Calculate total circuit load and check capacity.
The NEC (National Electrical Code) requires that continuous loads not exceed 80% of a circuit's rated capacity. A 20A/120V circuit has a maximum capacity of 2,400W, so continuous loads should not exceed 1,920W.
Always consult a licensed electrician for any work on your home's electrical system. Improperly wired circuits are a leading cause of house fires. Permits are required for most electrical work in occupied dwellings.