A split air conditioner that is not cleaned or disinfected ends up becoming a breeding ground for bacteria, fungi and bad odours that spread throughout the room. What is more, with a dirty coil and filters the unit cools less effectively, uses more energy and breaks down sooner.
In this guide we explain how to clean a split air conditioner step by step and how to disinfect it afterwards, which product to use on each part of the unit and how often to do it. It is the same process that installers follow with our range of air conditioning cleaners.
The importance of air-conditioning maintenance
Regular maintenance of air conditioning prevents the proliferation of microorganisms in the filters, the evaporator and the ducts, which are the points where moisture and accumulated dust create the perfect conditions for the growth of bacteria and fungi. Without periodic cleaning, the unit recirculates that contaminated air throughout the room.
In addition to the impact on health, a dirty air-conditioning unit has to work harder to reach the desired temperature, which translates into higher electricity consumption and premature wear of components. Simple preventive maintenance avoids most breakdowns and costly repairs.
How to clean a split air conditioner step by step
Cleaning a split unit thoroughly is more than washing the filters: you also need to treat the coil (the evaporator), the condensate tray and the drain. You need a cleaner for the coil, such as AIRNET® SPRAY, and a bactericidal and fungicidal disinfectant, such as AIRPUR® SPRAY; both come together in the AIRNET & AIRPUR SPRAY kit.
1. Disconnect the unit and clean the filters
- Switch off and disconnect the unit from the electrical supply before handling it.
- Remove the filters carefully. On most split units, they are accessed by opening the front cover of the indoor unit.
- Shake off the coarse dust over the bin or vacuum the filters before wetting them.
- Wash them with warm water and mild soap. Rub gently with a soft-bristled brush. Avoid bending or deforming them.
- Rinse well and leave to dry completely before reinstalling them. A damp filter encourages mould growth.
- Refit the filters and reconnect the unit.
The filters should be cleaned every two to four weeks during the season of use. You will find the detailed process, including the most common mistakes, in our guide to cleaning air conditioner filters at home.
2. Clean the coil with AIRNET SPRAY
With the filters removed, switch the unit on. Spray AIRNET® SPRAY onto the front and top of the coil (the metal fins the air passes through), from 15–20 cm away and until saturated. Leave it to act for about 15 minutes: the dirt dissolves and runs out through the tray to the drain, with no need to scrub. Do not spray onto electrical or electronic parts.
If the coil has heavily encrusted grease or mineral deposits, AIR DISLIM is a technical cleaner for very dirty coils that is applied, left to act and rinsed off with plenty of water.
3. Check the tray and the drain
Check that the condensate tray and the drain pipe are not blocked: if the water does not flow, the dirt washed off by the cleaning stays in the tray and the bad odour returns. Clean the outside of the indoor unit with a damp cloth, without abrasive products.
How to disinfect the air conditioning
Disinfecting your air conditioning is a different step from simply cleaning it. Cleaning removes visible dirt; disinfection eliminates microorganisms (bacteria, fungi, viruses) that cannot be seen but that affect air quality and respiratory health.
To disinfect the air conditioner you need to use a bactericidal and fungicidal product formulated for air conditioning. In a domestic or office split unit, AIRPUR® SPRAY is applied after cleaning the coil with AIRNET® SPRAY; both come together in the AIRNET & AIRPUR SPRAY kit. For professional installations there is AIRPUR PRO, a bactericide, fungicide and virucide to be applied exclusively by specialist personnel.
To disinfect your air conditioning correctly:
- Clean the filters and the coil first: the disinfectant has to reach the surface, not the dirt.
- With the unit running, spray AIRPUR® SPRAY onto the front and top of the coil, from 15–20 cm away and until saturated.
- Leave the unit running so that the product spreads throughout the circuit.
- Put the filters back once they are dry.
- Repeat the disinfection at the beginning and end of each season of use, or whenever the bad odour returns.
If the split unit smells bad, AIRPUR® SPRAY acts on the cause, the fungi and bacteria on the coil, and leaves a light fragrance: that is why it works as an air freshener for air conditioners and does not simply mask the odour. In spaces with a lot of people coming and going, such as offices, shops or healthcare centres, it is advisable to disinfect more often.
How to clean the air conditioner outdoor unit
The outdoor unit (the condenser) is exposed to the elements and builds up dust, leaves, pollution and grease on its coil, which reduces heat exchange and makes the compressor work harder. It is cleaned with the unit switched off and disconnected.
- Remove leaves and coarse dirt from the grille with a soft brush.
- Spray a degreasing cleaner for condensers: AIR SERNET RTU comes ready to use; AIR SERNET is diluted 1:10 with water and AIR SERNET SUPER from 1:5 to 1:20, for the most encrusted dirt.
