Abstract: A prescription lens insert and methods of use are described, in which flexing a frame of a prescription lens insert, such that left and right rims of the frame are displaced mediolaterally, aligns respective larger ends of two keyhole apertures of the frame with left and right mushroom-shaped connector pegs protruding rearward from a pair of protective glasses. The prescription lens insert is then placed over the left and right connector pegs, such that distal heads of the connector pegs pass through the two keyhole apertures of the frame and the keyhole apertures are disposed adjacent shaft portions of the connector pegs. The frame of the prescription lens insert is then unflexed to align respective smaller ends of the two keyhole apertures with the left and right connector pegs, such that the distal heads prevent removal of the unflexed frame.

Abstract: A device for controlling an HVAC system in which opening a door or window for more than a shutdown delay period causes the fan and compressor to be deactivated, but opening and closing the door or window for less than the shutdown delay period does not affect the fan and compressor. Reactivation of the compressor is delayed for a startup delay, in order to avoid overcycling of the compressor and the additional wear and tear and maintenance that would be caused thereby. Preferably, the door/window sensors are wireless for ease of installation and maintenance. Optionally, an occupancy sensor and occupancy timer are provided to turn off the system if the room is unoccupied for an unoccupied delay time. Optionally, a secondary thermostat with energy saving settings is provided so that if the room is unoccupied for the occupancy delay, then instead of being shut off, the HVAC system will be operated at energy saving settings.