Can I Use A Heavy Duty Extension Cord With Space Heater?

Space heaters are ideal to use in your home for keeping you warm during the cold winter season. However, in as much as they offer the best service and convenience, you need to use them with caution and special care to avoid causing any damages.

Although it’s not recommended to use an extension cord with a space heater, there is a chance that you can still use it – but only if you’re seriously cautious. You need to pay close attention to the various safety aspects to ensure that your home is safe from potential hazards.

Here, I’ll talk about using a heavy-duty extension cord with a space heater and some of the safety precautions you have to take.

Is It Good to Use an Extension Cord with a Space Heater?

Unfortunately, you’re not supposed to use an extension cord with a space heater. This is mainly because most extension cords are not built to handle the high current space heaters draw. You should especially avoid low-quality extension cords because they can easily catch fire and result in damages to your home.

You should also never plug your space heater into a power strip because these units are not designed to handle the high current flow needed for a space heater. Therefore, they can overheat and even catch fire due to the energy flow that has been added. One crucial thing you need to know about extension cords is that they are only built to handle lower amounts of current.

It’s important to note that medium-sized space heaters can draw approximately 1,500 watts and 1.25 or more amps. When you check this number, you should know that it’s more than what most extension cords can handle. This is because most extension cords have a rating of 10A to 15A. This is a perfect example of walking on the edge of a cliff – a slight fluctuation in power can result in burning your cable and lead to a fire outbreak.

Additionally, even if you happen to have a cable that is rated 15A, the high amounts of current can heat the insulation resulting in melting. Most of the extension cords, even the heavy-duty ones, are not suitable for space heaters. They are incompatible, and it’s highly recommended to avoid such a connection.

Why you shouldn’t Use an Extension Cord with a Space Heater

Extension cords come with their downside that you need to know to clearly understand why they are not ideal to use with space heaters in your home. Below are some of these disadvantages.

1. Someone Can Trip Over Them

Having long cables in your home is dangerous because someone can trip over them. If you have kids or pets in your home, it can be quite risky. A long extension cord in your home increases the chances of someone tripping over it. This is not harmful to you and those in your home but can also cause the heater to tip over and cause severe damages such as a fire.

2. The Space Heater Might Fall and Cause Damages

When someone trips over an extension cord, it can cause your space heater to fall. If that happens, it can lead to damages due to the impact of hitting the floor, thereby resulting in burning combustible objects that might be nearby.

Although most modern space heaters have tip-over protection that turns off the heat when the unit is tipped over, as long as the heater hasn’t cooled down properly, it can still lead to a fire outbreak burn your home.

Therefore, it’s important to pay close attention to space heaters especially, older heaters that don’t have the auto shut-off. If such a space heater falls off on your carpet, it can cause a fire or leave a black stain that is impossible to remove.

3. Extension Cords Reduce the Efficiency of Your Space Heater

Efficiency is important when it comes to space heaters. Unfortunately, extension cords lower the efficiency of space heaters. This is mainly because space heaters rely on having a strong power source supplying them with plenty of energy.

However, extension cords are not designed to handle that much energy flow. Interposing the long extension cord between your space heater and wall plug may effectively increase the resistance for the flowing current.

Most of the modern supplies are designed to increase the power as needed. Therefore, when you plug in an extension cord, the power supply tends to increase the power to reach the space heater.

Although you might think that this isn’t such a huge effect, one thing you need to know is that it will end up increasing your electricity bill in the long run.

4. Extension Cords Tend to Increase Currents

Another drawdown of extension cords is that they can increase currents. When you decide to use an extension cord, the resistance it produces causes a voltage drop.

This voltage drop will end up being compensated by your power supply by delivering higher currents. You need to keep in mind that your space heater will draw approximately 1500W no matter what.

Therefore, power equals voltage multiplied by current. That means that the current will have to increase. These high currents generally cause fires, and it’s one of the main reasons you should always avoid using extension cords.

Can You Use a Power Strip with a Space Heater?

Just like extension cords, you should always avoid using power strips with space heaters. This is because a power strip can also heat up easily and melt the materials. It might even result in a fire outbreak, similar to using an extension cord.

It’s been proven that using a power strip can be more dangerous than even using an extension cord. The worst thing is plugging in your space heater into a power strip with other devices plugged into it.

The more devices you have plugged into your power strip, the more power it will use and the more dangerous it will be for you. However, a space heater already runs at the limit of what your power strip can deliver. This means that the risk of a cable overheating or your fuse melting is even bigger than using a regular extension cord.

Best Tips to Use Your Space Heater with an Extension Cord

Between the years 2011 and 2015, space heaters accounted for 43 percent of U.S. home heating and fires, and 5 out of 6 home heating fire deaths – that’s approximately 85 percent of deaths from heating and fires.

About half of those home heating fires resulted from running heaters too close to other objects like clothes and furniture. That means you always need to pay close attention to your space heater when it’s running. If you don’t have any other option and only need an extension cord, here are some tips to help you.

  • Ensure that you use a space heater able to switch between 750W and 1500W.
  • Lower power means that there is a risk of damaging the power supply.
  • When running your space heater at 750W, the increase of the current caused by the extension cord will not harm your cable since it’s within the recommended boundaries.
  • Always use a space heater when you’re able to monitor it closely. This will significantly help you to avoid dangerous accidents such as overheating and fire outbreaks.
  • Leaving your space heater unattended is a recipe for disaster. It will end up causing more damage in your home than good. Therefore, it’s important to keep that in mind when you purchase a space heater.

Is My Extension Cord Safe?

Running your extension cord with too much power, your cable may heat up. Typically, the thinner your cable, the hotter it will become. This happens because thin cables increase the amount of current per diameter.

When a thin cable faces many currents, it can cause a large number of electrons to bump into the metal atoms of the extension cord. These atoms will then begin to wiggle around and cause heat.

The unfortunate fact is that most of the extension cords that look thick aren’t suitable for high-power applications. Some manufacturers use a lot of insulation on extension cords to make them look thick to save money with thin copper wires. A thick cable stays cool since there is more space for the current to travel.

Heavy Duty Extension Cord

If you need to use an extension cord with your space heater, it’s important to consider using heavy-duty extension cords. These cords are well built to handle the current drawn by high-power devices. However, you still need to ensure that you’re safe even when using a heavy-duty extension cord. You can do that by running your heater on low power settings.


It’s not recommended to use an extension cord with your space heater since there are too many drawdowns. However, if you don’t have any other option, try to limit the space heater’s power to 750W or even 1000W. This is a safer approach to heating your room with an extension cord.

If you have any questions regarding this post, feel free to send them in the comments section below or reach out to me through email.