Fire safety experts and consumer protection agencies, including the Consumer Product Safety Commission, strongly advise against leaving a space heater on all night. The risk of a fast-moving fire occurring while you are asleep is significant, as you may not wake up in time to react to danger.
Never leave a space heater running for long periods of time, and especially not overnight; it is best to use them intermittently; depending on your situation, a suggested practice would be to turn it off/unplug it for 10 minutes every hour if you depend on its use for longer periods.
Most indoor heaters tend to dry out the air, lowering indoor humidity levels. Dry air can cause irritation to the respiratory tract, leading to symptoms like dry throat, cough, and nasal congestion. For individuals with chronic respiratory diseases like asthma or COPD, low humidity can exacerbate symptoms.
Recommended Usage Times
At Night: If you choose to use your space heater overnight, it's best to limit its operation to 4 to 6 hours on a lower setting.
It is not safe to run a space heater overnight. If you use an electric or propane space heater during the day, make sure to protect yourself and your home by following all safety practices. Use space heaters that automatically turn off if they tip over.
It's not recommended to leave any space heater on if you're not monitoring it. But if you must, oil-filled, radiant space heaters are considered safer than ceramic convection (hot air) types, according to Roberson.
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.
Many of the space heaters we've tested are claimed to heat only about 150 to 200 square feet. Most use 1,500 watts when on the highest heat setting, which comes to about $2.10 per 8-hour day or about $64 a month, based on the average cost of electricity nationally.
Is 72 a good temperature for heat in the winter? While slightly higher than the typical energy-saving range of 68°F–70°F, 72°F still offers a reasonable balance between comfort and efficiency.
Always turn off space heaters when not in use.
However, if you need to keep large areas warm, your home heating system will do the job more efficiently. If shopping around for a space heater, look for one that has guards from heating elements and automatically shuts off if it is tipped over or overheating.
For individuals with COPD, temperatures below freezing (32°F / 0°C) are considered too cold and can trigger severe flare-ups, chest tightness, and shortness of breath. Even temperatures dropping below 40°F (4.4°C) can cause the dry, chilled air to irritate overly sensitive airways.
It takes time for your home to warm up and cool down. If you're not sure how long it takes, try turning the heating on about 30 minutes before you need it. You should turn it off 30 minutes before you'll stop needing it.
A COPD flare-up (exacerbation) is triggered by increased airway inflammation, most commonly from respiratory infections (viruses/bacteria), exposure to air pollutants, smoke, and extreme weather. These incidents cause a sudden worsening of symptoms—such as increased coughing, wheezing, and breathlessness—lasting two or more days.
The Risk of Space Heater Fires
One third of fires in the home are caused by space heaters.
Using space heaters safely
Turn off a space heater when you leave the room or when you go to bed. Never leave a space heater unattended or running while you sleep. Put heaters on a level surface away from places where someone might bump into it and knock it over.
It only takes seconds for a fire to start if a space heater tips over or comes in contact with something combustible, like a blanket or curtains. If you're using a space heater, switch it off before leaving the room.
Heating will produce a low RH whereas the cooling is almost fully saturated air, the extra humidity during cooling will make it feel colder than the 72 setpoint due to wet bulb temperature....... The dry 72 degrees setpoint during heating season will feel closer to actual temperature due to lower humidity.
The cheapest temperature to keep your house in winter is 68°F (20∘C20 raised to the composed with power C𝟐𝟎∘𝐂) while you are home, and lowering it to 61°F–65°F when you are away or sleeping, according to the Department of Energy. Setting your thermostat back 7°–10°F for 8 hours can save up to 10% a year on heating costs.
These policy recommendations are aligned with many of the goals identified in the 2022 California Extreme Heat Action Plan (EHAP). The state should consider a general maximum safe indoor air temperature of 82 degrees Fahrenheit (27.8 degrees Celsius) for residential dwelling units.
In most homes, Heating and Cooling (HVAC) systems drive the highest energy costs, accounting for nearly 40% to 50% of your total electricity bill. Following these, the appliances that run up your bill the most include water heaters, refrigerators, and laundry machines.
At the national average electricity rate of $0.17 per kWh, running a typical space heater costs approximately $0.26 per hour, $2.04 per day (8 hours), or $61.20 per month.
Heating and Cooling
HVAC systems are typically the largest driver of energy costs. Running your furnace or AC more often in extreme weather can exponentially increase your monthly bill. These costs can make up more than half of your total electricity bill.
Stoves and ovens (cooking equipment) are the leading cause of house fires. According to the National Fire Protection Association (NFPA), cooking is the number one cause of home fires and injuries, primarily due to unattended cooking, grease buildup, and human error.
The safest heaters to leave unattended are oil-filled radiant heaters (like the DeLonghi Radia S or Pelonis oil-filled radiators) and smart ceramic heaters (such as the Dreo Solaris 718). These appliances use enclosed heating elements and include built-in fail-safes to prevent fires.
While cozy heat sources can make winter more comfortable, prolonged or repeated heat exposure can cause lasting skin damage. Be mindful of how long you're using heating devices, and give your skin time to cool off between uses.