AZ Patio Heaters Residential Quartz Glass Tube Patio Heater in Black. Add this beautiful unit to your backyard oasis you are sure to amaze your friends and family. This masterpiece not only provides 41 000 BTUs of raw heat it also creates an astonishing ambiance for all to enjoy. While being functional and beautiful it also important to be safe this unit is equipped with a thermocouple to ensure the unit is running at a safe temperature and an anti-tilt switch that will shut the unit down in case of a tip over while it is in operation. You will surely enjoy this unit for years to come.