Can You Leave A Space Heater On All Night? 8 Safety Tips

GiveBest PCT-905 Portable Electric Space Heater with Thermostat

Space heaters are an effective way to heat a room throughout the cold months.

There are loads of options available, with portable or fixed heaters to suit a variety of homes.

However, some people have questioned whether space heaters are safe to be left on all the time and can you leave a space heater on all night?

This guide will explain the best way to use a space heater safely to get the maximum benefit in your home.

Can You Leave a Space Heater on All Night?

(4 Reasons Why You Should Not)

Let’s start with the big question, can you leave a space heater on all night? The majority of modern space heaters are designed with safety features that will cause them to automatically shut down if they are overused. This means you can technically run a space heater for an extended period of time without any safety concerns, but that doesn’t mean you should.

There are many good reasons not to use a space heater while you sleep, and we definitely don’t recommend it. Here’s a quick breakdown of why:

Can Easily Cause Home Fires

While most modern space heaters have built-in safety features to mitigate the risk of fire, older models don’t, and they can pose a real fire risk if left unsupervised. If the heater falls over or a component malfunctions, then it can be hazardous.

Over 65% of space heater fires occur when the unit is left on overnight, and it just isn’t worth the risk. On the other hand, if you use the space heater for 2-3 hours before you go to bed, there should be enough warmth to see you through until morning.

Can Emit Dangerous Carbon Monoxide

Carbon monoxide can be deadly in the home. It gives off no smell, and there’s no signal showing you that it’s there… it will just make you slip into unconsciousness, and without proper ventilation, you might not wake up.

Space heaters can give off carbon monoxide as a by-product, and if you leave it on overnight, it could literally kill you in your sleep. It’s worth switching it off before you sleep and installing good carbon monoxide alarms, which will go off if there’s a leak.

Can Cause Dry Skin

Overexposure to a space heater can dry out your skin and strip it of the moisture which helps to keep it healthy. The dry air around you can also give you a sore throat if you leave the space heater on overnight.

Better Solutions Exist

One of the key reasons not to leave your space heater on overnight is that you shouldn’t need to. If you have decent insulation, you should be able to run it for a few hours before bed, and the heat will keep you warm all night. You can also invest in other types of heating, such as oil heaters, which are ideally suited to be left on overnight.

How Long Can a Space Heater Be Left On?

You should never leave a space heater on overnight, but that doesn’t mean you can’t leave them running for extended periods. They are designed to be safe to use for hours on end, and the truth is that most modern models can handle it.

You should always buy an appropriately sized space heater which is suited to the room it’s in. This all comes down to the wattage of the unit, and as a general rule, it takes 10 watts to heat 1 square foot of space. That means for a 50 square foot room, you’ll want a space heater with 500-watt power.

A fully functioning space heater shouldn’t take more than 2-3 hours to heat a room. You can leave it on all day, but if you feel you need to, then you may need to invest in better insulation. Our advice would be to use it only when you need to so you can keep your energy bills down and avoid paying a fortune.

How To Safely Use the Space Heaters

(8 Safety Tips)

Over 50,000 house fires are caused each year, with over 40% of these being directly linked back to space heaters. We’ve talked a lot about safety in this article because the truth is that most modern space heaters are built to be intelligent and safe.

If you know how to use the space heater correctly and responsibly, then you shouldn’t have any issues. Here are some top safety tips to keep you and your family safe:

1. Don’t Leave On Overnight

We’ve covered this already, but don’t leave your space heater on overnight, or it can be a safety hazard for you and your family.

2. Remove Flammable Materials

Your space heater will heat the immediate area around it very quickly, so it’s vital that you move any flammable materials, so they’re at least 3 feet away from the device. This will limit the risk of anything catching fire in your home.

3. Check Before Use

Proper maintenance of the space heater is vital so you can make sure it’s all working correctly. Always check the unit over before you switch it on to see if any dust, dirt, or debris might impact the performance. You can also check to see if there are any loose components that might need to be replaced.

4. Supervise During Use

You must keep an eye on the space heater while it’s in use too. Make sure nothing flammable has fallen too close to the heater, and check the power outlet cable regularly. If the cable is hot, it means the device is working too hard and has potentially been on for too long, so you should turn it off.

5. Place On Stable Surfaces

The last thing you want to do is place your space heater on an unstable or unlevel surface because this increases the risk of it tipping over. If your heater tips over, it can cause the device to overheat and potentially cause a fire in your home.

Most modern models are equipped with tilt detection, so they automatically shut off if it falls over, but older models won’t have this functionality.

If it keeps on shutting off though, then there most probably a problem with the space heater.

6. Remove Water Sources

Space heaters are electricals and should therefore be kept away from water. Water on the device can damage it or potentially cause an electric shock.

7. Install Carbon Monoxide Detectors

Carbon monoxide is so dangerous because we won’t even notice it’s there. You should install carbon monoxide detectors so you know if the space heater is leaking any harmful gases.

8. Don’t Overuse

Don’t leave your space heater running for too long. This increases the risk of an electrical fault and will drive your bills up massively. You shouldn’t need to use it for more than 2-3 hours at a time, and any more could impact the longevity of the device.

Do Space Heaters Turn Off Automatically?

Sample of an Energy Efficient Space Heater

Modern, high spec space heaters are equipped with automatic shut-off, but older and cheaper models won’t have this functionality.

This means that you can’t rely on your space heater shutting off automatically, and even if it is built-in, there can be some issues with it.

There are three main safety features built in to keep you safe:

Timed Shut-Off

This function involves a timer so you can set how long the space heater will run. This, in theory, allows you to leave the house or room with the space heater running, but we wouldn’t recommend leaving it unsupervised. This timed shut-off is a great way to limit the amount of money you’ll spend running the heater.

Over-Heat Sensors

This function helps to mitigate the risk of your space heater causing fires because it senses the temperature around the heater. If it gets too high, the device will automatically shut off and, hopefully, prevent any home fires.

Tip-Over Sensors

Tip-over sensors will automatically switch the space heater off if the device falls over. If your heater isn’t properly positioned, it will trigger an automatic shut-off to prevent any risk of a fire.

All of these safety features are useful, and they can give you a bit of added peace of mind, but you can’t always rely on them. One of the biggest risks to a space heater is a malfunction, and if this happens, then these safety features may not even be triggered. Our advice would be to monitor the device yourself and use it responsibly.

People Also Ask (FAQ)

Are space heaters safe to leave plugged in?

Space heaters should be fine to leave plugged in, but you are better off unplugging it completely when it’s not in use. You should never use a space heater on an extension cord.

Do space heaters turn on automatically?

No, your space heater will need to be turned on manually unless it’s equipped with a timer.

Is it cheaper to keep your central heating on low all day?

Space heaters are more expensive than central heating, but by using them in controlled bursts, it can be more cost-effective than leaving your central heating on all day.

What should you set your central heat on at night?

You should set your thermostat to around 8 degrees lower at night to help you sleep well. That means you should aim for between 62- and 70-degrees Fahrenheit at night.


Space heaters have a reputation for being dangerous, but most modern models are as safe as any other type of heater if you use them correctly. Hopefully, this article has helped you understand the risks and what you can do to help mitigate them and keep you and your family safe.

Last Updated on March 9, 2023

Josh M