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The Perfect Fit: Matching Tank Sizes to Household Needs

Is it about time to replace your water heater? Are you moving into a new home and trying to decide what type of water heater to get? 

One of the things you’ll have to consider is which of the various water heater sizes available is the best for you. You can do that by matching your usage habits to tank sizes.

Before you do that, though, you’ll need to choose between a conventional tank system and a tankless water heater. Tankless systems are relatively new and have their benefits, but the vast majority of homes still use tank systems. There are several reasons for this:

  • Hot water tanks are much more budget-friendly because they’re less expensive both to purchase and install. In fact, a tankless system can cost twice as much to buy and install.
  • There’s less maintenance with a hot water tank, and when repairs are necessary, they’re less complicated to perform, so they’re less expensive. The best maintenance plan is to learn to spot obvious signs of trouble and also to have professional servicing performed at least once a year.
  • A wide range of water heater sizes is available, so you can get the right size tank for your household needs. This makes it less likely that you’ll run out of hot water when you need it. It also means you won’t be paying to heat water you’re not using.
  • Hot water tanks are always running in order to keep hot water available on demand. There’s typically less waiting time for hot water with a tank versus a tankless system.

Natural Gas or Electric?

Before you determine the tank size that you’ll need, you have to choose whether you want a water heater powered by natural gas or by electricity. There are also some hybrid models on the market that use both sources to heat water.

In some places, the choice will be simple – you won’t have a choice! When you do have the option to choose between natural gas and electric, however, you might want a natural gas water heater because of the following benefits they have over electric-powered water heaters:

  • Faster recovery: Natural gas heats water twice as fast as electricity does. Because of that, you have less waiting time for cold water to heat up. It also means you might be able to go with a smaller tank, which saves space and money.
  • Cheaper to operate: Energy costs do fluctuate. However, natural gas is typically cheaper than electricity, so you’ll probably have lower energy bills.
  • More compact: Natural gas water heaters have a more compact design than electric water heaters. Since water heater tanks take up significant space, this can be a big deal, especially in small homes and homes without basements.

Determining the Right Tank Size

Common water heater sizes are 30-, 40-, 50-, and 75-gallon tanks. One way to determine the right size is to look at how many people are in a household and what the level of demand for hot water is. Four Seasons is here to help you determine what water heater size is best for your home. The following are some general guidelines based on family sizes:

  • 1-2 people with a regular or low demand for hot water can typically get by with a 30-gallon water heater. If, however, their usage is high, then 40 gallons is a better option.
  • A family of 2-3 with regular or low demand probably needs a 40-gallon tank, but for high demand, they should go with 50 gallons.
  • For a family of 3-4 that has regular or low usage, 40 gallons should be fine, but high demand will require 50 gallons, or possibly 75.
  • Families with 5+ members will want at least a 50-gallon water heater. If hot water usage is high, then 75 gallons is definitely the recommended option. On a busy morning, no one wants to run out of hot water for showering, washing dishes, etc.

A more precise way to choose among water heater sizes is to figure out what your home’s first-hour rating is. The first-hour rating is the amount of hot water needed during the hour of peak hot water usage, and it tells you how much hot water the tank can deliver in that hour. 

Also included in the first-hour rating is the recovery rate. This rate comes from the combination of how much hot water the tank can store and how quickly the tank can heat cold water to the desired temperature when you have to replenish it.

The following are some common uses for hot water and a general range of how much hot water they require. After figuring out what your peak hour of hot water usage is (for most, it’s a period during the morning, but that doesn’t hold for every household), determine which activities the water heater serves during that period. Once you do that, then you can add up the estimated gallons needed to determine the right water heater size for your home.

  • Washing clothes– 25 to 40 gallons per load
  • Bath– 15 to 25 gallons
  • Housecleaning– 5 to 12 gallons
  • Washing dishes in a dishwasher– 5 to 10 gallons per load
  • Shampooing– 5 gallons
  • Food prep– 3 to 6 gallons
  • Washing dishes by hand– 3 to 4 gallons. Note that this is for hot water only. You’ll use even more water for the rinsing, which most people do with cold water.
  • Showering– 3 gallons per minute
  • Shaving– 2 to 3 ½ gallons
  • Bathing a baby– 2 gallons
  • Washing hands– 1 to 2 gallons

Let’s say that during the peak hour, a family of 3 showers for an average of 8 minutes each. They also run a dishwasher load. One person shaves at a sink, and another uses hot water to help prepare breakfast.

That’s up to 91 gallons needed. This family needs a 75-gallon tank or larger. They might also want to consider shorter showers or running the dishwasher later!

Read more on What Should You Look For When Buying Water Heaters?


In summary, selecting the ideal water heater size for your home requires careful consideration of various factors, including your household size, hot water usage, and energy preferences. This decision can be complex, but you don’t have to navigate it alone. Four Seasons Plumbing is here to guide you through every step of the process. 

Our experts will help you assess your specific needs, calculate your home’s first-hour rating, and recommend the most efficient and cost-effective water heater for your situation. With our professional insight and installation services, you can ensure that your water heater not only meets your daily demands but also enhances your home’s energy efficiency and comfort. Trust Four Seasons Plumbing to bring the warmth and convenience of the perfect water heater into your home.

Max Rose - Owner of Four Seasons Plumbing


Max Rose

Max Rose is the owner of Four Seasons Plumbing, a plumbing company in Asheville, North Carolina.