Can our new system give us Legionnaire’s disease?

Advice for installers

If you’re an air conditioning installer or mechanic, you won’t be surprised at how often air conditioning installers are asked by customers if their new equipment puts them at risk of catching Legionnaire’s disease.

You know the answer to this question is ‘of course not’. But a bit of background information might also come in handy, so here’s some reassuring information to give to customers when they ask you about the disease and all that they may have heard about its supposed links to air conditioning.

Legionnaire’s disease – NOT directly from air conditioning systems

The first point to make is to do with how people actually contract Legionnaire’s disease. This is through inhaling Legionella bacteria held in airbound droplets of contaminated water.

Air conditioners don’t actually have any water in their systems so they can’t actually produce any of these bacteria. The only thing air conditioning systems could do is spread bacteria around a building.

So where does the disease originate?

The Legionella bacteria thrive in conditions where water is recirculated and kept in temperatures between 25° C – and 45° C – often in cooling towers, spas and humidifiers, and usually in older systems that have not been properly maintained.

Having said all this, it’s also important to point out that the disease is actually quite rare, and the risks are fairly minimal, which is why there is always such a lot of publicity when there is an outbreak.

Preventing Legionnaire’s disease

When customers ask you what they can do to minimise the risk of Legionnaire’s disease, point out that any water systems must be regularly cleaned to prevent any kind of organic growth, such as mould.  If water is stored between 25° C – and 45° C it’s a good idea to increase the temperature fairly regularly, for short periods, over 60OC.

The fact that there isn’t a connection between air conditioning systems and contracting Legionnaire’s disease doesn’t stop the myth from spreading, so hopefully the information here will help you to explain things to customers who might be worried or concerned about it…..

(Some very large air conditioning systems have water cooled outdoor units which utilize cooling towers, which may be the source of Legionella bacterium of not properly maintained.)

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