- Leave it to act for about 5 minutes and rinse with low-pressure water, from the inside out.
- Wait until the unit is dry before switching it on: these are water-based products.
- If the unit loses capacity, ask a technician to check the refrigerant gas: a low charge usually indicates a leak.
Products for cleaning and disinfecting air conditioning
Air Dislim, a technical cleaner for very dirty coils
AIR DISLIM is a technical cleaner based on fast-evaporating solvents for evaporator coils and air conditioning equipment with grease, sludge or mineral deposits. It is applied to the surface, left to act and rinsed off with plenty of water.
Airnet & Airpur Spray Kit: bactericide, fungicide and disinfectant
The Kit Airnet & Airpur Spray brings together the two steps in treating a split unit: AIRNET SPRAY cleans the filters and the coil, and AIRPUR SPRAY disinfects it (bactericidal and fungicidal) and eliminates the bad odour.
Airpur PRO, a bactericide, fungicide and virucide for professionals
AIRPUR PRO eliminates bacteria, fungi and viruses from air circuits and is the right disinfectant for installations with a lot of people coming and going or in the food industry. It is authorised by the Directorate-General for Public Health of the Spanish Ministry of Health and must be applied exclusively by specialist personnel.
Air Sernet: cleaning of condensers and coils
Air Sernet is formulated for the specific cleaning of condensers and coils. Its non-corrosive formula removes residues that reduce system efficiency without damaging the materials, extending the service life of the components.
Air Sernet Super: powerful cleaner for air-conditioning components
Air Sernet Super is the higher-strength version for the thorough cleaning of air-conditioning components. It is especially suited to industrial and commercial environments where dirt build-up is more intense and maintenance schedules are more demanding.
Tips for effective maintenance
- Schedule periodic inspections with a technician: beyond the maintenance you can carry out yourself, an annual professional inspection ensures that the refrigerant system, the electrical connections and the internal components are in perfect condition.
- Always use products specific to air conditioning: general-purpose cleaners may contain corrosive components that damage the evaporator fins or degrade the plastics of the unit. Products formulated for air conditioners are safe for all of their materials.
- Keep the area around the unit clean: the less dust and dirt there is in the room, the less the filters will get dirty. Ventilate regularly and avoid placing objects that collect dust near the units.
Conclusion
Cleaning and disinfecting your split unit regularly is the best way to have healthy indoor air and a unit that works well for years. With a cleaner for the coil, a bactericidal and fungicidal disinfectant and a degreaser for the outdoor unit, you have all the maintenance covered, without generic products that could damage the unit.
You will find all the products in our air conditioning cleaning category. And if you are looking for something more specific, the blog has guides on cleaning the filters at home, cleaning air conditioning ducts, professional cleaning with AIRNET PRO and AIRPUR PRO, the differences between Airpur and Airnet and bad odours in car air conditioning.
Frequently asked questions about how to clean and disinfect air conditioning
How often should air conditioning be cleaned?
Air-conditioning filters should be cleaned every two to four weeks during periods of intensive use. Complete disinfection of the evaporator and ducts is recommended at the beginning and end of each season, that is, before summer and before winter. The outdoor unit should be checked and cleaned at least once a year, preferably in spring.
Can air conditioning be cleaned with bleach or chlorine?
It is not recommended to clean air conditioning with bleach or chlorine. These products are corrosive and can damage the evaporator fins, plastics and metals of the unit, as well as generating toxic fumes on contact with residues in the system. To disinfect air conditioning correctly, use bactericidal and fungicidal products formulated specifically for air conditioning, such as Airpur or the Airnet & Airpur Spray Kit.
How do I know if my air conditioning has bacteria or fungi?
The most common signs that an air conditioner has bacteria or fungi are: a bad smell when the unit is switched on, dark or greenish stains visible on the filters or grilles, an increase in respiratory or allergic symptoms among the people who use the space, and a feeling of stale air even when the unit is running. If you detect any of these signs, carry out a complete cleaning and disinfection of the unit as soon as possible.
Which product is best for disinfecting air conditioning?
A bactericidal and fungicidal product formulated for air conditioning, applied after cleaning the coil. For a domestic or office split unit, AIRPUR® SPRAY; to clean and disinfect in two steps, the AIRNET & AIRPUR SPRAY kit. In professional installations, AIRPUR PRO, which is also virucidal and is applied by specialist personnel.
Can I clean the air conditioning myself or do I need a technician?
Cleaning the filters, disinfecting the evaporator and cleaning the outside of the indoor unit are tasks that any user can carry out without technical knowledge. What does require a certified technician is checking the refrigerant circuit, checking the internal electrical connections and cleaning the outdoor unit at height. As a general rule: anything that involves opening the unit beyond the filter cover or handling the refrigerant gas must be done by a professional.