Sam Takoy wrote in -
september.org:

Hi,

Looking for a cheap but reliable solution.

I want a fan to turn on when my thermostat is on. Is there a gizmo that
would do that for me. My fan is line voltage.

Many thanks in advance,

Sam

I have a line voltage, 120 volts, thermostat in my poolroom. It is for
heating only. Thermostat turns on a fan. Airflow thru an inline heater
causes heat to come on only when fan is running. Anyway, what you need is
called a line voltage thermostat. They are common and cheap.