Without knowing more about the wireing in the home it is difficult to answer.
However, somthing that might help is
Voltage X amps = Watts
So, Amps = Watts / Voltage
1800 watts/120 volts =15 amps. Normal household circuits will be 15 amps.
You would be pulling 100% of the circuits rated capacity if it is a 15 amp breaker with just the heater alone.
Next you can look at the gauge of the wire. If it is 14 gauge then 15 amp is the max amp allowed.
12 Gauge could carry a 20 amp circuit.
I know this does not exactly answer your question but might help