FDI (Floor Drop In Heater) is a “versatile, universal size”, draft barrier heater for large window areas, sliding glass doors, entryways, hallways, open stair wells. It's simple to install, just cut a hole between floor joists in either direction (parallel or perpendicular to joists). Rough-in separate housing... then simply insert “plug-in” type heater element and fan assembly. The thermostat kit easily installed in heater
under the grille. When heater is installed for overall room heating, use a wall thermostat.