Detecting fire and non-fire conditions includes receiving a plurality of frames of video information, determining an energy indicator for each of a subset of the plurality of frames, detecting a fire condition in response to the energy indicator for each of the subset of the plurality of frames forming a pattern as a function of time corresponding to a fire condition, and detecting a non-fire condition in response to the energy indicator for each of the subset of the plurality of frames forming a pattern as a function of time corresponding to a non-fire condition. Detecting fire and non-fire conditions may also include comparing energy indicators for each of the subset of the plurality of frames to a reference frame. The reference frame may correspond to a video frame taken when no fire is present, a video frame immediately preceding each of the subset of the plurality of frames, or a video frame immediately preceding a frame that is immediately preceding each of the subset of the plurality of frames.