Our professional answer after crunching the numbers? No, unless you're going on vacation for a month or longer, you shouldn't turn off your water heater.
There's no harm to turning off your hot water heater if you want. You'll just have to light it again when you get home. People are probably advising you to leave it on pilot so you can just turn it back up when you get home.
Unless you'll be vacating your home for a month or longer, turning off your water heater is unnecessary.
Else, if you have a full water tank, and you need to turn off the water for an issue unrelated to your water heater, then it really doesn't matter if you turn the water heater on or off.
Regardless of the season, you should ensure that your main water supply is turned off before leaving for vacation. However, in winter, you should be more vigilant. During this season, the water inside water pipes may freeze.
If boilers didn't come with a host of sensors and controls, it might indeed damage your boiler if you turned it on with no water to heat up. Your combi boiler would be the worst affected, as the heat exchanger could suffer, but your cylinder and radiators would probably be fine.
For short downtimes (a few weeks), flushing or draining might not be necessary. If idle for months, flush every six months at least.
For Gas Water Heaters: Turn the knob on top of the thermostat clockwise to the off position. The thermostat is located near the bottom of the water heater. For Electric Water Heaters: Go to your circuit breaker panel, find the breaker for your water heater, and switch it to the off position.
Turn the handle on the water valve CLOCKWISE until it stops. If the water does not stop, turn off the main water valve for the entire house.
Cons of turning off your heater:
It results in no hot water in your water supply when you need it. You may also encounter difficulties turning the power back on, delaying the use of warm water.
Your hot water heater might keep turning off due to several reasons. If it's a gas water heater, it could be due to issues with the gas supply, a dirty or damaged thermocouple, or a clogged pilot tube. If it's an electric water heater, it could be due to problems with the thermostat or heating elements.
If you're expecting to install, repair, or replace your water heater, then either you or the technician can turn it off before performing the service needed. There are very few cases in which a water heater needs to be turned off.
Overall, it's actually best to keep your hot water heater on when you are away from your home for extended periods of time. While turning down HVAC systems and limiting electrical use could provide some savings during a vacation, turning off your water heater could cause more harm than good.
“No heating and hot water is considered as an emergency and thus should be resolved within 24 hours as an acceptable 'reasonable time'.”
Vacation mode is a setting on your water heater system that allows you to run your boiler at lower temperatures than normal, saving energy. Typically, manufacturers set vacation mode to 50° F—well below the warmth you need to heat your home, but hot enough to prevent any water from freezing while you're away.
First, locate the temperature dial on your gas water heater and twist it into the off position. Look around the top of the water heater to find the supply line and switch off the valve to stop any more water from flowing into the heater.
Well-maintained traditional gas and electric hot water heaters can last 8-12 years, or more, before it's time for a hot water heater repair or replacement. Turning off your unit while you'll be away— or anytime your main water supply is off— is a good way to prolong the life of your system.
The short answer is yes, as long as you don't mind using cold water. Shutting off the input to your water heater will not affect your home's main water supply. You can still run appliances like your washing machine or dishwasher, flush your toilet, and use your shower, sink, or garden hose.
In fact, most water heaters' heating elements will only last a few hours or even minutes without water. Operating a water heater without water leads to rapid overheating and damage to the heating element, significantly shortening its lifespan.
This is a very common energy saving myth. But in fact, you really don't need to be heating your water all the time.
Sediment can build up over time in a water heater, shortening its lifespan. To prevent this, you should flush your water heater at least once per year. Flushing will help to remove any sediment that has built up and improve the efficiency of your water heater.
It is always advisable to turn off your water supply before leaving for a vacation. Shutting off the water is crucial for protecting your home from water damage through leaks or burst pipes. The last thing you want is to find the house flooded and with a foul smell when you return.
Shut Off the Water
This step isn't necessary for a short getaway, but if you will be gone a week or more it is a good practice to get into. It's best to turn off the water main but if you have appliances like an ice maker that need water regularly you can still turn off the water to your bathroom toilets and sinks.