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How to Know if you May Have an HVAC Emergency

Emergency HVAC repairs or service during the hottest or coldest days of the year is one of those things you hope you never have to deal with. So, as they say, (and as we say!) prevention is the best medicine. Check out our article on preventing HVAC emergencies (insert hyperlink) before they make you sweat (or shiver). 

Sounds and smells are often the biggest tip-offs that you have a problem with your HVAC system needing immediate attention. And unfortunately, HVAC emergencies aren’t something you can tackle yourself. Fires, carbon monoxide leaks, or even explosions may occur. This article lists many signs of an emergency that should prompt you to call an HVAC professional right away.

This article also discusses some possible causes for HVAC issues or problems you might be seeing with your system. 

Noises: HVAC is Turning on Too Often, or Making Odd Sounds

Your HVAC system’s cycles–turning on and off to maintain the desired temperature in your home–should be consistent and regular. One thing you may hear is your system turning on and off more often. While cycles can shorten when it’s extremely hot or cold outside, this can also be a sign that something is wrong. Sometimes it may indicate a problem with the thermostat or the unit needing other service; or it could be that something is seriously wrong with the entire HVAC system. A thorough check by an HVAC professional can often target the source of the problem and prevent other issues from cropping up.

Odd sounds are probably the most obvious sign that your HVAC system is struggling. 

  • A rattle could mean an internal part has gotten loose and needs tightening. 
  • A grinding or higher-pitched shrill sound could mean your motor or compressor has a problem.
  • A rhythmic knocking sound could mean something is stuck to the internal fan or there is another type of blockage inside your unit. 
  • A normal but overly loud unit could mean there is a blockage in airflow. 

Of course, these sounds could also mean something else entirely. While some of these situations are more urgent than others, it’s important to make sure the noise isn’t a technical issue putting you or your family in danger or doing damage to your unit if it continues. If you hear odd noises, get it checked by an HVAC professional.

Vents: Hot Air, Smelly Air, or No Air Coming Out 

When the AC is on, the air should be cool, not warm or hot. Some culprits for warm air are:

  • dirty filters, 
  • lack of airflow, 
  • electrical issues, 
  • a thermostat issue, 
  • evaporator coils that have frozen… among others. 

If you notice a warm air problem, you might consider checking the thermostat temperature, and turning down the thermostat to see if your HVAC system responds as it should. If the air does not cool off, you should call an HVAC professional.

Smelly air is another problem. 

  • A burning smell could indicate a motor that’s overheating, a potential fire, or a melted part inside the system. 
  • A mildew smell could indicate mold growing somewhere inside your HVAC system or inside your vents. 
  • Rancid smells could indicate a rodent or small animal has gotten inside the unit or vents and died. 

These are just some of the smells you may notice, but if there is a bad smell in your home, take a sniff of your vents. If you think there’s a possibility the odor is coming from your HVAC system, your next step should be a call to an HVAC professional. It’s also best to turn off your system if it’s not too hot or cold outside. However, if it’s a burning smell, turn off the system immediately and get a professional in quickly, so you can get to the bottom of the issue before more damage is done.

No air or lack of airflow coming from your air vents is another sign to watch for. This could be: 

  • a clogged fan or loose fan belt, 
  • motor issues, 
  • or a clogged air filter. 

Regardless of the cause, reduced airflow is another sign that requires immediate attention. You might also notice that certain areas of the house are not cooled or warmed– another indicator of a problem with airflow. It is possible that you’re just noticing how poorly your HVAC system and vents’ airflow is, which is not necessarily an emergency but something that an HVAC professional can assess. 

Ice or Water Where it Shouldn’t Be

A visibly frozen HVAC unit, or a unit with leaking and pooling water, can be indicators of:

  • dirty air filters or coils, 
  • refrigerant leaks, 
  • or blocked airflow. 

Your best course of action if you notice ice or water where it shouldn’t be is to call an HVAC professional, and if possible, turn off your HVAC system. If your system has frozen over, continuing to run it can cause bigger problems– like breaking the most expensive parts of the unit and needing an entire HVAC unit replacement. While leaking or even freezing aren’t uncommon, they are issues that need immediate attention to avoid further damage.

Is it an Emergency or Not?

Smells, sounds, leaks, freezes… these are indicators that something has gone wrong. Is it an emergency? Will your entire system be compromised or will your house burn down if you don’t get someone in ASAP to check it out? Because it’s not possible to answer these questions or diagnose the issues without a professional assessing your HVAC unit, it’s best to err on the side of caution. 

If your HVAC system shuts down or you smell burning or otherwise unbearable odors, paired with temperatures outside that require heating or cooling, this certainly would be considered an HVAC emergency. If you can, turn off your HVAC unit and make the call to a professional right away.

Call us 

Exxel Mechanical serves a wide area of central Maryland from our home base in Mount Airy, including WestminsterOwings MillsEllicott City, and Frederick. Our reputation in this area precedes us, as we pride ourselves on placing our customers as our highest priority. This means we not only care about saving you money, but we also care about your safety. If you think you have an HVAC emergency, call us immediately and we will send someone out to check on your HVAC system!  Call us today at (443) 821-1040 or email