before 2010. It’s no longer produced, so keeping an old R-22 unit charged means drawing on a shrinking reclaimed supply, and a significant leak usually reopens the repair-or-replace conversation.
  • R-410A. The workhorse in most systems installed from 2010 through 2024. It remains fully serviceable, and nothing about the transition requires you to retire a healthy R-410A system.
  • R-454B. The new standard in equipment built since 2025, chosen for its lower environmental impact. If you’re shopping for a new system, this is what it will run on. Our R-454B guide covers the changeover and what it means for Louisiana homeowners.

DIY or Call a Pro?

Refrigerant is the one part of your air conditioner with no DIY lane at all. Federal rules require certification to handle it, and finding a leak takes detection equipment and gauges, not intuition. What you can do is notice things: ice where there shouldn’t be any, cooling that fades on hot afternoons, a system that used to cycle and now just runs. Those observations are half the diagnosis.

Ice, hissing, and cooling that fades by afternoon all point the same direction. Call us at (337) 893-5646 or schedule a repair: we’ll find the leak, fix it, weigh in the correct charge, and make sure it stays where it belongs.

Quick Questions

Does refrigerant need to be topped off every year?
No. The system is sealed, and a healthy one holds the same charge for its entire life. If a unit needs refrigerant every spring, it has a leak, and refilling it each year without a repair is renting a solution to a problem that's still there.
What are the signs of a refrigerant leak?
Weak or warm cooling, ice building up on the copper lines or the indoor coil, a faint hiss near either coil, and run times that stretch longer and longer. Charge level is one of the things we verify on a tune-up, which is how a small leak gets caught before an August breakdown.
My system uses R-22. Do I have to replace it?
Not while it's running well. But R-22 is no longer produced, so a major leak or a failed coil on one of those systems is usually the moment to weigh repair against replacement rather than chase scarce refrigerant. Our repair or replace calculator is built for exactly that decision.
Can my R-410A system be switched to R-454B?
No. Each system is engineered around one refrigerant, and the two aren't interchangeable. Nothing about the transition forces you to give up a healthy R-410A system, though: it stays serviceable. When the time for a new installation comes, the equipment will arrive designed for R-454B from the start.

Rather Have a Person Explain It?

Our technicians have been walking Acadiana homeowners through their systems since 1956. Call (337) 893-5646 or schedule a visit, and bring your questions.