(651) 228-9200Schedule

All Articles

How to Tell if Your Air Conditioner Needs More Refrigerant (Freon)

We get this question from Minneapolis homeowners a lot—especially right before summer:

“How do I know if my air conditioner needs refrigerant?”

First of all, in a perfect world, your air conditioner should never need more refrigerant. Refrigerant isn’t used up like gas in a car.

So you only need more refrigerant if there is a leak somewhere. And to know that for sure, you need an AC technician to measure the amount of refrigerant in your air conditioner. (This is one reason a yearly maintenance visit is a good idea.)

But there are some signs that can clue you in. Here are 5 things to look for that might tell you that your AC needs more refrigerant.

Your AC runs all day and never cools your home

The refrigerant in your air conditioning system is responsible for absorbing heat from your indoor air and then dumping it outside.

If your AC is low on refrigerant, it can’t absorb as much heat from your home. And that leads to an air conditioner that runs nonstop and never cools your home.

And that can cause...

High energy bills

As your air conditioner runs nonstop to try to cool your home, you’ll be racking up a huge cooling bill. Of course, that sky-high energy bill could be caused by something else (like closing your air vents).

So before jumping to conclusions, look for some of the other signs on this list, like...

Air coming out of vents isn’t very cold

Without enough refrigerant, your air conditioner won’t be able to absorb as much heat from your home’s air. That means the air blowing out of the vents will feel warmer than normal.

In some cases, there may also be less air blowing out of the vents.

An air conditioner without enough refrigerant can literally freeze and turn into a big block of ice. The ice on the inside of the air conditioner blocks the airflow, reducing the amount of air that comes out of the vents.

And speaking of ice…

There’s ice on your refrigerant lines

Walk outside and take a look at the refrigerant lines. Is there ice on them?

ice forming on refrigerant lines

Ice forming on refrigerant lines from low freon charge. Image Source: Knoji

After your inside AC freezes from low refrigerant, the ice can build up all the way to the outside unit along the refrigerant lines. Of course, by this time you should also have the symptoms above.

Hissing/bubbling noise

Most refrigerant leaks are silent because they’re pretty small. But a large leak can cause your air conditioner to make a hissing or bubbling noise when it’s running.

Note: Don’t forget to fix the leak

Don’t let an AC contractor just “top you off” with refrigerant. Remember: if your air conditioner is low on refrigerant, it’s leaking somewhere. If you just refill it, you’ll be low again soon.

A good AC tech will let you know that you have a leak and offer to fix it. Some companies don’t do that though because they’d rather just charge you to keep coming back and filling up your system.

Plus, doing it the right way is time-consuming. Fixing a refrigerant leak involves:

  1. Removing all the refrigerant from the system (called evacuating the system)
  2. Finding and fixing the leak
  3. Testing the fix
  4. Refilling your air conditioner with the right amount of refrigerant

Think you might have a refrigerant leak? MSP can find and fix the leak for you and get your AC back to working order. Contact us online.

Minneapolis Saint Paul Plumbing, Heating and Air has served the Twin Cities since 1918.