What Does Freon Smell Like?

What Does Freon Smell Like?

Freon smells sweet to me. I’ve dealt with several refrigerants in my career and I can’t say the I’ve noticed any difference in smell between them. When compared to my wife though, I have a terrible sense of smell.

Amongst the types of Freon I’ve delt with are, R22, R11, R500, R410A and several others. The “R” stands for refrigerant. Freon is a brand name. Like Kleenex is to tissue, Freon has become a generic name for refrigerant.

R410A is what is used in modern HVAC equipment and R454B is coming out to replace R410A. All in a effort to protect our environment. When people ask Google what Freon smells like the answers are crazy different.

  1. ammonia
  2. gas
  3. cat urine
  4. paint
  5. chlorine
  6. sweet
  7. acetone
  8. propane
  9. rotten eggs

The sweet smell is the only one that I can relate to. but you and I are going to smell the same thing and have a different reactions as to what that refrigerant smells like. All the way from ammonia to rotten eggs. Read the following quote.

But what the researchers found is that no two people smell things the same way. “We found that individuals can be very different at the receptor levels, meaning that when we smell something, the receptors that are activated can be very different (from one person to the next) depending on your genome.”


When we’re on road trip and pass a dead skunk we will all probably say that was a dead skunk. But that was our own personal identifier to what a skunk smells like. If we had to describe what that skunk smell was like, we’d probably have descriptions that ranged from ammonia to rotten eggs.

Yet, all we can do is compare what things smell like with what we know of other smells.

This is really beginning to be interesting. I thought I should do some research of my own. I know lots of people that have smelled refrigerants, not in a huffing way.

Bobby said “Musty, I guess, I try to never breath it, Ha, Ha, Ha.”

Nick got back to me right away and his answer was that Freon has sort of an oily smell kind of like used motor oil. And he said “no, I don’t think R22 and R410a smell different”. Nick thought it was a hard question to answer.

My son sells HVAC in Alabama so I texted him and he said ” I don’t know, I’ve never smelled it, but I just asked 42,000 people on Facebook’s HVAC Pro Talk group. I had to join to find out they’re answers, but I haven’t been accepted yet.

I’ll update this later with some of the answers.

Just got a few of the answers. Wow what a concoction of wild smellers.

  1. R22 smells like a fresh bag of chlorine for pools.
  2. R134a smells like garlic
  3. R404a smells like copper
  4. R290 smells like Vick’s vapor rub
  5. Green apples
  6. Bananas
  7. Vinyl band aids
  8. Old Rubbermaid container

Crazy, huh? I didn’t know copper had a smell, And bananas? Like I said, my son sent the question out to 42,000 Facebookers and I just quit at eight answers, Enough to prove a point. We all smell different.

What Is Freon?

Freon is a gas at room temperature and a liquid when cooled or compressed. Freon gas is colorless, non-flammable and relatively odorless. Some Freons have an ether-like odor.


When most people inquire about smells in cars or what does Freon smell like in house, the likelihood of the odor being Freon or refrigerant is very slim. Refrigerants are 4 times heavier than air and linger to the floor.

As a comparison, natural gas is lighter than air and propane is like refrigerants, it is heavier than air.

Refrigerants also have a high volatility rate meaning that they vaporize quickly or will not stay in a liquid form unless pressurized. R11 is an exception to that because it vaporizes or boils at 74.7 degrees F.

Which means it will be in a liquid form with out being pressurized until it gets hotter than 74.7 degrees F. But R11 is not in anything you would likely own.

So what does Freon smell like when it leaks? Your guess is as good as mine, or as bad as my smeller.

Is Freon Dangerous To Breathe In?

Despite what we’ve covered here and all the opinions of what Freon smells like, Healthline says that “Freon is a tasteless, mostly odorless gas”. Indiscriminate amounts of refrigerant that get inhaled are mainly harmless, thank goodness, since that occurs quite often in just bleeding refrigeration hoses.

Refrigerant poisoning is not an frequently occurring event, except in cases of abuse. Huffing, or inhaling Freon in an attempt to get high. These chemicals can give the inhaling person what’s described as a pleasurable feeling.

I had a customer call that had a heat pump problem. When I checked out his system I found it to be completely flat or out of refrigerant. I pressurized the system with nitrogen and found no leaks. I drew a vacuum and still no leaks.

This was a rental for my customer and he knew a relative of the renter and suspected him of huffing the Freon from the system. Or he could have just dumped it out of meanness or retaliation for something.

Recent codes have made it a requirement to add locks to the service ports of new installations. But homeowners that want to protect their valuable refrigerant from being stolen by some huffer can easily install these locks on there own systems.

You can get a look at these locks on Amazon.

If you have a heat pump then you will need three locks. Air conditioners will only need two. As you can see you get your own key. Just remove existing caps and replace with these locks and tighten with the key.

Rap Up

So pick your poison. Freon can smell like anything you will imagine, but don’t go out and take a whiff. There’s enough evidence here to know that Freon has a smell and it’s not important enough to prove your smeller is the correct one.

Chad Peterson

Chad Peterson is near 40 year veteran of the HVAC industry. "I like to explain heating and air conditioning problems in a way the average home owner can understand. "

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