There are many different types of water heaters on the market today. Modern technology means that you really have your pick of the litter when it comes to the way in which you choose to heat water for use throughout your home. Sometimes, the classics are classics for a reason. In the case of the tank water heater, it is for many reasons.
Tank water heaters are more efficient than ever before, cutting down on standby energy loss thanks to improvements in tank design, manufacturing, and insulation. They are also quite affordable up front, and are great for homes with high hot water demands as they maintain a reservoir of hot water at the ready. Like any type of system, though, there are potential drawbacks. One to keep in mind is scalding.
The Problem with Temperature Control
As a general rule, new water heaters are programmed to maintain temperatures of 120°F. Because this is determined to be a safe temperature for using hot water throughout a house, many homeowners mistakenly believe that keeping the thermostat control on the water heater at this temperature eliminates the risk of serious burns or scalding. But this is not the case.
In truth, the thermostatic control on a water heater should not be used to control the final temperature of the water to the point of use, be it a shower, sink, etc. Just think about the way in which you use hot water throughout your house. When you hop in the shower, do you dial the hot water up all the way? Of course not! Because of issues such as differences in temperature between water at the bottom of the tank and at the top of the tank, the thermostat readout on the system is not the final point of consideration when considering actual water temperature.
One of the most common issues leading to scalding with tank water heaters is “thermal stacking.” This occurs when there is short draw on hot water usage in the home, and cold water is pulled into the bottom of the tank. The burner comes on to heat this cold water, causing a spike in temperature in the water at the top of the tank. When calling for hot water in the shower when such stacking occurs, the user could experience much hotter temperatures than expected.
Should another member of the household use a significant amount of cold water when someone is in the shower, such as when flushing a toilet, the hot water in the shower may spike. So how do you protect yourself from such issues?
- Do not rely on the thermostat controls on your water heater as a defense against scalding.
- Consult with a qualified plumber about safeguards, which may include the following:
- Temperature actuated mixing valves automatically regulate water temperature according to preset temperature preferences.
- Automatic compensating mixing valves that blend hot water with sufficient cold water for safe temperatures.
- Temperature limiting devices, installed at points of use.