What does a half-tank water heater mean? Does a half-tank water heater save electricity?

As we all know, electric water heaters are a common household appliance. They are easy to use and many people have water heaters installed in their homes. There are many types of water heaters on the market, and half-tank water heaters are one of the more common ones. So what does a half-tank water heater mean? Let's take a closer look!

What does half tank water heater mean?

When buying electric water heaters, people fall into this cognitive misunderstanding: "half-tank heating", which means only heating half of the water in the bucket.

Therefore, when choosing a water heater, many people think that the bigger the better. Since only half of it is used anyway, a larger one will be more flexible to use. However, who knows that it is not the case in actual use.

The "half tank heating" function does not heat only half of the water. Half tank heating is related to the state of the water tank. The current electric water heater has two heating rods. The larger the contact area between the heating rod and the water, the higher the efficiency. So if only one heating rod is turned on when the water heater is working, it is called half tank heating.

However, in actual use, half-tank heating is not very useful. The capacity of the water tank is fixed, and the rising temperature is also fixed.

The heating power only affects the time: W=Q=Pt, power consumption=heat=power*time. If the required heat Q is constant, the power is reduced, but the working time is extended, and the final power consumption is the same.

Does half-tank heating save electricity?

1. When using a small amount of water, the single heating rod of the half-tank heating will heat the water and discharge it immediately; the whole tank heating will heat the water near the drain outlet while also heating the water in the lower half of the tank - the heating of this part of the water is a waste. Therefore, in this case, half tank heating is more energy-saving.

2. When using a large amount of water, we need to heat the whole tank water. At this time, the power consumption W = calorific value Q = Pt - we have explained this formula above. Although the power of half tank heating is low, the time is long. Therefore, at this time, half tank heating does not save electricity.

PS: All of this is based on the premise that the water temperature in the electric water heater is at room temperature - that is, the water heater is not turned on in advance, and the water needs to be heated while it is used. If the electric water heater is turned on in advance, or the water heater is not turned off all year round, or the water heater is turned off but there is still hot water in it - in these cases, there is no need to use the half-tank heating function.

The role of half-tank heating in water heaters

The half-tank heating function does not save electricity. Anyone who has read the instruction manual knows that when half-tank heating is introduced, it is turned on for a short period of time and with a small amount of water. What does it mean?

That is to say, this water heater was not working before. Now if you only need a little hot water, you can turn on the half-tank heating function, only heat the water near the water outlet, drain the water immediately after heating, and turn off the power to the water heater after using the water.

If we turn on both heating rods at the same time, too much hot water will be produced, and we will not use it all. The remaining water in the water heater will gradually cool down, resulting in a waste of hot water.

Therefore, "half-tank heating" has only this one common function, and there is no need to choose a certain water heater because of this function.