I want to replace a standard bathroom exhaust fan with a exhaust fan/heater combo. I live in the Chicago suburbs and it can be pretty cold in the bathroom in the morning.

My home has the electrical wires running through conduit which I understand is local code.

I want to wire the fan/heater in such a way that there is a switch for the fan and one for the heater. During the summer, I'll want to run the fan but not the heater.

Can I just run an extra hot and neutral wire through the existing conduit to add another switch?

Thanks for your help!

The questions are:
1. Can the circuit handle it. Most likely yes, the heater+light rarely exceeds 1200 Watts. Of course, you'll have to decide what else is on that circuit (not really so much a code factor than a nuisance factor). If it's on the same circuit as the receptacles in the bathroom, anybody with teenager daughters knows that one of those monster blow driers can trip a circuit.

2. Can you shoehorn the unit you want into the space your existing fan is in and get the exhaust duct to line up.