5 Signs Your AC May Be Low On Coolant

Coolant is the blood of your air conditioner and without enough coolant, your AC can’t cool your home properly, leaving you sweaty and uncomfortable.

Not only that, but a low level of coolant can severely damage your air conditioner, just like a low blood count damages your body. We’ll explain why in more detail.

Here are the signs your AC is low on coolant and what you need to do to get things back to normal.

1) House takes forever to cool off

If your AC is taking longer than normal to cool the home, you may be low on coolant. Why? Because coolant is what absorbs the heat in your air. So without enough of it, your AC can’t absorb enough heat to cool the air well. In other words, think of coolant like a heat sponge: the smaller the sponge, the less it can absorb.

2) Supply vent is blowing lukewarm/warm air

If you’re really low on coolant, you’ll notice that your supply vents are blowing lukewarm/warm air. Now it makes sense why your home is taking forever to cool off!

3) Higher than normal electric bills

Due to lack of coolant, your AC runs much longer than needed to cool the home, increasing your energy bills as a result.

4) Ice buildup on coolant line

Go to your outside AC unit (the one with the spinning fan). If you see ice building up on the copper coolant line, then you may be low on coolant. When low on coolant, the inside AC unit’s evaporator coil (the part that cold coolant flows through) gets too cold, causing cold liquid coolant to flow back the coolant line. This causes the surrounding moisture on the coolant line to freeze up.

Oh, but there’s more. Eventually the liquid coolant will make its way to the outside unit’s compressor (the “heart” of your AC). This flow-back of coolant will damage the outside unit’s compressor. You see, liquids can’t be compressed, so when the coolant flows into the compressor, it’s quickly converted into thousands of pounds of hydraulic pressure, and something (valves, rods, plates) will break. Compressors are extremely expensive to replace and, if yours doesn’t have a valid warranty, you’ll probably end up replacing the entire outside AC unit since it’d be more cost efficient.

5) You hear a hissing/bubbling noise

The only reason you’d be low on coolant is due to a coolant leak (coolant isn’t used up like gas in a car, so escape through a leak is the only conclusion). And if you have a bad coolant leak, the coolant makes a hissing or bubbling noise as it escapes.

Next steps: How to fix this problem

If you suspect you have low coolant (and thus a coolant leak) call a professional AC technician for a diagnostic check. If they find a leak, they should repair it (if possible) before adding more coolant. Adding coolant without fixing the leak will cause the coolant to escape again, and you’ll have this problem all over again. And older R-22 coolant is super expensive now.

If you have any other questions about the coolant in your air conditioner, ask one of our experts for help.