Under Desk Heater. You can keep it on or under your desk without fear. Since under desk heaters use maximum currents allowed in the room there is a higher risk of wires overheating and catching fire.
This heater stands less than 8 inches tall and uses about 200 watts of energy. Free shipping by amazon. First unless you keep turning the heater off every time you leave the room it will continue to consume energy.
So using extension cords could create a fire hazard.
Lasko s model 100 heater will come to your rescue. This panel heater stands up on two feet and measures 21 inches in length and 15 inches in height so it covers a good amount of area for heating. Second this type of heater is relatively large. Office heaters are usually flat panel radiators designed to fit under a desk.