Sunpak Heaters can effectively heat outdoors because they warm people with infrared radiant heat instead of hot air. Radiant heat warms people and objects such as tables, chairs, and floor directly without heating the intervening air. Turn the heaters on to HIGH to warm up a chilled patio and adjust the heaters down to LOW as your guests get comfortable. Proper patio layout and design are important with any patio heating system. We always recommend working with a professional installer to maximize coverage and ensure safety. Each Sunpak heater is CSA designed and certified to rigid ANSI standards.