1000 watts is a lot of electricity.
An appliance or electrical device that uses 1000 watts would consume 1 KWH in 1 hour of run time.
If your cost of KWH is 10 cents per KWH then that 1000 watts would cost you 10 cents per hour.
A 1500 watt heater can heat around 150 square feet room.
If your room is bigger than 150 square feet then you need 2 1500 watt heaters.
1500 watts does use a lot of electricity.
A 1500 watt appliance such as a 1500 watt heater uses around $1.20 to $1.50 per 8 hours of run time.
In 24 hours a 1500 watt heater or appliance can use as much as 36,000 watts of electricity and at 10 cents per KWH that would equal $3.60 per 24 hours of run time.
A 1500 watt heater running for 8 hours will cost $1.20 for 8 hours of run time at 10 cents per KWH.
If your KWH is more then it may cost you $1.40 to $1.80 per hour depending on the cost of your KWH in your area which can vary.
A 1500 watt heater will use 1500 watts per hour of run time so that means in 8 hours the 1500 watt heater will use 12000 watts in the 8 hours.
In 1500 Watts there are 12.5 amps at 120 volts.
If you have an appliance that is drawing 1500 watts at 120 volts then the 1500 watt appliance is drawing 12.5 amps.
For example if you have a 1500 watt space heater then your 1500 watt space heater will draw up to 12.5 amps so you need to make sure you have enough amperage capacity to supply the 1500 watt heater or appliance.
A 1500 watt appliance or electrical device should be on a dedicated circuit or at least on a circuit without anything else.
Remember the equation watts = volts*amps. If you have a 1,500W heater at 120V, it is using 12.5amps (1,500/120=12.5).
Alternatively, if you have a 1,500W heater at 240V, it is using 6.25amps (1,500/240=6.25).
A 1500 watt space heater (on high setting) will draw 12.5 Amps.
When a few lights or a television are on the same circuit, the 15 Amp limit is quickly reached and the breaker will trip.
A 1500-watt heater on a 120-volt circuit thus needs a breaker of 15.6 amps.
Because a 15-amp breaker would be too small, you need a breaker with the next highest rating, which is 20 amps.
A 1500 watt heater uses exactly this, 1500 watts per hour, relative to 24 hours, heating a modest-sized room.
Many household products use just as much if not more than 1500 watts, so, relatively speaking, heaters are fairly reasonable in terms of energy required.