What is a common preset temperature for gas-fired hot water tanks, measured in Fahrenheit?

A common preset temperature for gas-fired hot water tanks is indeed around 140°F. This temperature setting is widely recommended for several reasons. Firstly, it is hot enough to provide adequate hot water for most residential applications, ensuring that showers, dishwashing, and laundry can be performed effectively without running out of hot water.

Additionally, 140°F is typically considered a good balance between safety and efficiency. At this temperature, the risk of scalding is reduced compared to higher temperatures, especially for vulnerable individuals such as children and the elderly. However, it is still high enough to help prevent legionella bacteria growth, which can thrive in lukewarm water.

Temperature settings higher than 140°F, while effective in preventing bacterial growth, can significantly increase the risk of scalding if there aren't adequate safeguards in place, such as thermostatic mixing valves. Therefore, many professionals in plumbing and HVAC recommend 140°F as a standard for residential gas-fired hot water heaters, reinforcing its status as the most common preset temperature in these systems.