A large gas canister typically lasts for approximately 8 to 12 hours when used continuously. This duration can vary depending on the size of the canister, the efficiency of the device using the gas, and the power setting of the device. For instance, a 16.4-ounce (480ml) canister of butane gas can last up to 8 hours when used at a medium to high power setting in a portable stove or heater. The duration is shorter when the device is used at a high power setting or when the canister is smaller, such as a 10.2-ounce (300ml) canister, which may last only 4 to 6 hours under similar conditions.

The longevity of a gas canister is influenced by several factors. First, the size of the canister directly impacts the amount of fuel available. Larger canisters, such as those holding 16.4 ounces or more, provide a longer burn time compared to smaller ones. Second, the efficiency of the device using the gas plays a crucial role. Devices with better insulation and more efficient combustion systems can extract more heat or power from the same amount of fuel, thereby extending the canister's lifespan. For example, a high-efficiency portable stove can extract more heat from a canister than a less efficient one.

According to a study by the U.S. Department of Energy, the efficiency of a portable stove can vary significantly, with some models being up to 50% more efficient than others. This means that a more efficient stove can provide the same amount of heat for a longer period using less fuel. Additionally, the power setting of the device also affects the duration. Using a device at a lower power setting can extend the life of the canister, as less fuel is consumed per hour.

In conclusion, the duration a large gas canister lasts depends on the size of the canister, the efficiency of the device, and the power setting. By choosing a larger canister, using an efficient device, and operating the device at a lower power setting when possible, users can maximize the lifespan of their gas canisters.