Whether you’re installing a new water heater or thinking about upgrading your existing unit, chances are you’ve wondered about choosing the right size water heater for your home. Do you go bigger to avoid running out of hot water? Smaller for better efficiency?

There’s no one-size-fits-all answer to the question of water heater size. Proper water heater sizing depends entirely upon

  • how many people are in your home
  • how much hot water you typically use
  • how many hot water fixtures are in your home

Here, we’ll walk you through the steps to determine the right size water heater for your home, your budget, and your family’s needs.

Why Water Heater Size Matters

Adequate Supply

If you choose a water heater that’s too small, you might never have enough hot water. And no one likes running out of hot water halfway through a shower.

A Long Lifespan

Or you may end up totally overworking the unit, meaning you’ll have to deal with frequent repairs and/or premature breakdown. Water heaters are a sizable investment, and you probably don’t want to replace yours any sooner than expected. (Many tank water heaters can be expected to have a lifespan of 8-10 years when properly maintained.)

Lower Energy Bills

A water heater that’s too large may result in unnecessarily high energy bills. With an oversized unit, you’ll be paying to heat water you never even use. It’s a tax on the environment and on your bank account. Choosing just the right size water heater will save you money month after month, year after year.

For our ultimate guide to water heaters, check out this blog post: Here’s Everything You Need to Know About Your Water Heater.

The Very General Guide to Water Heater Sizing

If you’re looking for detailed, usage-specific guidelines on how to choose the right size water heater for your home, keep reading. But if you want a quick cheat-sheet guide, here’s what is generally recommended. Again, these figures are estimates, so take them with a grain of salt:

  • For 1 to 2 people, consider 30-40 gallons
  • For 2 to 3 people, consider 40-50 gallons
  • For 3 to 4 people, consider 50-60 gallons
  • For 5+ people, consider 60-80 gallons

The Detailed, Step-by-Step Guide to Water Heater Sizing

If you want to maximize efficiency and get the most out of your budget, you’ll want to choose the right size water heater for your home. To do that accurately, you’ll need to measure how many gallons of water you typically use when the demands on your hot water heater are highest.

  1. Identify Your Peak Hour
    Consider a typical day in your home. Which hour is your busiest hot water-using hour? Is it the hour on a weekday morning when your family showers before school and work? Or on a Saturday night when you’re running multiple loads of laundry and/or dishes?

    Whatever that hour is, this is your yardstick for measuring “peak hour demand,” the maximum number of gallons of hot water you’ll need during the busiest hour of your typical day.

    Bear in mind that showers usually require the hottest water of all activities or appliances in your home. So if you have two adults and three kids showering on a Wednesday morning, that’s likely your peak hour.

  2. Calculate Your Peak Hour Demand
    You know when your household uses the hottest water on a typical day. Now, it’s time to calculate how many gallons you usually use in your peak hour. Think of all the hot-water activities that ordinarily go on during this hour. Now, do the math using the table below as a guide. This will help you accurately estimate your peak hour demand.

    For instance, let’s say within the span of one hour on a typical morning, your water heater is supplying hot water for

    • 4 showers
    • 1 shave
    • 1 hand dishwashing session

    This amounts to a total peak hour demand of 46 gallons.

    Are you tired of waiting on hot water? Discover how to get instant hot water, reduce waste, and save money here in this blog post.

  3. Compare Your Peak Hour Demand with a Unit’s First Hour Rating
    Once you’ve calculated your peak hour demand, you’ll be able to determine the right size water heater for your home. To do this, choose a water heater with a first-hour rating (FHR) within one or two gallons of your peak hour demand.

    All water heaters have an FHR which indicates the number of gallons of hot water a given unit can provide in one hour when starting with a full tank of water.

    You can find your water heater’s FHR in the top left corner of the yellow EnergyGuide label, like the one on the tank shown below.

    Ideally, if your FHR and peak hour demand match—or are within one to two gallons of one another—you’ll get optimum supply and demand; your water heater will be able to provide enough hot water for your home’s needs.

  4. Consider the Number of Fixtures in Your Home
    One other important factor to consider when choosing your water heater is the number of fixtures in your home that use hot water. These include your dishwasher, kitchen and bathroom faucets, washing machine, showerheads, and bathtub faucets. If you regularly use multiple hot water fixtures at once, you may need a bigger tank. Otherwise, your water heater may not be able to provide adequate hot water to your washing machine and two showers simultaneously.

To Sum It Up
Remember, choosing the right size water heater for your home all comes down to hot water usage. While one family of four could do just fine with a 30-gallon tank, another may require a unit twice that size. It’s worth taking the time to accurately assess your hot water needs. It’ll save you money in the long run!

Again, here are the four steps to choosing a water heater that’s the right size for your family:

  • Identify your peak hour when hot water is in maximum demand.
  • Calculate your peak hour demand to estimate the number of gallons you’ll need when hot water usage is high.
  • Compare your peak hour demand with the first-hour rating (FHR) of the water heater you choose. The closer those numbers match, the better the fit for your hot water needs!
  • If you’re in need of a new water heater or simply want to trade yours in for one that’s better suited to your family’s hot water usage, contact us today to schedule your service. When you trade in your existing unit, we’ll even give you a $75 discount on the purchase and installation of your new water heater (see below)!

    Schedule Your Service Today!

    At High 5 Plumbing, Heating & Cooling, our trustworthy, reliable experts can help you choose the water heater that’s the right size for your home’s hot water needs. Call us today or contact us online to get your expert estimate—fair and honest every time!

    High 5 Plumbing

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