Problems of Leaving your Electric Heater On for Hours If you leave your heater on all day, your home will become too hot. Then, you would have to open your windows to lessen the suffocation, which would again lead to fall in temperature, and you would have to reheat your house all over again.
Recommended Usage Times. During the Day: It's generally safe to run your space heater for 6 to 8 hours during the day while you're home and active.
If you are using your home's furnace, no matter the type, keeping it running throughout the day and night is fully safe to keep your home at a comfortable temperature.
According to the Consumer Product Safety Commission, space heaters are involved in more than a thousand home fires every year.
Fires are one of the biggest risks associated with leaving electric heaters on all night. If an electric heater has frayed wiring or malfunctions, then there is a high chance of it igniting. Electric heaters also make the air in the room really dry by conducting a lot of heat.
Avoid the carbon monoxide poisoning by turning off the heater and unplugging it before leaving the room or going to the bed. Signs of too much carbon monoxide in the rooms include headache, dizziness, abdominal pain, discomfort, vomiting, nausea and weakness.
The good news is that modern infrared heaters are very safe to use even when left unattended during the night, even while you are sleeping.
2. Never leave a space heater running overnight. Space heaters are only meant to run for a few hours, and you should never leave one running overnight. The risk of it falling over, shorting out, or catching your room on fire are just too great.
If the unit is left unattended or placed too close to flammable materials, such as curtains or bedding, it can ignite and lead to a devastating fire. To avoid this danger, always keep a clear distance of at least three feet between the heater and any combustible objects.
Using a space heater overnight carries risks like overheating or tipping over, which are fire hazards, especially when left unattended.
What is the safest heater to leave on overnight? While it's not recommended to leave any space heater on if you're not monitoring it, oil-filled, radiant space heaters are considered safer than ceramic convection (hot air) types, according to Roberson. Both of these options are safer than open-coil heaters.
It's More Advisable to Turn the Heat Down, Not Off
If you really want to save money and avoid the problems associated with turning off the heat at night, what you should do instead is just turn it down.
You can leave them on indefinitely. I have one in our upstairs bathroom that I never shut off. It has a thermostat that keeps a very even temperature. The benefit of an oil-filled radiator type heater is that it never gets hot enough to ignite drapes or paper.
Overusing the heater or using an oversized heater can result in elevated levels of carbon monoxide or nitrogen dioxide fumes in the air. These fumes can cause cold or flu-like symptoms, headaches, and eye, nose and throat irritation.
Leaving your home's furnace running day and night is expected and fully safe to do. However, many homeowners also use alternative heating systems, including space heaters and electric heaters, which are not safe to use when unattended (like at night).
Although many people believe that it is more costly to turn your AC on and off vs. leaving it on, this is entirely false. People often base this belief on the idea that powering on your system requires a burst of energy, so leaving it running would minimize energy usage by reducing these bursts.
It's a Fire Hazard
Leaving your electric heater on all day is also a fire hazard. If you are not home to monitor the heater, it could overheat and start a fire.
A Leading Cause of Fires
The Consumer Product Safety Commission reports that approximately 1,200 fires a year are caused by portable electric space heaters.
Improperly maintained or faulty fuel-burning heaters can release carbon monoxide gas, which is odourless and colourless. Breathing in high levels of carbon monoxide can lead to carbon monoxide poisoning, resulting in symptoms like headaches, dizziness, nausea, and can even be fatal in extreme cases.
Also, most room heaters should not be left on through the night. Oil-filled room heaters are a good option if you are looking for something that you can use through the night, as they emit warmth even after they shut off.
The duration for which you can leave a space heater running depends on the time of day and your specific needs. During the Day: It's safe to leave your heater on for 6-8 hours if you're in the room. If you're busy or moving between rooms, consider using a timer to automatically shut it off after a few hours.
Ultimately then, the key to cost effective home heating isn't to leave the system on all day every day. It will save you money in the long run to properly insulate your home, ensuring you won't need to use as much energy to keep your home at a comfortable temperature.
While there is much debate about this topic, the general, expert consensus is a resounding “no” — and you should never leave it running overnight. “No, it's absolutely not safe to use a space heater at night,” states Glenn Gault, CEO at Gault Heating & Cooling.
Sealed combustion heaters are much safer to operate than other types of space heaters, and operate more efficiently because they do not draw in the heated air from the room and exhaust it to the outdoors. They are also less likely to backdraft and adversely affect indoor air quality.