4000-watt Electric Heater | 7 Answers You Should Know

Wondering whether the 4,000-watt heater is the right space for your garage, living room, or any other space that you need to heat?

Are you unsure about the installation specifics – breaker, wire size to use for being code compliant? Do you want to know how you can safely maintain your electric heater?

So, in this post, I have compiled :

  • 7 key answers to commonly asked sizing, wiring details,
  • what space size it is suited to heat, how to maintain it,

and indicative costs of running the heater to help you decide whether a 4,000-watt heater is a right fit for your heating needs and the wiring information to help you connect it safely.

#1. What Size of Breaker for a 4000-Watt Heater?

A 4,000 watt, 240/220V heater should be connected to a 30A circuit breaker. Make sure to use a dedicated breaker for this heater!

A 20A circuit breaker could work as well but may not be NEC code compliant.

Circuit breakers for continuous loads such as space heaters should be rated 125% of the rated current load.

The rated current for a 4,000 watt, 240 V heater is 4,000/240=16.7A.

16.7 A x 125% = 20.83A which requires a 25A or 30A breaker – the next standard size.

Make sure to consult the heater user manual for the recommended circuit breaker rating for use with the heater.

#2. What Wire gauge for 4,000 watt heater?

You should use a 10/2 with the ground, 10AWG wire for your 4,000-watt, 240V heater or higher.

The 10 AWG wire is rated at 30 amps.

Confirm that the electric heater is plugged into a 220/240V outlet.

But nonetheless, consult the user manual for the specific heater, some user manuals for 4000 watt/240V heater recommend the use of 12/2 or 12/3 wire gauge, and some users have reported using it without any issues.

It is important that it is a dedicated circuit and that there are no other heavy appliances connected to it to minimize the risk of overloading the circuit.

#3. How many Amps Does a 4000-Watt Electric Heater Draw?

A 4,000-watt heater draws at 240V draws between 16 – 17 amps when running. The time the heater runs depends on two factors:

  • how quickly it takes the heater to attain the set temperature and
  • for how long the attained temperature can be maintained in the room.

The heaters have a thermostat to automatically switch them off when the desired temperature is attained.

The larger room a room is, the longer the heater takes drawing the rated current.

Also if a room loses heat quickly, if for instance it is poorly insulated, the heater has to work for a longer duration to maintain the desired temperature.

#4. How many sq. ft a 4,000 watt Space Heater is suited to?

4000-watt heaters are generally suited to heating spaces of about 400-600 sq. ft.

Beyond that, there are factors that determine how well-suited a heater is for a certain space.

Factors include the design of the heater – does it have a fan or not as an example, whether the space to heat is insulated or not, the number of windows, and the general climate of your area.

In general, insulated spaces, spaces with few windows, and locations with warmer climates need less heating.

Also, note the danger in using this heater for a much larger room, the energy draw will be higher because the heater will be running continuously to try and warm up the large area.

#5. How Much Electricity (kWh) Does a 4,000 watt Heater Use?

A 4,000-watt heater consumes approximately 4,000 watts of electricity.

The actual energy used (kWh) depends on the heater’s usage pattern. In some cases, the heater is only switched on for a few hours when needed.

This may be the case if you occasionally need heating in the garage as an example. During its use, the heater cycles on and off to maintain the set temperature.

So it is difficult to estimate the actual energy use.

What Is the Cost per Hour of Running a 4,000-Watt Heater?

To obtain the cost per hour, multiply the heater’s energy consumption (kWh) x the electricity tariffs for your location.

For example, taking an electricity tariff of $0.133 and a 1333kWh – assuming the heater is only on for 1/3 of an hour,

the cost of running the heater = $0.133 x 1333kWh =$177 at full power!

What Is the monthly cost of Running a 4,000-Watt Heater?

To obtain the monthly energy usage, multiply the heater’s energy consumption over a month (kWh) x the electricity tariffs for your location.

How much does it cost to run a 4,000-watt heater for 24 hours?

To obtain the 24-hour energy usage, multiply the heater’s energy consumption over 24 hours (kWh) x the electricity tariffs for your location.

#6. How many BTU is a 4000-watt heater?

A 4,000-watt heater is about 13,760 BTU.

This can be calculated using the ratio, 1 W = 3.41 BTU/hr. 4,000 watts is 4000 x 3.41 = 13,760 BTU/hr.

#7. How Do You Maintain the Electric Heater Safely?

Simple Maintenance of electric heaters involves wiping off the dust from the heater vents periodically. There are important safety guidelines to be aware of:

  1. Switch off the electric heaters first and allow them to cool.
  2. Wipe with a damp cloth any dust builld up on the vents and wipe the vents dry.
  3. Only reconnect the heater to the grid after it has dried properly to prevent electric shocks!

In summary,

A 4000-watt space heater rated 240V draws approximately 16.7 amps when running.

It has a heating capacity of 13,760 BTU/hr and it should be connected to a 10 AWG wire and protected with a 30A circuit breaker.

Note though that some manufacturers recommend the use of 12 AWG wire with the 4000-watt heaters.

In general, this size of heating capacity is suited to heating rooms of 400-600 sq. ft.

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