Water Heater Sizing Info

Find the size of water heater that will best fit your needs.

Bringing experience in providing innovative water heating solutions for over 73 years, State's rich tradition in the water heating industry makes them a proud leading manufacturer of water heaters for the home. Our water heaters provide the solution you need for your home and lifestyle, no matter where you live, with a range of sizes, features and capacities.

More On Water Heater Sizing

Understanding Your Hot Water Needs

To choose the correct water heater size, there are a few factors to consider. First, think through the amount of water you use and how often you use it.

A benchmark can help you determine these factors. Consider how many people live at your home and how often they take showers. Do they take back-to-back or simultaneous showers? How long is the typical shower? Does your home have bathtubs (and if so, what is their size)? You may also want to consider other appliances that require hot water, like washing machines and dishwashers, and the time and frequency those are used. For example, are they typically used during the same times you use a shower?

Considering these factors will give you the information you need to choose the correct water heater size for your home and your needs. Use our XPERT Water Heater Selection Tool for more help.

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Determining Your Priorities

Your personal priorities and your unique lifestyle choices will also help you choose the right size water heater.

There is a sliding scale between how much your water heater can store vs. how quickly it can reheat the water in its tank. The right water heater for you will strike a good balance depending on what’s most important to you and what will meet your needs.

If your needs include filling a large bathtub or allowing for multiple showers to be taken at the same time, a tank water heater may be a good choice. These units provide storage capacity, but they do take time to reheat a full tank of water.

On the other hand, tankless water heaters can produce a continuous flow of hot water, making them ideal for sustained hot water use, such as multiple showers in a row. However, tankless water heaters may limit the number of fixtures you can use simultaneously.

Learn more about tank and tankless water heaters.

Thinking through your priorities will lead you toward the best water heater type for you as well as the size that will fit your needs best.

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Your Space Requirements

Once you’ve determined your hot water requirements and aligned your priorities, the amount of space you have for a water heater can help you narrow down your options. If you have a lot of space, a large storage tank water heater may be the best solution. These can be installed in basements, closets, and other spaces that are away from where you spend most of your time.

For homes with minimal extra space, tankless water heaters can provide an efficient solution. They're compact and can fit into areas of your home like small closets. No matter your decision, ensure you’ve considered where your water heater should be installed and how much room you have to spare.

Elderly couple washing dishes.

"Instant" Hot Water

A water heater alone can't provide instant hot water-no matter if it's a tank or tankless water heater. But when the right features, capabilities, location and technology are in place, some water heaters can provide nearly instantaneous hot water. Read more to consider factors that may impact the production of "instant" hot water.

Capabilities: A built-in recirculation pump* is one example of a product feature that can help deliver hot water instantly. This feature circulates hot water to ensure it is available quickly. Unused hot water is returned to the water heater to be heated again to reduce waste.

*It may be necessary to install a recirculating piping system.

Proximity: Without a recirculation pump, the water heater’s distance from the water fixtures will impact the time it takes for the fixture to receive hot water. The hot water you need will arrive faster when the water heater is close to the fixture, as the piping is shorter between the two.

Temperature: Hot water delivery can also vary based on where the hot water piping runs through your home and how well it is insulated. Piping placed in a crawl space or attic may be impacted by seasonal temperature changes. Without a recirculation system, 40 feet of piping placed in a crawl space will take longer to produce hot water at a fixture in a northern United States winter than 40 feet of piping located in an attic during the summer in the southern United States.

How can technology help deliver instant hot water to a fixture? Learn more here.

Help Me Choose!

Looking for more help? Answer a few simple questions in our XPERT Water Heater Selection Tool, and you'll be on your way to narrowing down your search to three choices that fit your lifestyle and your unique needs.

Additional Reading

Gas water heaters require venting upon installation. Depending on your home, there are many different options.

Learn about vent configurationskeyboard_arrow_right

How can the quality of your water affect your water heater? Get tips and more information on water hardness, why it matters, and how to solve it.

Learn how water quality affects water heaterskeyboard_arrow_right

Discover the innovative design features A. O. Smith engineers use to keep your water heater both functional and safe.

Learn more about water heater safetykeyboard_arrow_right
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Contractor Resources

  • Screwdriver and wrench icon.

    Installation Guide

    Download our gas tank water heater installation instructions.

    View Document
  • Set square icon.

    Resource Guide

    Match the flow rate to your customer's needs.

    View Document
  • Overlapping arrows icon.

    Cross-Reference Tool

    Search for NAECA-compliant replacement options.

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