We recommend for this lamp to always be ON for 2 main reasons:
1) It will be more effective in killing germs, viruses and especially mold if kept turned ON 24x7.
2) The bulb is proven to last longer if kept ON all the time, as compared to turning it ON and OFF if connected to the fan.
So, for the installation, if you ordered the 24VAC lamp, you should get a 120v/240v to 24VAC transformer (not included with our lamp) and connect the 24VAC ballast (included with our lamp) directly to the power source. If you have the 120VAC ballast, then just need to connect it to a 120V power source.