Sleeping with a heater or blower on? Health risks you must know

According to a January 2025 report published in the Kashmir Observer, doctors in Kashmir issued warnings about the dangers of using unvented gas heaters in closed spaces, noting that toxic combustion byproducts like carbon monoxide can accumulate silently and pose a deadly risk, especially while sleeping.
This is a major issue in fuel-burning heaters. Such heaters produce carbon monoxide (CO), a colorless, odorless gas that can accumulate in poorly ventilated rooms. Even low-level exposure to CO overnight can lead to headaches, dizziness, nausea, and fatigue, while higher concentrations can be life-threatening.