Amazon.com: Infrared Vent Free Propane Gas Heater - 20k BTU Ventless Gas Heater to Warm Your Space - Gas Heaters for Home, Garage, Shop, & RV – Propane Heaters for Indoor Use
Mr. Heater 30,000 BTU Vent-Free Liquid Propane Blue Flame Heater at Tractor Supply Co.
Dyna-Glo 30000-BTU Wall-Mount Indoor Natural Gas or Liquid Propane Vent-Free Convection Heater in the Gas Space Heaters department at Lowes.com