Patio Heater radiant (mushroom style) Rental. Each unit requires one basic full tank to operate for up to 6 hours. Radiant heat provides a "dome of warmth" when standing or sitting within 3 to 5 feet from the unit. CANNOT be used indoors or under a tent. OUTDOOR USE ONLY! Order three or more units to create a zone of warmth on the patio. For larger areas order the Bromic Tungsten portable.