FAYETTEVILLE, Ark. (KNWA/KFTA) — According to Paschal Air, Plumbing and Electric, when you’re running your air conditioning unit more often and at colder temperatures, it is more likely to freeze up.

If you notice something wrong with your AC, especially visible ice, it’s time to take action. Other than visible ice on any part of your HVAC unit, the next most obvious sign of a frozen AC unit is a lack of cool air. If you put your hand in front of your supply vents and you sense warm air coming out, you probably have ice somewhere in the system, according to Paschal.

You may also notice a hissing sound coming from the unit. If that’s the case, take steps immediately to prevent further damage. Your air conditioner might take anywhere from an hour to more than a day to completely defrost.

It’s important to catch problems early to prevent further damage to your unit—and, of course, so you’re without cool air for the shortest amount of time possible. Here’s a step-by-step defrosting guide:

  • 1st Step: Turn Your HVAC Unit Off. Running a frozen air conditioner will wear out parts much faster, and could overheat your unit. Worn parts are bad news for the most expensive piece of your HVAC unit—the compressor. To avoid lasting damage and a hefty bill, turn your air conditioner thermostat located inside from COOL to OFF. This will start the defrosting process. 
  • 2nd Step: Switch Your Thermostat Fan to ON. Turning the HVAC fan to ON will force it to blow warm air over any frozen coils—which will speed up the defrost process. Make sure it’s actually set to ON and not to AUTO. Automatic settings cause the fan to cycle—starting and stopping over and over again. There is an option on your indoor thermostat to do this.
  • 3rd Step: Locate the Source of the Problem. What caused your air conditioner to freeze up in the first place? There are a few common culprits, including dirty air filters, dirty evaporator coils, leaking refrigerant and other problem parts and issues.

Clogged-up air filters will essentially suffocate your air conditioner unit. When warm air is restricted from the coils in your unit, the coils get too cold and eventually ice over. Replace air filters at least once a month to prevent an icy surprise.

If your coils are pretty dirty, the same process always occurs. Dirt, dust, debris and grime covering the evaporator coils cause massive air restriction the same way dust will in your air filter.

If you spot a refrigerant leak anywhere, that’s probably going to be the main cause of your ice problem. Low refrigerant levels cause drops in pressure, allowing moisture in the air to freeze around your HVAC coils.

Despite what many homeowners may think, refrigerant doesn’t simply get “used up.” It doesn’t decrease over time, and it doesn’t evaporate during AC use. So if you’re low on refrigerant, there’s absolutely no doubt you have a leak, according to Paschal.

A collapsed duct, weak blower, or closed valves might be causing your air conditioner to freeze. Air conditioner units are very complex machines with a lot of other pieces and parts. Our Northwest Arkansas, Fort Smith River Valley & Southwest Missouri HVAC pros can help to diagnose these less obvious problems.

As your air conditioner unit thaws completely out, you might run into some additional damage. Drain pans that have overflowed and clogged condensation drains are a large risk when this much water is coming off your air conditioner. Place some towels around the unit and watch for any additional leaks to prevent water damage. 

Once your air conditioner unit is completely clear of all ice and all parts are dry, you can turn your A/C back on. Keep a close eye on the unit for any continued problems over the next several hours to a few days.

Can I Pour Hot Water On Frozen Air Conditioner? The answer is “Yes”. Pouring hot water will melt the ice faster and in turn, thaw your AC faster. In fact, the water does not need to be extremely hot. Even warm water or running water will work to thaw the ice.

If changing the air filter solved your ice problem, you’re in luck. Getting regular preventative maintenance and inspections can help catch issues early and prevent your air conditioner from freezing up.