What To Check When Your AC is Running But Not Cooling

It’s almost summer, and the temperatures are rising. Finally, you make the switch! You close all the windows and turn on the air conditioner. But something’s wrong! Your AC is running but not cooling.

You hear the unit working. But, there’s no air coming through the vents. Or, maybe there is, but the air is warm.

There are a few possible explanations for this problem, and we’re outlining the most common ones in this article.

You can check a few of these on your own, and even take care of a couple of them yourself. After that, you’ll need to call for an AC repair..

Wrong Thermostat Settings

Start by checking your thermostat. And, don’t feel embarrassed if the problem turns out to be simple user error. It’s more common than you think.

You may have your system on “Fan Only.” Or, it’s switched to “On” instead of “Auto.”

The fan is a useful setting when you only want to circulate air in and out of the house without adding heat or cooling. It improves your indoor air quality, especially when the pollen count kicks up in the spring. But, it won’t bring down the temperature.

All you’re doing is running the fan. Your intake vents are drawing stale air and sending it outside. Meanwhile, the system draws in fresh outdoor air and circulates it in the house. But that’s it.

To get the air conditioning, which includes cooling and dehumidification, you need to set your system to “Cool.”

It doesn’t matter if you change the temperature setting. If it’s on fan only, you’ll hear the system running, but the AC won’t kick on.

Clogged Air Filter

Next, check your air filter. Has it been a while since you changed it? If so, you may have found the problem.

The air filter, as we’ve covered here and here, helps keep your air clean. It does so by trapping dust, dirt, and other small particles in a screen as they pass through your HVAC system.

However, it’s important to change it often. We’ve seen places advise people to get a new one once every three months, or each season as an easy way to keep track.

But, we recommend changing out that filter every month. They’re pretty cheap — basic ones are under $10 — and it helps keep your air clean.

The other advantage? It keeps your air conditioner running well.

Here’s what happens otherwise: Over time, your filter becomes clogged with all the junk it’s collected. At that point, it doesn’t only trap specks of dust and other pollutants. It also prevents air from passing through.

You know, what you want circulating through your house.

At this point, if it’s in the summer, you’ll hear the AC kick on. But, you won’t feel its effects.

That’s because the air it’s trying to pump into your home never makes it. Or, very little manages to seep through, but nowhere near enough to make an impact.

Ice on Your Air Conditioner

If you’ve ever seen an air conditioner with ice on it, a clogged filter is probably the reason for it.

When the unit’s airflow is constricted, the evaporator coil becomes very cold. When it drops below freezing, the humidity — or water vapor — around it starts to freeze.

Then, the ice builds up over time until you can see it from outside the unit. The other possibility is low refrigerant. But, either way, it’s a significant problem.

So, turn off the system and call a professional if you notice this happening.

Refrigerant Leak

A lack of refrigerant can also cause your AC to run without cooling. It’s also the other main culprit behind an icy air conditioner.

In this case, the air is passing through the system like normal. But, without any refrigerant, you’re missing the actual “cooling” part of the cooling process.

Typically, heat gets transferred from the air to the coolant. With a leak, that warm air flows right back into your home.

That’s why you hear the system working and even feel the air through your vents. But, the air you feel is still warm.

You won’t see a leak, but you may hear or smell it.

Head out to the outdoor condenser. Listen for hissing — the sound of gas escaping. That could be the refrigerant., especially if you’re noticing a lack of cooling and ice on the unit.

There also may be a chemical or ozone smell. In that case, you’re picking up whiffs of the coolant as it escapes the system.

Once again, shut down the system and call your HVAC company. They need to fix the leak and recharge your system.

Dirty Or Broken Compressor

The compressor circulates the refrigerant through your system. And, as discussed, the refrigerant is how heat escapes from the system, so the air that returns to your home is cool.

But, if there’s a problem with the compressor, this crucial step doesn’t happen. Then, once again, you’re left with an AC that’s running but not cooling your home.

Often, the problem is just that the condenser coils around it are dirty. Or, the piece itself is failing.

To start, check out the fins on the outside of your system. Your system may not work correctly if the fins are broken, bent, or dirty.

Next, listen for odd noises from inside the system. Anything other than the usual shake or stutter when it kicks on could be a problem. The tell-tale sign is usually a jarring “hard start” sound.

The outdoor unit may also be overheating or getting warmer than usual. These signs all indicate a compressor problem.

Air Conditioner Service Repairs in Havertown, PA

If the air conditioner in your Havertown, PA home is running but not cooling, call us here at John Cipollone. With more than 50 years in the business serving Delaware and Montgomery counties, we’ll get to the bottom of the problem fast and have you feeling comfortable again in no time.