Winnerwell is the world's first camping stove brand that originally applies the theory of External Air intake from outside the tent and hold patents in multiple countries. The External Air draw allows the stove to perform independently from the air inside the tent. This unique feature eliminates cold drafts inside the tent and prevents the stove from consuming the hot air it has just created, making it much easier for the stove to heat a tent.
All the front door air intake wood-burning camping stoves, such as Winnerwell 1G series stoves, sold in the market are for Outdoor Use Only, there will be safety risks to use these stoves in the tents with limited air ventilation because they are consuming the air that the tents' occupants to breath.
A typical stove can consume between 10 to 20 cubic meters of combustion air every hour and an average airtight 4-person tent has a volume of air around 30 to 40 cubic meters, so it's obvious that a stove operating in an airtight tent could quickly consume up the Oxygen in the tent within 2.5 hours and thus present serious problems for the occupants, especially when sleeping at night.
An inbuilt external air supply to Winnerwell External Air series stoves ensures that there's an unlimited flow of fresh combustion air, which is safer for the tent's occupants because they are not in competition with the stove for their air.