01 Sep 2022

How to Avoid Smells in Your Air Conditioner

Avoid unpleasant odours and unhealthy conditions with our essential maintenance tips for your air conditioner.

When it is too hot or cold outside, there is nothing better than stepping into the comfort of your home, especially when the air conditioning awaits you. But there is one thing that can spoil the moment: an unpleasant odour coming out of the air conditioning unit. Bad smells can indicate that something is “off” with your air conditioner. However, it is a fairly common issue, and, depending on what’s causing the smell, it can be easy to eliminate and, even better, prevent.


The air we breathe impacts our health, and our home’s environment should be kept as healthy as possible. When there are bad odours circulating indoors, it lowers our home’s indoor air quality (IAQ). Learn more about the impact of IAQ on our health and how it can be improved. Air conditioning not only provides the right temperature, but it can also improve IAQ through specialized filters and help to reduce humidity. However, if the unwanted smells originate from your air conditioner, don’t ignore them for too long and find the cause behind them, not only for your comfort but also for the health of your AC.



What causes smells in your air conditioner? 


There can be different reasons why your air conditioner has developed unpleasant smells, but some of the most common types of smells are a musty or mouldy one that is often caused by three issues:

  1. Air filters need cleaning or replacing. If it has been a while since the last time your air conditioning filters were cleaned, it is possible that the dirt trapped is causing a musty smell. AC filters are a barrier against dust, hair and allergens, they work to trap these particles, and over time the build-up in the filters can affect airflow, preventing moisture from fully escaping, and leading to the growth of bacteria, leading to smells.

  2. Mould or mildew. Speaking of moisture, an excess amount of it can cause a greater issue, which is the growth of mildew and mould. These can lower the IAQ of your home, and you may notice an increase of allergic reactions, such as sneezing and throat irritation, and other respiratory issues among your family members.

  3. Clogged or poor drainage. The water droplets that can collect inside air conditioners normally get disposed of through the AC’s drain pipe. If an expectation of the drainage system becomes clogged or not working properly, condensation can build up and cause a stagnant water smell, as well as leading to the aforementioned issues. Water puddling in the unit can also cause electrical damage, another reason to solve this issue as soon as possible.


Getting Rid of Bad Odours


Getting rid of odour from your air conditioner


Eliminating undesired smells from your AC unit does not have to be a complicated process, but always make sure to keep these recommendations in mind before doing anything: Remember to turn the AC power supply off before performing any cleaning or maintenance tasks. Additionally, follow the instructions found in your appliance’s user manual to check for any other hazards and safety guidelines. Once you are ready, here is what you can do:


  • Perform filter cleaning.
    Filter maintenance is not only key for avoiding any smells, but also for maintaining optimum IAQ and ensuring the AC’s energy consumption is consistent and efficient. The reason AC filters become smelly is that when dirt gets trapped on them, it can cause spores to grow and the odour gets trapped or passed on to the air. Dirt builds up in the filters also restricting airflow, and trapping more moisture in. The resulting musty smell can stay around and become more noticeable when you turn the AC on. If this seems to be the case, it’s time to get those filters cleaned or replaced.

    Filter cleaning can be easily performed by you on wall-mounted split air conditioners by removing the front panel, and locating the air filters, which can be gently pulled out. Washing the air filters in warm water should be enough to get the dust and particles off. It is not recommended to use any detergents, as they can deteriorate the filter. Let them air dry in a shaded place, to prevent any damage from sunlight, and check that they are dirt and moisture free before putting them back in the unit. Read our article for an in-depth step-by-step guide on filter maintenance and cleaning.


  • Check the condensation drain pan.
    When you remove the air filters from the AC unit, you will find the condensate pan or drip pan below the evaporator coils. This pan collects any water droplets from the condensation that forms in the unit and is carried out through the drainpipe. Finding water on the pan is normal, but if there is dirt, it can become an issue if it starts preventing the water from draining. Dirt and water can build up, creating lumps of slimy debris that stick to the components and impede condensation from flushing away. This build-up can also decrease the unit’s efficiency and power, and may even cause obstruction in the system.

    To eliminate dirt, clean the pan with a soft cloth, you may apply a mild detergent to get rid of odour-causing bacteria. Then, check that the pan drains well by pouring a small amount of water over it; it should easily flow out through the drain line.


  • Check the drain line.
    In some cases,
    even if the AC condensation pan is clean and properly maintained, moisture may not drain correctly. The next place to check for clogging is the drain line, which is the pipe that conducts condensation to the outside. When this occurs, the best plan of action is to contact your local air conditioning specialist to unclog the drain line. Using home methods without expert knowledge, such as chemical drain cleaners, can deteriorate the pipe, as some chemicals are too corrosive. To safely get rid of clogging, the technician may use a process of mechanical suction to clean the pipe without damaging it.


We have gone over some of the most common reasons an air conditioner may produce undesired smells, and how to clear up those issues. However, it is possible that your air conditioner has another issue, and the methods above did not work, or you prefer to rely on an expert to perform the cleaning. If that is the case, as mentioned before, contact the Hitachi National Service Centre to arrange for a technician to inspect your unit.


Other types of smells, such as burning or a gas-like scent, may need prompt professional intervention. The reasons for such odours in your air conditioner may range from gas and refrigerant leakage to overheating and even electric malfunctioning. When you suspect the smell in your AC is not due to moisture or clogging, again, the guidance of an expert can help prevent further damage to your air conditioning system.


Preventing Bad Smells in Your Air Conditioner


How to prevent bad smells in your air conditioner


We’ve talked about how to get rid of the causes, but an even better and more effective way to keep these smells away is through prevention. A regularly maintained and clean air conditioning system will stay efficient and effective for longer, providing cooling and comfort for many years to come; so, the best plan of action is to have a schedule for those maintenance tasks. Here are some tips to stay on top of the AC maintenance routine:


  • Clean the AC filters right before the change of season. Making sure the filters are in optimal condition before summer or winter starts will prevent dirt from building up, and you will benefit from fresher air and better IAQ. This is also a great way to reduce allergic flare-ups right before hay fever season begins.

  • Schedule a yearly maintenance checkup. Set a day in advance to have an authorised technician look at your air conditioning system. Let them know of any past repairs or new changes you may have noticed about your AC. They may check for leakage, excess humidity, or any other concerns. This way you will be ahead of any moisture build-up issues before they even have a chance to bother you.

  • Deep clean your air conditioner units once a year. Use a vacuum cleaner to safely remove any dust or debris from both the indoor and outdoor units. This should be enough once a year, as you may continue to do more superficial cleaning on a daily basis, by wiping off any dust from the outer casing. Your AC system will thank you while running more smoothly throughout the year.



Easier cleaning with Hitachi Residential Air Conditioning


Innovative technology is developed to make our lives easier. Which is exactly what ranges like P-Series and the smart maintenance features are meant for. These self-maintenance functions help your AC system work in optimal condition for longer, without you having to worry too much about cleaning.


  • FrostWash™. This technology is a self-cleaning feature that freezes moisture inside the indoor unit, trapping dust and particles in the ice, and then melts it and washes it away, keeping the interior clean without you needing to do anything. Through this feature, it is possible to enjoy up to three times better airflow than similar systems that don’t use FrostWash™.

  • Mold guard. Another odour-busting feature is the built-in mould guard that prevents bacteria and mildew from growing. After each use, the mould guard function gently blows air through the internal components to remove any remaining dampness. Without a moist environment, mould and other bacteria cannot survive, making your air conditioner experience healthier and more comfortable.


ꟷ Hitachi Cooling & Heating Australia ꟷ
01 Sep 2022