Hi Annette, it's Jack at Dyson.
When you lower your AM05's target temperature (shown on the LED display on the front of the machine) down to 0°, the red light around the on/off switch will turn blue. This shows your machine is now running in fan-only mode, without the heating elements - suitable for use in hot weather. You can then adjust the airflow power and oscillation to suit your needs.
I hope this helps. If you need any further advice, visit www.dyson.com and click 'Support'. Or if you'd like to speak directly with our experts, you can reach the Dyson Helpline on 1-866-693-9766 (US), 1-877-397-6622 (CA) 1800 239 766 (AU), or 0800 298 0298 (UK).