From the wording of your question it sounds like you are already operating both fans simultaneously from one switch. The switch that comes with the fan is rated for 1.2 AMPS. Each fan draws 0.67 AMPS, so using one of the included switches for both fans is slightly over working the included switch. Emerson makes a rotary control model SW93 (see below) that is rated for up to 3 amps, which would be a better choice. You can find our contact info here if you wish to order the switch or discuss further options.

SW93 Rotary Control:

Thank you very much for your reply. This is super helpful.