4 Common Air Conditioner Smells & How to Fix Them

Is your air conditioner releasing a bad or weird smell into your home? What does it mean, and can you fix it yourself? Below we walk through 4 common smells that might be coming from your air conditioner, what it means, and whether it is cause for concern. As with all HVAC questions or concerns, always call an HVAC technician if you are unsure!

1. Rotten Eggs

If you smell sulfur or rotten eggs, that almost always means there is a gas leak in your house. Natural gas is odorless, but gas companies add the smell so you know when there is a leak. The gas reduces oxygen levels in your body which can be fatal. It can also catch fire and explode. If you suspect a gas leak, turn off your gas supply immediately and call your local fire department.

2. Burning

If you just turned on your air conditioner for the first time in several months and it smells like something is burning, this could be dust burning. Wait a few minutes to see if the smell dissipates. If it does not go away, the burning smell could be a mechanical problem and a fire hazard. Switch off the system immediately and call an HVAC technician for an emergency repair.

3. Gunpowder

The smell of gunpowder is associated with electrical odors. This odor is very distinct and should never be ignored. It is likely caused by a fried fan motor or circuit board. No matter the culprit, you will need to get your AC repaired before using it again. Switch off the system and call an HVAC technician for a repair before turning on the unit again.

4. Mold or mildew

Smelling mold or mildew when your air conditioner switches on is quite common. When your air conditioner cools the air, condensation builds up and needs somewhere to go. If your condensate drain line is clogged, this moisture has nowhere to go, allowing mold and mildew to grow in the unit and in your ductwork. Shut off your unit and check the drain line and indoor AC unit for mold and mildew. You can unclog a drain line and clean an AC unit yourself, but if you have never done this before, we recommend calling a professional.


There are a variety of less-common odors that can come from your AC unit, including chemical smells, exhaust, or something that just smells terrible. Always turn off your unit if you think something is wrong and call for an AC unit inspection and repair. Allowing your unit to continue to run could be damaging the unit itself and be hazardous to your health.

Need an air conditioner inspection, repair, or replacement? Grand Home Services in Aurora, Colorado provides these services throughout the Denver Metro Area. Contact us online or call us today!

Why is my air conditioner leaking water?

Why is your air conditioner leaking water, and what are you supposed to do? Water leaking from your AC unit can cause a lot of damage, so it’s important you address the issue and fix it as soon as possible.

When your air conditioner cools warm air, condensation builds on the evaporator coils and drips into a drip pan. This drip pan leads to a condensate drain line that drains the water outside of your home, so you should not have any water leaking inside.

As with any home appliance, sometimes something goes wrong. For air conditioners, it is not uncommon for water to be leaking from the unit. Below are 3 common culprits that cause your air conditioner to leak water inside the home and what you should do to resolve the problem.

Your filter is dirty

If your air filter is very dirty, your air conditioner will have trouble pulling air through the filter and into the unit which means less air is moving over the evaporator coils. As a result, the coils become too cold and freeze. As these frozen coils defrost, the ice melts and an unusually large amount of water drips into the pan causing it to overflow and leak into your home. Make sure to replace your filter as often as the AC unit’s manufacturer recommends.

Your unit is low on refrigerant

When your air conditioner turns on, the refrigerant starts running through the evaporator coils making them very cold. If the refrigerant is low, there is less heat being absorbed and the coils get too cold and freeze. The refrigerant runs through a closed system, so if your refrigerant is low, this means there is a leak.

This is not something you can repair yourself. You should turn off the AC unit and call for a repair immediately. If you see that the coils are frozen, keep an eye out for leaking water while it defrosts.

Your condensate drain line is clogged

As your air conditioner creates condensation during the cooling process, it drains through the condensate drain line. If this drain line gets clogged, the water has nowhere to go and will leak from the unit inside your home. A clogged drain line can be caused by a dirty filter, debris in the drain line or lack of maintenance to the unit.

You can unclog the drain line yourself by turning off the unit and using a thin wire brush to break up the clog. You can also use your wet/dry vacuum to suck out any debris or flush the drain line with distilled vinegar. If you can’t get the drain line unclogged yourself, always call an HVAC professional!

Denver Air Conditioner leaking water?

Is your Denver air conditioner leaking water? Grand Home Services has seen this problem before and is here to help you solve the problem. We are located in Aurora and provide air conditioner cleaning, repair and replacement services throughout the Denver Metro Area. Call us at 720-365-1187 or contact us online to schedule an AC repair in the Denver Metro Area today!