Government regulations limit space heater output to 1,500 watts, which is not nearly enough to heat an entire home.
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.
Heaters must be kept at least three feet away from anything that can burn, including papers, clothing and rugs. Locate space heaters out of high traffic areas and doorways where they may pose a tripping hazard.
Most house circuits can only handle one space heater on each circuit, with maybe a light/radio/tv. If you want two space heaters, you want two different circuits and without a coffee pot on it either, or expect to go out in the cold.
Using the heater too often could lead to undesirable consequences like leaving out skin or nasal passages dried out. It Can Cause Carbon Monoxide Poisoning-It's important to keep your space heater in good working order so you don't have any accidents or health problems.
Running a space heater overnight increases the risk of fire. 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.
You Should Not Leave Space Heaters on Unattended
If a space heater falls over or becomes too hot from running for too long of a period of time, that can lead to a fast-moving fire that occurs while you are asleep and cannot act fast enough.
Don't use more than one heating device in a single outlet, and avoid using more than one heating device on a single circuit. If you have more than one outlet along a wall or in a room, they very well could be on the same circuit, depending on the age of your home.
On average, you can expect to pay about 20 cents per hour to run a typical space heater that's 1,500 watts and can heat a standard room such as a home office or bedroom.
One small space heater plugged in 8 hours a day can add about $50 to your monthly electric bill. Space heaters are a great way to increase the temperature in one room for a short period of time, but keep in mind that they can be costly to run and will result in a higher bill.
Using a space heater can be a good way to boost the temperature in a small, drafty room—and it could be less expensive than cranking up your central heating system. But a space heater is economical only if you use it judiciously.
Portable Heaters
Always plug electric space heaters directly into a wall outlet and never into an extension cord or power strip, to prevent overloading and causing a fire. Never leave portable heaters on while sleeping.
Put your space heater on the floor and leave it there
And definitely don't put it on top of your bed, with all those flammable fabrics and feathery fillings. If at all possible, keep it off the rug, too. Generally speaking, you should always place your space heater on the flattest, smoothest surface available.
Avoid leaving a space heater unattended -- especially for long periods. Do not plug space heaters into extension cords or power strips. Unplug space heaters when not in use.
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.
Overheat Shut-off: If the heater gets too hot, this feature will turn it off, preventing potential fire hazards. ECO Mode: This energy-saving setting adjusts the heater's power output based on the room's temperature, helping you stay warm without overheating while saving on energy costs.
Example (you can use an electric heater running cost calculator below for different wattages/kWh prices): If we assume the price of electricity is $0.1319 per kWh, a 1,500-watt electric space heater will cost; $0.20 to run per hour. $4.80 to run per 24 hours (day). $11.20 to run per week (8h/day).
If someone is at home in the daytime, 72° F (22° C) is a good start, but aim for 68° F (20° C). If everyone is away from home in the daytime or you're asleep at night, we feel 66° F (19° C) to 62° F (17° C) is best.
Using a space heater 8 hours per day will use about 84 kilowatt-hours of electricity per week. It costs an average of $51.65 to run a space heater for a month and $258.26 to run for a year. The best way to save on electricity is to install solar panels.
Overusing room heaters, especially oversized ones, can lead to elevated levels of carbon monoxide and nitrogen dioxide fumes in the air. These invisible intruders can bring about cold or flu-like symptoms, headaches, and irritating sensations in the eyes, nose, and throat.
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.
Regardless of the cost, here's the kicker: all 750-watt or 1,500-watt heaters produce the same amount of heat!
Is it safe to leave a space heater on overnight? 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.