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Why does my AC smell?

Imagine arriving home from a long and exhausting day, turning on your air conditioner and finding it is smelling really bad. Do not panic – there is a solution!

The most common reason that your air conditioner has an unpleasant smell is dirt and mould in the indoor unit.  Another main reason for the odour is not produced by the machine itself but by the drain, and the aircon is sucking it up and spreading the smell.

In the following article, we will tell you the main reasons for the bad odour and how you can solve it if it is possible, before considering calling an expert to service your aircon.

Refrigerant leak

If your air conditioner smells like a car’s exhaust, then this often indicates a refrigerant leak. Remember that your air conditioner does not work with a combustion engine, although this particular odour may be a result of the mix of fluids and heat.

In this case, it is important to stop using the air conditioner unit and call an expert as soon as possible as it can be dangerous. A refrigerant leak means that your air conditioner will not perform properly, which can result in further damage to key (and expensive) components like the AC compressor.

Furthermore, this scenario means chemical compounds are being released into the air. This refrigerant gas in the air that can affect yourself, your family, and the environment.

Also, while you wait for the expert to arrive, open the windows of your house and keep your home ventilated. This will help reduce the damaging effect of the chemicals.

Stuck animals

If your air conditioner is smelling like a rotten egg, this may mean that a rodent or any other animal has become stuck in the air conditioning system somewhere. This unfortunate event is not immediately dangerous to the health of your family.  However, it is important to solve the issue as soon as possible to avoid discomfort and more serious concern.

The best you can do if this is your case is find the exact location and extract the animal, as long as it is safe to do so. Clean the area and make sure you leave it dry so the odour doesn’t spread anymore or allow mould to form.

For future occasions, it is better to prevent this from happening by pest-proofing your aircon and home in general. For advise on how to prevent unwanted animal intruders, it may be best to contact an expert to discuss options.

Dirty air filters

If your air conditioner smells musky, mouldy, or like vinegar then this could be due to dirty air filters. On the other hand, if it smells like humidity/moisture, then the main cause may be water accumulating in the drain pan or ducts causing fungus to grow.

If you are suffering from water leaking you will also see it as water dripping down your wall, through the unit. This causes all sorts of property and electrical damage, and should not be left.

In any of these cases apply to you, it is better for you to call an expert so they can clean everything from the source outwards and manage the leakage as needed. Remember that regular air conditioner maintenance is important to avoid this kind of problem.

Burned air conditioner components

There are many electrical components in your home air conditioner.  If your aircon is expelling a burnt odour, this is likely because any of these components may be burning on the inside. For example, this could be due to a dead short and/or motor burn out.

If this is your case, then turn off your aircon immediately and call an expert to review the air con units. Do not try to fix it by yourself because it can be very dangerous.

Alternatively, if you haven’t used your air conditioner in a long time, the burning smell from the aircon unit could be due to dust burning a little bit on the inside. This is not necessarily dangerous. However, if the odour persistent then best to turn it off and call an expert.

Air conditioning odor at home

Cigarettes smoke smell

If your air conditioner smells like cigarettes smoke then this might be due to smoking in your house from you or your family. What you can do, without the help of an expert, is thoroughly wash the air filters more regularly and replace when needed.

Also, to avoid this strong odour that may cause allergies and headaches, obviously try to smoke outside. If looking to quit, don’t hesitate to reach out for help quitting once and for all.

Aircon smell immediate solution

If you have read the article so far and what we recommend for your situation is safe for you to go ahead with, then you can move onto the following:

Check the filters

A common reason for the appearance of unpleasant odours is the presence of dirt accumulated in the filters. This is because they progressively grow odour-causing bacteria or mould as a result.

Regular cleaning of the filters, in addition to preventing unpleasant odour, will help reduce the need for aircon repairs and reduce energy consumption. Such a simple step to save so much discomfort, breakdowns, and money!

In general, the filters should be checked and cleaned once every two weeks in winter and once a week in summer. Simply remove them, wash them with hot water and mild soap, and replace them once dry.

Woman checking the air conditioner

Clean the outdoor condenser

Generally, the outdoor unit of the equipment does not usually have a filter, so all the dirt from the street is deposited in the heat exchange coil in the AC condenser. Unfortunately, this dirt reduces the efficiency and thermal power, and cause more serious issues.

The unit and coil can be lightly brushed with a soft brush, or air used to blow off any matter built up.  However, more intensive cleaning or hard brushing is best left for the professionals. If not done properly, this can cause refrigerant leaks and/or electrical failure.

Check/clean condensate tray

The water condensate tray is responsible for a large proportion of unpleasant odours in air conditioning equipment. The smell can come from the water or matter growing in it.

We recommend that you clean the tray, at least once a year, with a disinfectant solution and check that the evacuation system is not clogged. This can be done carefully or left for a professional to do on annual-level service.

The drain

The drain of the indoor unit, which channels away water from condensation, is also the cause of many unpleasant odours in the aircon environment. If it is connected to the general drain of a building, these odours may come from there.

To solve this, it may be enough to place a siphon in the tube before connecting it to the general drain of the house. Otherwise, more serious intervention may be required.

Remember that if your air conditioning situation is presenting a risk to you, please call an expert to solve the problem. Trying to solve it by yourself when not appropriate is a common aircon mistake you should avoid as it can carry consequences from mild to major.

We hope you found this information useful. If you have any questions please feel free to contact us. We are always happy to help!