Shutting off your water heater for when you’re on vacation may seem like an obvious money-saving solution, but it’s not always advisable. Here’s what you need to know.
In General, Leave It Alone
If you’re turning your water heater off for vacations, you’re not saving yourself much money, and you’re increasing the risk of dangerous bacterial growth.
First, from a health standpoint keeping the water in the tank hot keeps you safe. Lukewarm and cool water temperatures encourage nasty bacterial growth. When water gets below 108 °F, for example, legionella bacteria, if present in the system, multiply rapidly. It takes hours of high heat when you finally turn the water heater back on to kill off the legionella (and other bacteria) in the tank.
Second, while shutting off your tank does save money—how much depends on the efficiency of the heater, its age, and how long you shut it off for—the savings are likely very negligible. Worse yet, you might save a few bucks on heating costs but ultimately end up replacing your water heater. It’s unlikely a relatively new water heater will malfunction after a period of being turned off, but older water heaters are usually happier kept on. Cycling from a high operating temperature down to room temperature and back up can lead to leaks or component failure.
Consider The Vacation Length
For the length of a typical vacation, it just doesn’t make a whole lot of sense to go through the hassle of turning off your water heater to save a few bucks (or even less).
If you’re going to be away from home for a multi-week or longer vacation you might consider turning the heater off or using the “vacation” mode if it has one—vacation mode keeps the heater on but significantly lowers the temperature, it’s like a compromise between paying to keep the water hot and having the components in the heater sit completely idle.
Either way, be sure to turn the heater back on as soon as you get home and remember to wait several hours to use hot water (and flush the pipes before you do) to remove any harmful bacteria in the tank.
Save Money All Year Long With Insulation
Ultimately, rather than worrying about saving a few dollars every time you’re out of town, it makes more sense to focus on saving money all year long.
Adding an insulation jacket to your older water heater and adding inexpensive foam pipe insulation to any exposed hot water pipes in your home will go much further towards saving money than fiddling with your water heater before and after vacations.