With temperatures dipping below freezing across the United States, older furnaces can have trouble keeping homes comfortably warm. To add heat, people use unventilated or portable gas heaters, often called "space" heaters, kerosene heaters or salamander heaters. But are they safe? If used with common sense and following the manufacturer's instructions, the answer is yes.
Most people worry about carbon monoxide (CO) from unventilated gas heaters. There is a lower risk of CO poisoning in newer indoor gas space heaters because they have a built-in oxygen depletion sensor. If too much CO or CO2 is produced, the oxygen level in a room will lower and shut down the heater automatically.
However, older space heaters or outdoor heaters do not have any sensors. When used in enclosed spaces, CO can reach dangerous levels.
This is why no matter what kind of gas heater you have, you should keep a carbon monoxide alarm nearby. Oxygen sensors can fail, and carbon monoxide can (and does) kill. CO alarms are inexpensive, and readily available in home improvement stores. For added safety, follow the heater manufacturer's instructions carefully, and avoid using unventilated heaters when you are sleeping.
The other important thing to do is to follow the manufacturer's instructions. In regards to safety, they all make 2 important points:
The problem with keeping the room sealed up is that heat is generated from a flame, and the flame burns oxygen. Over time, if oxygen levels are depleted, CO levels will rise. CO is the result of combustion without enough oxygen.
In addition to carbon monoxide (CO), all gas space heaters produce large amounts of carbon dioxide (CO2). While not normally harmful, too much CO2 in an enclosed space results in sleepiness, and headaches.
High levels of CO2 contribute to what we often call “cabin fever.”
Here's one more reason to ventilate the room: if carbon dioxide accumulates over a long period of time in an unventilated space, the flame of the heater slowly converts carbon dioxide to carbon monoxide!
To monitor indoor CO2 levels, many people use our TIM10 Desktop Meter. If CO2 levels are high (above 5,000ppm) it is time to open a window or go outside for some fresh air.