Why Are Water Heaters Round?

If you have a storage tank water heater, you’re probably familiar with this cylindrical appliance in your garage or utility closet. Have you ever looked at your water heater, though, and wondered why it’s the shape that it is?

Think about it – unlike other appliances in your home, your water heater is designed purely for its function. Unlike your oven, refrigerator, or even washer and dryer, the people who designed your water heater didn’t have to strike a balance between aesthetics and optimizing performance. You might even notice that every storage tank water heater you’ve seen is also a cylindrical shape.

So, what’s up with that? Well, when you consider what’s going on inside your water heater, it all makes a lot more sense.

Pressure Distribution

Think about a can of soda. Just like your water heater, this is shaped like a cylinder. This is because a cylindrical shape is both practical and able to withstand the pressure exerted in all directions by carbonated soda. In fact, a soda can that’s just a tenth of a millimeter thick can contain liquid that’s held at six times the atmospheric pressure you’re used to breathing (about 90 PSI)!

A typical water heater is designed to hold around 150 PSI of heated water, which you’ll notice is considerably greater than what a soda can must withstand. While the water heater’s cylindrical shape does a good job of keeping pressure contained, too much pressure can breach the structure and cause an explosion. This is why water heaters are equipped with pressure relief valves to keep the pressure inside under control.

Heat Distribution

Not only is a cylindrical shape useful for evenly distributing pressure, but it also helps to evenly distribute heat.

In a gas water heater, a burner at the bottom heats the water beneath it, causing it to rise. As this happens, the cooler water sinks toward the burner until it also gets heated and rises. This process works similarly in an electric water heater, which uses heating elements instead of a burner to distribute heat.

Because of a water heater’s cylindrical shape, water will get heated evenly in all directions. Any other shape would either be impractical to keep in your home (such as a spherical tank) or wouldn’t be as efficient or able to withstand pressure buildup (such as a rectangular tank).

Have Another Question about Your Water Heater?

If you have another question about your home’s water heater, don’t be afraid to ask! At Watermen Plumbing, we’re proud to be of service to our community. Rest assured that if you have a plumbing problem in your home, we have the knowledge, experience, and skill it takes to fix it.

For more information, contact us online or call (954) 800-6364 today!