Does a Space Heater Need a Dedicated Circuit?

Space heaters are a popular solution for supplemental heating, providing targeted warmth in specific areas of a home or office. However, the power requirements of these devices can pose a significant challenge to a building’s electrical system, making the question of whether a space heater needs a dedicated circuit a critical one.

Understanding the Power Demands of Space Heaters

Space heaters come in a variety of sizes and wattage ratings, with the most common ranging from 1,000 to 1,500 watts. These high-power devices can easily overload a standard household circuit, which is typically rated for 15 or 20 amps. A 1,500-watt space heater, for example, can draw up to 12.5 amps, leaving little room for other electrical loads on the same circuit.

Calculating the Electrical Load

To determine if a space heater requires a dedicated circuit, it’s essential to understand the concept of electrical load. The total electrical load on a circuit is the sum of all the devices and appliances connected to it. The National Electrical Code (NEC) recommends that the total load should not exceed 80% of the circuit’s capacity.

For a 15-amp circuit, the maximum recommended load is 12 amps (15 amps x 0.8 = 12 amps). For a 20-amp circuit, the maximum recommended load is 16 amps (20 amps x 0.8 = 16 amps). Exceeding these limits can lead to circuit overloads, tripped breakers, and even potential fire hazards.

Dedicated Circuits for Space Heaters

does a space heater need a dedicated circuit

The NEC has specific requirements for the use of dedicated circuits for certain high-power appliances, including space heaters. According to the code, space heaters with a rating of 1,500 watts or more should be installed on a dedicated 20-amp circuit.

Benefits of a Dedicated Circuit

Installing a dedicated circuit for a space heater offers several advantages:

  1. Prevent Circuit Overloads: A dedicated circuit ensures that the space heater is the only device drawing power from that circuit, reducing the risk of overloading the circuit and tripping the breaker.

  2. Ensure Consistent Power Delivery: With a dedicated circuit, the space heater will receive a consistent and uninterrupted power supply, preventing fluctuations or drops in voltage that could affect its performance.

  3. Enhance Safety: Dedicated circuits help mitigate the risk of electrical fires by preventing overheating of wires and other components, which can occur when a circuit is overloaded.

  4. Protect Other Appliances: By isolating the space heater on its own circuit, you can prevent it from interfering with the operation of other electrical devices on the same circuit, such as refrigerators, computers, or televisions.

Factors to Consider When Choosing a Dedicated Circuit

When installing a dedicated circuit for a space heater, there are several factors to consider:

  1. Circuit Capacity: Ensure that the circuit can handle the power requirements of the space heater. As mentioned earlier, a 1,500-watt space heater should be on a 20-amp circuit.

  2. Circuit Breaker: The circuit breaker should be properly sized to protect the circuit and the space heater. A 20-amp circuit breaker is typically recommended for a 1,500-watt space heater.

  3. Wiring and Outlets: The wiring and outlets used for the dedicated circuit should be in good condition and rated for the appropriate amperage. Avoid using extension cords or power strips, as they can create additional fire hazards.

  4. Placement and Accessibility: Consider the placement of the space heater and ensure that the dedicated circuit is easily accessible for maintenance and troubleshooting.


In summary, while it is not always mandatory, it is highly recommended to install a dedicated circuit for a space heater, especially one with a high wattage rating of 1,500 watts or more. This dedicated circuit helps prevent circuit overloads, ensure consistent power delivery, enhance safety, and protect other electrical devices in the building. By following the NEC guidelines and considering the factors mentioned, you can ensure the safe and efficient operation of your space heater.