Natural Gas Tankless Water Heater Showdown: 3.6 GPM vs. 80k BTU (Surprising Efficiency) We've put the Natural Gas Tankless Water Heater to the test, and the results are anything but ordinary. While the 3.6 GPM model promises efficient performance for everyday use, its 80,000 BTU counterpart delivers a punch of power that surprised us. The showdown revealed that both units excel in energy savings, but their strengths lie in different scenarios. The 3.6 GPM version is ideal for households with moderate hot water needs, offering consistent heat without breaking the bank. However, the 80k BTU model, with its higher output, proves that more isn't always less-it's a game-changer for high-demand setups. What's truly remarkable is how both units maintain their efficiency without the bulk of traditional tank systems. Whether you prioritize steady flow or robust heating, this tankless heater redefines convenience, making us rethink what "instant" really means in modern home solutions.