Is it costly to leave the water heater on all day?

I want to keep the water heater on continuously so there’s always hot water when needed, but my wife says that’s not energy-efficient and suggests turning it on only 10-15 minutes before use. Let’s hear what the experts say 👇

Many people have the habit of leaving the water heater on all day to avoid waiting and have hot water immediately when they come home. This practice not only wastes electricity but also significantly reduces the lifespan of the device.

A typical water heater consumes 2,200W-2,500W of power, and its operation principle is to heat a coil inside the tank to warm up the water. Usually, the water heater has a thermostat that automatically turns off when the water reaches a certain temperature (this temperature can be adjusted by the user).

However, if left on, the water will gradually cool down, and when the temperature drops, the thermostat will kick in, restarting the heating process. This cycle repeats until the power supply to the heater is completely cut off. Therefore, if the water heater is left on all day, it will certainly cause excessive electricity consumption.

Additionally, keeping the heater on 24/7 can damage the heating coil quickly because it is constantly in operation. This is also the main cause of electric leakage. Parts like the heating element and the tank itself wear out faster as well.

To use the water heater more efficiently and safely, simply turn it on 10-15 minutes before use. Instead of leaving it on all day, if you want to use it in the morning, turn it on about 20 minutes before use and turn it off before going to sleep, so you’ll still have hot water the next morning. Typically, a 20-30 liter water heater is sufficient for 2-3 people for showering and cleaning (not considering bathtub use).

Here are some tips for using a water heater efficiently and safely:

1. Always turn off the water heater before using it to avoid electric leakage and ensure personal safety.

2. Install a grounding wire and check its condition regularly to ensure safety during use.

3. Perform periodic maintenance to remove calcium buildup (usually every two years).

4. Use the appropriate size for your needs (a 15-20 liter heater is suitable for 1-2 people; a 20-30 liter heater is good for 3-4 people).

5. Turn on the water heater 10-15 minutes before use.

6. If you want hot water quickly, it is better to use a direct water heater. This type does not have a tank like indirect heaters and heats water directly, so there’s no waiting, but it does not provide hot water to store like an indirect heater does.