Is It Cheaper to Set Your Water Heater Timer to “Always On”?

Water heater timers allow you to set a specific schedule for heating the water your household needs. However, they a couple of settings and there’s an argument out there that holds it’s cheaper to set your timer to “always on” rather than “clock”. Is this true? What’s the story here?

Is It True?

In a word, no, it is not cheaper to leave your timer set to “always on”. The better option is to set it to “clock” and then choose times that correspond with your usage schedule. That can be hard, since most people’s schedules vary over several days and a timer doesn’t offer a lot of flexibility, other than dialing in different on/off periods that repeat each day.

Unpacking the Myth

So, if it’s not actually cheaper to set your timer to “always on”, where did the myth come from?

In truth, it’s easy to see where this idea got started. The thought is that it takes less energy to bring warm water up to temp than it does cool water. So, if you use the “clock” setting, you’ll pay more to heat your water because it cools off more in the interim. Leaving it on ensures that the water never fully cools so you spend less energy getting it back to the right temperature.

Here’s the thing: the water in your water heater will not cool off very much even over 24 hours without additional heating. Today’s unvented cylinders are highly insulated and capable of maintaining temperature for long periods of time. Even if you have a lot of time between timer pre-sets, you will only need to heat water for a very short period to get it back to temp.

Here’s another reason to avoid the “always on” setting: it’s really inefficient. When you do that, you turn the operation over to your thermostat. It will kick on as soon as the water heater drops below temp, even if only by a degree. Then it will kick off as soon as it warms to temp. This gives you lots of very short on/off cycles, and that creates unnecessary wear on the water heater’s workings, potentially leading to premature failure and additional costs related to replacement.

Other Factors Also Affect Efficiency

A water heater timer can help you reduce your energy use and your related costs. However, it’s not the only thing that affects your system’s efficiency. Annual maintenance is important for removing sediment build-up within the cylinder and catching problems while they’re small before they turn into major issues. We recommend having your unvented cylinder serviced once per year to ensure efficiency and reliability.

Thinking about having a water heater timer installed? Need to have your unvented cylinder serviced? Want to inquire about annual maintenance? Perhaps you need a new cylinder installed. We can help in all these situations. Get in touch with the team at EasyFlow to discuss your options and learn more about our services.