Clean air conditioning in schools and childcare: why it matters.

Research into asthma, allergies and building health points to a simple conclusion for school and centre leaders: what is growing inside an air conditioner matters, and regular professional cleaning is one of the most practical ways to look after the air in a classroom.

Classrooms are where children spend their days

Apart from home, school is the indoor environment where children spend most of their time.^[1] That makes the air inside classrooms, and the equipment that conditions it, an important part of a child’s daily environment.

Asthma and allergies are common, and indoor triggers matter

Asthma Australia figures report that one in nine Australians has asthma, about 2.7 million people.^[2] For children with asthma and allergies, the indoor environment is a big part of the picture.

The Australian Asthma Handbook identifies house dust mite as a major asthma trigger in Australia, noting that dust mites thrive in temperate, humid climates such as coastal Australia. It also notes that airborne mould particles can act as both irritants and allergens.^[3] A New South Wales study of childhood asthma found that sensitisation to house dust mite was the most important risk factor for current asthma, and that children with large reactions were most at risk of severe illness, including disturbed sleep, days missed from school and urgent medical attention.^[4]

Mould tends to grow where moisture is not controlled, and exposure can trigger asthma in some people.^[2] That is relevant to air conditioners, because parts of the system are designed to stay damp.

What builds up inside an air conditioner

The cooling coils and drip pans inside an air conditioner are designed to stay moist, which makes them supportive environments for the growth of undesirable microorganisms.^[5]

Research on split system units backs this up. In a 2023 study published in Indoor Air, researchers took apart ductless mini-split units in 17 Japanese homes and sampled their internal parts. They found high levels of fungal DNA in all interior parts, with the blower fans the most contaminated. The parts downstream of the heat exchanger were the main sites of fungal contamination, which may pollute the indoor air. High-pressure washing reduced fungal abundance by more than 99% in every part of the unit.^[6]

Another study sampled the air in 122 shops with split air conditioning systems. Before the units were switched on, potentially pathogenic and pathogenic bacteria were found in 6.4% of air samples and mould in 27.8%. After 30 minutes of operation, bacteria were found in 97.5% of samples and mould in 72.1%. The microorganisms found in the air matched those in the biofilm in the unit’s condensate drainage system.^[7]

What research links to uncleaned coils and drip pans

Studies of office buildings have linked the condition and cleaning of air conditioning components to how occupants feel.

• In the US EPA’s BASE study of 100 office buildings, researchers found increased occupant symptoms associated with a lack of scheduled cleaning of air conditioning drain pans and cooling coils, and with poor condition of cooling coils.^[8] Dirty cooling coils were identified as a risk factor for lower respiratory symptoms.^[9]
• A further analysis of that data found almost triple the rate of weekly building-related lower respiratory symptoms in buildings where the drip pans under cooling coils were not cleaned. Lack of cleaning of either drip pans or cooling coils was also linked to more mucous membrane symptoms.^[10]
• An earlier study of 80 office buildings linked lower respiratory symptoms to moisture and contamination factors in HVAC systems, such as poor drainage under cooling coils. The associations tended to be stronger among people with physician-diagnosed asthma.^[11]
• A blinded, controlled trial in office buildings tested ultraviolet irradiation of cooling coils and drain pans, the parts of an air conditioner where microbes grow. Occupants reported substantially fewer symptoms when the ultraviolet treatment was switched on.^[5]

What a proper clean actually involves

A quick wipe of the filters is not enough. Breezehouse technicians work deep inside the system, using premium products and treatment methods.

What this means for schools and centres

A regular professional clean of your split system or ducted air conditioning is a practical way to:

• Remove the dust, moisture and microbial build-up that collects on coils, drain pans and blower fans
• Reduce a source of mould and allergens in rooms where children with asthma and allergies spend their day
• Keep the system running as intended through long school terms and humid summers
• Show families and staff that you take the classroom environment seriously

Book your school or centre in

Breezehouse cleans split system and ducted air conditioning. Call us on 0485 016 740 to book your school or childcare centre in, or send an enquiry below.

Learn more about split system air conditioning servicing and ducted air conditioner cleaning.