Is this household device linked to Legionnaires’ disease?

QUESTION: Hey Dr Zac, over winter I was cranking up the heater, but someone at work mentioned these reverse cycle heaters/air conditioners, especially older ones, can spread bacteria like legionella . We also have a gas heater in the kitchen, and he said that can emit carbon monoxide. Is that true? With summer coming up – should I stop using our reverse cycle airconditioning . What should I use instead!? Melbourne can get putrid during the hot months. What’s the safest way to stay warm and cool without risking my health? – Carla, 42, Dandenong VIC

ANSWER: Dear Carla, thanks for your question. Melbourne’s four-seasons-in-a-day climate means our heaters and airconditioners work overtime but do they put our health at risk? Let’s clear it up. 4

Air-conditioners and legionella