Air conditioning manufacturers frequently make claims about air quality improvement. Some of these claims are well-founded; others are marketing rather than substance. Here is an honest assessment of what air conditioning actually does to the air in your home or office.
What Air Conditioning Definitely Does
Filters particles: All air conditioning indoor units have an air filter that captures dust, pollen, pet dander and other particles above a certain size as air passes through the unit. Standard filters capture particles above approximately 10 microns. The filter needs regular cleaning to remain effective — a blocked filter bypasses this function entirely.
Reduces humidity: When an air conditioning system cools air below its dew point (the temperature at which moisture condenses), water precipitates out of the air and collects in the condensate drain. This dehumidification effect reduces indoor humidity, which inhibits mould growth and can reduce the house dust mite population (which thrives in humid conditions). For allergy sufferers, reduced humidity can be meaningful.
Enables windows to remain closed: Running air conditioning with windows closed reduces the ingress of outdoor pollutants, pollen and traffic emissions. For urban properties near busy roads, or for hay fever sufferers during high pollen periods, this is a genuine air quality benefit.
What Premium Systems Add
HEPA-equivalent filters: Some premium units include higher-grade filters that capture smaller particles — including some bacteria and virus particles. Mitsubishi Electric’s Plasma Quad and Daikin’s Flash Streamer technology both claim evidence for pathogen reduction. The evidence base for these technologies is generally credible, though real-world impact depends on filter maintenance.
Ionisation and photocatalytic oxidation: Several manufacturers include ionisation or photocatalytic technologies that generate reactive oxygen species (hydroxyl radicals, hydrogen peroxide) that can break down volatile organic compounds (VOCs) and inhibit biological pathogens. The evidence for meaningful benefit in normal room conditions (with relatively large air volumes and limited dwell time in the unit) is more mixed than manufacturer marketing suggests.
Carbon filter layers: Some premium units include activated carbon filter layers that adsorb VOCs, cooking odours and similar gaseous pollutants. These are effective but the carbon filter has a limited lifespan and requires periodic replacement rather than just cleaning.
What Air Conditioning Does Not Do
Air conditioning does not ventilate — it recirculates the same air rather than bringing in fresh air from outside. In a well-sealed modern home, this means CO2 levels can increase over time without adequate ventilation. Air conditioning for air quality should be considered alongside adequate fresh air ventilation — not as a replacement for it.
Call 07833 053749 or contact us if you have air quality specific requirements.