We’re finally heading towards the end of the cold season, and before you know it you’ll be firing up your AC unit again. Everyone always hopes that their unit will kick back into gear without a hitch, but of course that’s not always the case. There’s also a possibility that your unit will start out the season working fine, only to suddenly stop blowing cool air in the middle of August. Proper AC unit upkeep makes a big difference in your unit’s longevity, but inevitably an issue will arise eventually. And when something does go awry, it’s important to be aware of common issues that can occur with AC units.

This article will go over the most common hallmarks of a malfunctioning AC unit and the problems they often point to, how you can troubleshoot your AC unit at home, and when to call a pro about an issue. How can you know whether your AC unit needs to be repaired or replaced? Read on to find out.

Signs You Need to Repair or Replace AC Unit

When something is going wrong with your AC unit, in many cases early detection and repair will make a big difference. Often, smaller issues grow into larger, costlier problems over time. AC issues vary in severity, with some being easy repairs, while others pretty much spell the end of your unit.

Here are the biggest signs that your AC unit is in need of repair, or in some cases replacement, and their associated issues:

Your AC unit isn't blowing cool air

This is the most obvious symptom that a malfunctioning AC unit will exhibit. This can be caused by several different issues within your unit’s machinery:

• Your compressor (the part in your outdoor unit that is responsible for cooling the air) isn’t functioning properly.
• Your unit is low on refrigerant. An AC unit can be low on refrigerant for 2 reasons: either there wasn’t enough refrigerant put into your system when it was set up, or the refrigerant lines have sprung a leak.
• There is a tear in your ductwork.

Weak airflow out of your vents

If your AC unit vents are hardly blowing any air at all, that means there’s likely some sort of issue with your compressor or ductwork.

Your unit is emitting strange and/or loud noises

Any grinding, screeching, or banging noises from the outdoor unit, or a high-pitched hissing noise from the indoor unit all spell trouble. Some common noises and their causes are:

• Squealing or metal-on-metal screeching noises coming from the outdoor unit are normally due to a worn-out fan or fan belt, meaning the fan will likely need to be replaced.
• High-pitched hissing tends to signal high-pressure buildup within your cooling system, which can be quite dangerous. Hissing could also mean there’s a leak in your refrigerant lines or your compressor valve. In any case, if your unit is suddenly making a screaming noise, turn it off immediately and call a professional.

Your thermostat isn't working

Your thermostat senses the temperature in your home and adjusts accordingly. If your AC unit isn’t turning on at all, or only running for short periods of time and then shutting off, it could be due to an issue with the thermostat, or the electrical wiring connected to it.

You're noticing an odd, unpleasant odor coming from your AC vents

If the air coming from your AC vents smells musty, this could mean there is mold growing somewhere within your system. Breathing in mold spores isn’t healthy, so this type of issue needs to be handled promptly. And if you’re smelling something burning, there may be an electrical or insulation issue. This should also be looked at by a professional.

Sudden, unprecedented spikes in utility costs

Of course, increased AC usage leads to higher bills, but if your bill is far higher than anticipated based on how much it normally costs during the summer, it could signal a problem with your ductwork or thermostat.

Moisture leaks in or around your unit

In some cases, leaks may just be a leaky condensate line, which is not too serious. However, if you notice the leak is a yellow-green liquid or another odd color, call a professional immediately as this means you likely have a refrigerant leak. Though refrigerants are normally colorless and odorless, they are blended with a refrigeration oil that tends to be tinted green. If you’re noticing a dirty, possibly greenish, oily substance leaking out of your unit, call a professional.

The age of your unit is also a contributing factor in how viable a repair is. The average lifespan of an AC unit is about a decade, so if your unit is on the older side and you’re noticing a drop in functionality, it may be time to look for a replacement. Replacing an AC unit can carry a high upfront cost, but in the long run it will be cheaper to get a new one than to keep repairing an old, failing one.

How to Troubleshoot AC Unit, and When You Should Call a Pro

There are some ways you can inspect your unit in order to determine what’s wrong with it. However, if you think your unit’s issues are caused by a refrigerant leak, do not attempt to fix it yourself. The chemicals used for refrigerants are hazardous to both your health and the environment, and should only be handled by a professional. Besides a lack of cool air and oily leakage around the unit, another telltale sign of leaking refrigerant is a bubbling or hissing sound coming from the outdoor unit when it’s not running.

All that being said, if you find your unit isn’t working properly and you don’t think it’s a refrigerant leak, you can try and diagnose the issue by inspecting your unit for noises and leaks and taking a peek at your ductwork. Below are some issues you may be able to remedy on your own:

• If your AC won’t turn on, it could simply be a problem with your circuit breaker. Head to your circuit breaker box and see if the breakers connected to your AC unit are tripped. If you flip them back to “ON” and they immediately switch “OFF” again, or the circuit being tripped becomes a persistent issue, you’ll need to call a pro, as it’s likely an electrical issue.
• If your AC unit isn’t cooling as well as it should, it could mean that your outdoor unit is dirty. Check out our blog post on AC maintenance for tips on how to clean your outdoor unit. Decreased cooling efficiency could also mean it’s time to change your filter. If your unit is still not working properly even after you’ve cleaned your unit and changed your filter, it’s likely an issue with your machinery or ductwork and you’ll need to call a pro.
• If your unit is making a clicking noise as it runs, check the fan of your outdoor unit. There may just be a small object like a pebble partially obstructing the fan. Turn the unit off and inspect the fan for anything stuck in the path of the blades.

In some cases, you may be able to fix the problem yourself, but in the majority of cases it’s likely you’ll need to get a pro involved due to the complex electrical wiring and machinery involved in an AC system.

Regular Maintenance is Key to Avoiding AC Issues

Yearly checkups by a professional and cleaning your AC unit at the start of each cooling season will keep your unit running without issue for as long as possible. But besides your yearly tune-up, there’s one more easy task that you can perform that will increase the longevity of your unit: changing your filters on a monthly basis. A clean filter will allow your unit to run at optimal efficiency, meaning it will use less electricity. It will also help you avoid putting strain on your system, which can result in the need for repairs down the line.

Shop our range of AC filters today to keep your AC unit going strong. And if you’re unsure about which filter is right for your system, get in touch with us today; our team of HVAC experts would be happy to assist you!