Pee-yew! Why Does My AC Smell Like Urine?

Dust-Laden Air Filter

If you haven’t cleaned your AC’s air filters in a while, now is the right time. Unfortunately, most AC owners neglect to clean the air filters. Not only does this causes a foul ammonia-like smell, but it also compromises the air conditioner’s performance.

Fix

Properly cleaning the air filter will eliminate the dust and debris accumulated on the filters. As a result, your AC will give off fresh and pleasant-smelling air. Here’s how to go about it.

• Turn off the power. It’s always better to switch off the air conditioning unit when trying to service it. Not only does it allow for easier cleaning, but it also ensures your safety.
• Use a vacuum cleaner. Directly soaking the dust-laden filter won’t give you the best results. Therefore, consider using a vacuum cleaner to blow the dust caked onto the air filters.
• Soak the filter. Once the visible dust comes off, it’s time to soak the filter. Mix a 50/50 solution of water and vinegar into lukewarm water in a large basin. Now dip the air filters and let them sit for at least 20 minutes. Then, gently scrub the filter using your fingertips (you can wear gloves to be more comfortable).
• Let it dry. After giving a thorough wash, let the filters dry completely.
• Reinstall it. Place the filters back into your AC. Most of them have an arrow pointing toward the direction of installation. So, you’ll figure out the correct installation method.

Ammonia Emitting Bacteria

Another gross reason behind the urine-like smell from your AC is the infamous ammonia-emitting bacteria.

Research conducted by Dr. Lai ka-man and his team at a Hong Kong University discovered several bacteria species that feed on dead skill cells and organic debris.

So, when we shed the dead skin cells (skin squames), the tiny bacteria feast on them for breakfast, lunch, and dinner. These bacteria can, unfortunately, reside in your air conditioner.

So, upon digesting the protein from your skill cells, they emit a nasty ammonia-like odor.

Fix

The only way to keep your unit from emitting nasty smells is to maintain it regularly. Consider cleaning your air conditioning unit, as mentioned in the previous section.

If that seems too much work, you can always call a professional for regular AC upkeep.

Engine Oil Fumes or Coolant Combustion

Another reason your car AC may smell like pee is the exhaust fumes from engine oil and burning coolant. Although fumes typically eliminate a burning smell, if the ventilation system and the engine oil aren’t compatible with the vehicle, they may smell like ammonia.

As with other car parts, the ventilation system gets affected and deteriorates after a certain period. So, when the system gets damaged or has an underlying problem, it emits an unpleasant odor, impairing your well-being.

Fix

The only way to eliminate the nasty pee-like odor from coolant combustion is to contact a professional. They’ll thoroughly inspect your car, spot the precise problem, and take a solution accordingly.

Mold Buildup

Mold is one of the common causes of an ammonia-like smell coming from your AC. The notorious mold spores exist naturally in the environment and tend to grow as soon as they find a damp or moist area.

Refrigerant gas has natural levels of moisture. But how does it accumulate mold?

Air conditioning systems use the air from inside your home (or car) and cool it down using a refrigerant. This means your air conditioner sucks the indoor air and the pollutants within it. As a result, mold can buildup. Unfortunately, mold exposure can lead to health issues such as:

• Fatigue
• Runny nose
• Itching
• Sneezing
• Coughing
• Watery eyes
• Trouble breathing

To reduce the impact of mold on your health, you need to remove it quickly.

Fix

Follow the steps below to remove mold from your air conditioning unit.

• Remove the AC’s outer case to expose the coil, fans, and compressor
• Blow compressed air to remove the dust particles (make sure you do so from a distance to avoid damaging the delicate internal components of the AC)
• Use a soft-bristled brush to clean the finer dust particles in the front and back of the system.
• Use a homemade cleaning solution – ideally baking soda and vinegar – to clean the duct and vent.
• Pour water to clean out the solution.
• Clear off the debris by flushing out the drip tray (avoid applying excess pressure)
• Let the unit dry completely before turning it on
• Reassemble the machine and enjoy the fresh air

Clogged Evaporator Coils

Over time, your AC accumulates soil, bacteria, dust, and germs on the evaporator coil. As a result, the AC starts smelling bad when turned on. You can unclog and clean the evaporator coils to eradicate the urine-like smell.

Fix

Follow the steps below to get started with the cleaning process.

• Turn off the AC system. Flip the toggle switch to turn off the power. If you fail to locate the toggle switch, you can always turn off the electricity at the circuit breaker.
• Uninstall the access panel. Use a socket wrench or a screwdriver to remove the panel.
• Find the evaporator coils. The evaporator oils are generally located on the air intake side of the fan. They are made of steel, copper, or aluminum and feature tubes bent in a U-shaped pattern and adjusted into the panels’ frame. The panels are lined with thin aluminum pieces called fins.
• Get your hands on a pump sprayer and a cleaning solution. A professional alkaline solution is ideal for removing dirt and debris from the evaporator coils. Follow the label instructions to prepare the cleaning solution, and use 3.8 L (1 US gal) of spray to clean the coils.
• Brush the coils. Light brush strokes will loosen the leftover dust and clean the evaporator coils adequately.

Reinstall the access panel and seal it using HVAC tape. Turn on the AC, and the urine-like smell would likely dissipate.

If you’re dubious about your DIY skills, you can always contact a professional for AC maintenance.

Pests

Household pests may be contributing to the urine-like smell of your AC without you even knowing it. For example, vermins and rodents might mark their territories in your home or car AC, causing it to smell like pee.

Even worse, some rodents and animals crawl into your AC vents during winter. Over time, they expire, and the decomposing organic matter emits a urine smell which you may sell every time you turn on your AC.

Fix

Here’s how to remove a dead animal from your AC vents.

• Wear protective gloves and take a plastic bag before opening the AC vents
• Open the barrier and pick up the decomposing body of the animal
• Carefully place it in the plastic bag and discard it (be sure to throw away your gloves too)

Following this, use a disinfectant spray to ward off the nasty smell. This would also make up for an ideal solution if a rodent or another animal relieved themselves on your air conditioner.