Signs an Air Conditioner Needs to Be Repaired (Or Replaced)

The summer season is officially in full swing, which if you own a heating and air conditioning company, you’re probably already well-aware of. It’s likely that if you’re in the business of repairing and replacing air conditioners, you’ve already seen a big uptick in business.

Often, customers don’t realize they have an issue with their air conditioner until it’s become pretty significant.

If you’re an A/C professional, it’s good to help your customers understand the red flags that maybe their system needs to be tuned up. This can help them avoid having to replace it as soon.

The following are some of the signs to convey to customers as far as when an A/C unit needs to be repaired and also when it needs to be replaced.

Strange Smells

You want to make it clear to your customers if you work in heating and air that strange smells shouldn’t be overlooked.

If you’re not a heating and air professional and you notice that your unit seems to smell strange lately, call a professional.

Weird smells coming out of vents when running central air might mean that either repair work needs to be done or a replacement is needed.

The air should smell clean and never moldy or musty. It shouldn’t smell smoky either.

If an AC unit is emitting a smell similar to car exhaust, it could mean that there’s a refrigerant line leak. Any chemical smell is something you need to reiterate to clients that they should contact you about right away.

What if an AC unit smells like something is on fire?

In this case, it could be that dust has settled in the unit, or it could mean that parts in the unit are actually burning. Anytime there’s a fire or smoke smell, customers should turn their unit off right away and wait until you can go to repair it.

The smell of rotten eggs wafting from an air conditioner could mean a dead animal got stuck inside.

A moldy or musty smell is the most common of the odor issues, and usually, it just means that water has accumulated in the drip lines or drain pan. That can lead to the growth of mildew or fungus. A musty smell could also mean the filters are dirty.


In the spring and summer, humidity outdoors is normal—in some locations more than others.

High humidity indoors is not normal, however, if you’re running your A/C.

One job of an air conditioner is to remove humidity in the home. There’s the evaporator coil responsible for taking warm air out of a home, cooling it, and then pushing it back in. Moisture is removed during this process, but it could leak outside of the unit. That’s why you see the drips from a unit sometimes.

As an AC gets older, it becomes less efficient.

Then, that can lead to evaporator coil issues, so it’s more difficult for an air conditioner to remove humidity from inside.

Along with air that feels more humid, homeowners might see fog on their windows or moisture gathering around their vents. This can then lead to the development of mildew or mold, which can create a whole other set of problems.

Limited Air Flow

One of the most obvious signs that something is amiss with an air-conditioner is if the airflow is weak or non-existent from the vents.

If there’s an airflow problem, it could mean there’s a specific issue with the air ducts or the compressor.

Additionally, it’s, of course, a red flag if a home is just too hot even with the air conditioner running. The air conditioner might be removing some heat, but on very hot days especially there may just be a general feeling that it’s not keeping up.

Warm air might even blow out of the vents sometimes, even when the air conditioner is on cooling mode. This could be a problem with the compressor.

Strange Sounds

Along with unpleasant odors, strange sounds coming from your AC might be a problem.

For example, if there’s clicking from the outdoor unit when it’s running, that might mean something is blocking the fan partially.

If the unit is clicking and won’t turn on, it could be an electrical problem.

If an air conditioner makes a gurgling sound, it could be due to a refrigerant leak. If you hear a banging sound coming from the outdoor unit, the fan might be hitting something.

The sound of metal on metal could mean the fan bearings are going out, and a high-pitched scream or hissing sound is probably from the compressor.

If you hear squealing from the indoor unit, it could be a fan belt problem.

Rising Utility Costs

Customers should be aware that rising utility costs might mean they need to take a look at their air conditioning and how well it’s functioning or possibly not functioning.

If the power bill suddenly goes up and there’s no other identifiable reason during the summer, it could be a good time to have someone take a look at the unit.

The System Is Old

If a customer has a unit that’s older than a decade, then it might be getting to its replacement point.

Customers need to understand that ten years is the life expectancy of a quality air conditioning unit, and not replacing it if it needs it at that point is going to be more expensive in the long run.

If you’re frequently visiting the same customer time and time again, you should educate them on the fact that frequent repairs are a sign they need a new unit. You should go over the cost of repairs versus the cost of a new unit with them and help them understand what’s going to make the most financial sense in their situation.

You should also advise customers whenever possible not to try and DIY repairs on their air conditioner.

They’re complex machines, and they need to be treated as such.

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