A 15 amp electrical circuit can handle up to 1800 watts at 120 volts before the breaker will trip to prevent the wire from overheating.
On a 20 AMP circuit the electrical circuit can handle up to 2400 watts at 120 volts before the breaker trips.
Although it's best to keep the wattage under 1800 watts for a 15 amp circuit and under 2400 watts for a 20 AMP circuit.
So I would put no more than 1700 watts of electrical load on a 15 amp circuit and no more than 2300 watts on a 20 amp circuit to keep your home safe and prevent overloading of the circuits all the time and causing your breaker to trip.