Space heaters are rated on performance features such as heat output, circulation efficiency, thermostatic control, noise level and anti-fire safety. Since the product's benefits largely depend on the user's individual needs, many ratings also consider secondary factors, such as the heater's size and cord length.
A space heater's ability to heat a room quickly and effectively is typically the most important factor in a performance rating. Consumer research companies often rate the unit based on its effectiveness at warming an entire room compared to its speed at spot heating, or rapidly heating a person or small target area. In terms of features, ratings and reviews focus on the type of heater and whether it contains an internal fan or oscillation capabilities, both of which help the unit evenly distribute warmed air around the room.
Integrated safety features also rank high on the ratings list because automatic shutoff capabilities can prevent fires and allow users to leave a heater unattended. Space heaters generally receive higher ratings if the automatic shutoff activates when the unit tips over or builds up too much internal heat. To satisfy child- and pet-safety concerns, consumer space heaters are also rated highly when the exterior housing remains cool, regardless of how much heat the unit generates.