Tank vs. Tankless Water Heaters 

When it comes to choosing a water heater for your home, it all boils down to two options. You can either get the traditional tank heater or the space-saving tankless water heater. 

While this may not sound like a tough choice, with one tank taking up considerably less space in your home than the other, size isn’t the only factor you should consider.

How They Work

Tank water heaters are by far more common than tankless ones, mostly because they’ve been around longer. So not many people know much about tankless water heaters, although they’re slowly gaining popularity and market share.

Tank Water Heaters

When people think of water heaters, they think of traditional storage tank heaters. These tanks generally hold anywhere from 30 to 50 gallons of water, depending on their size. 

Usually, tank water heaters run using electricity, propane, natural gas, or oil. Water fills the tank and is heated and kept warm until it’s needed. These water heaters have been the industry standard for generations, which makes them ideal for older homes.

Tankless Water Heaters

Tankless water heaters are often referred to as “on-demand” water heaters for their ability to provide hot water the moment you need it. They are the newest tech in hot water heating. As the name suggests, there’s no tank involved in these systems, so it takes up far less space in your home than a traditional tank-based water heater. 

These water heaters are ideal for large families where there’s high demand for hot water. Between laundry, showers, and food prep, tankless water heaters rise to the demand. 

How They Compare

To further understand the differences between these two water heater varieties, it helps if you look at them side by side. There are three main areas where the differences between them become apparent. 


Tank water heaters typically don’t require any wiring or piping modifications to your home. These heaters cost less than the tankless variety and are cheaper to install. 

On the other hand, tankless water heaters cost more upfront for the unit and the installation. That winds up balancing out by the money they save you later on, but the upfront costs can be a deciding factor for some, so it’s worth mentioning. 

These space-saving heaters can easily fit into your home under sinks, on walls, and in small, discreet places where they may go unnoticed. While they’re easy to install in newer homes, tankless water heaters pose challenges to older homes.


This is where tankless water heaters shine. While they cost more upfront, the amount they’ll save you on your monthly electric bill helps make up for it. Tankless water heaters are around 30% more efficient than storage tank units. Since these heaters only heat water when there’s a demand for hot water, they sit idle the rest of the time. 

Storage water tanks collect water and keep it warm, even when no one needs it. If the water temperature cools below a specific set temperature, it gets reheated to ensure that the water is always within a particular parameter. While this is certainly appreciated when it’s time to shower, it’s a waste of energy for all the hours of the day where you don’t need it. 


You won’t even notice a difference when you first turn on the faucet. Hot water will be ready and available on command. It’s not until you need it several times throughout the day that you may see a difference between these two heating types. 

Storage tank heaters that are adequately sized for the household they serve rarely run out of water. However, when they do, there’s nothing you can do but wait. There’s no instant refill. 

Tankless water heaters boast never-ending hot water as they heat water instantly as it passes through. While this is true, it doesn’t account for demand. If someone is showering and someone else is doing laundry, the heater may not be able to keep up, slowing down the flow of hot water in your home.

Find Plumbers Near Me

If you live in the beautiful Bay State in or near Framingham, MA, and you find yourself in need of a water heater upgrade or replacement, you’re in luck. The plumbing experts at Sharp Plumbing & Heating in Framingham, MA, are here to help.  Check out our plumbing blog to learn more about this commitment or catch up on the latest industry news and service projects. Contact us today to talk to a team member and see how we can help you with your water heating needs.

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