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How Many Amps Does a 1500 Watt Heater Draw? (Answered)

Written by Edwin Jones / Fact checked by Andrew Wright

how many amps does a 1500 watt heater draw

Space heaters are handy devices during chilly days. They can simply be plugged into an outlet to generate comforting heat without the need to chop wood or burn gas. However, an electric heater consumes a lot of electricity and may easily trip the breaker if its circuit is unplanned.

We can calculate how many amps does a 1500 watt heater draw to prevent such an issue. Generally, this device needs 12.5 amps at 120 volts or 6.25 amps at 240 volts.

Space Heater Amperage


The current draw of a space heater can be determined using the definition of power. Electrical power is defined as:

Power (watts) = Voltage (volts) × Current (amps)

We can manipulate the equation to get the space heater amps using:

Current (amps) = Power (watts) / Voltage (volts)

Thus, the current draw of a 1500 space heater when plugged in a 120 volt outlet is:

Current (amps) = Power (watts) / Voltage (volts)

= 1500 watts / 120 volts = 12.5 amps

This is true for any space heater rated at 1500 watts, whether it is a ceramic heater, an infrared heater, a fan heater, or a block heater for a vehicle.

Note that a 15 amp circuit at home is not exactly rated to be used at its maximum capacity of 1,800W.

The US National Electric Code, or NEC, limits the use of branch circuits to 80% capacity for continuous loads, so 1440 watt is the practical rating of a 15 amp circuit. It’s safer to put the appliance on a 20A circuit instead.

Meanwhile, a low amp space heater like a 750 watt heater and a 1300 watt heater may be used with a 15 amp circuit (see table below). Of course, a 2000 watt heater or a 5000 watt heater will definitely trip a 15 amp circuit breaker, so these usually come as a 220 volt space heater.

A 1500 watt 240 volt heater will have a current draw of:

Current (amps) =  Power (watts) / Voltage (volts)

= 1500 watts / 240 volts = 6.25 amps

The best way to choose the right heater that won’t trip breaker (or prevent space heater from blowing fuse if you live in older homes that use fuses instead of circuit breakers) is to check the current draw of the appliance. If a 1500 watt heater is too much, space heaters with other power ratings may be available.

Besides, here is a tool that allows for a swift calculation of amperage.

Here is a chart of how many amps does a space heater use with different power ratings and space heater voltage based on our equation. We did the solving for you, so you can simply check if the space heater you want is fine with the circuits in the room. A heater amps calculator is also available online:

Power of space heater (watts) Current draw (amps)
at 120 volts at 240 volts
100 0.83 0.42
200 1.67 0.83
300 2.50 1.25
400 3.33 1.67
500 4.17 2.08
600 5.00 2.50
700 5.83 2.92
800 6.67 3.33
900 7.50 3.75
1000 8.33 4.17
1100 9.17 4.58
1200 10.00 5.00
1300 10.83 5.42
1400 11.67 5.83
1500 12.50 6.25
1750 14.58 7.29
2000 16.67 8.33
3000 25.00 12.50
4000 33.33 16.67
5000 41.67 20.83
6000 50.00 25.00
7000 58.33 29.17
8000 66.67 33.33
9000 75.00 37.50
10000 83.33 41.67

Frequently Asked Questions


What size breaker for a 1500 watt heater?

Sometimes, a 1500 watt heater may be on a 15 amp circuit. However, it’s best to go for a larger size breaker, a 20 amp one, considering the 80% rule.

To learn more details about this topic, check it out here!

How many 1500 watt heaters on one circuit?

One 1500 watt heater can fit a 120 volt 20 amp circuit, since 80% of 20 x 120 equals 1920W. With this setup, you may still have room for some lights.

How many volts will I need for a 1500 watt heater?

A 1500 watt heater may come in either 120 volt or 240 volt variants. Choose the right variant for the available connection.


Space heaters will need a lot of electricity to work properly. They usually reach the maximum current capacity of a 15 amp circuit, so it’s best to place the device on a circuit with a higher rating.

After knowing how many amps does a 1500 watt heater draw, the frequency of circuit breaker trips can be reduced. These heaters can then continue to warm up the home without any interruption.

Read more in the following guide to calculate the exact amp for your appliances:

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