How to Choose a Water Heater

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hot water tank

So, you’re looking to replace your water heater. Whether you don’t know where to start looking or you already have something in mind, this guide will help you choose the right unit for your home. We’ll go over the main types of water heaters available, the new energy efficiency guidelines, how to calculate your household’s water needs, and installation tips.

Types of Water Heaters

As you probably already know, the type of unit that you go for doesn’t just affect your bill; it also affects your family’s comfort. A unit that provides too few gallons of water per minute means that you can’t shower and run the dishwasher at the same time, while an oversized tank will actually waste energy. Here are three of the most basic unit types that you should know about.

Storage Tank Water Heater

This is the most common type of water heater found in residential households. Just as the name suggests, it consists of an insulated tank that heats and stores water. Keep in mind that:

  • It’s compatible with electric, propane, gas, and oil energy sources.
  • On average, most storage tank water heaters last for 10 to 15 years.
  • It works well for households that use multiple water sources at the same time.
  • Natural gas water heaters tend to cost more upfront than electric-powered units, but they also cost about half as much to run.
  • Storage tank water heaters are susceptible to standby heat loss, aka wasted energy.
  • When shopping for a storage tank, you should look for a thermal resistance of R-12 to R-25.

Tankless Water Heater

tankless water heater

ATMOR 900 Series Tankless Electric Instant Water Heaters SKU: 15076129

Also known as an on-demand water heater, this type of unit uses coils to heat water as you need it. When shopping for a tankless water heater, remember that:

  • It’s compatible with electric, propane, and gas energy sources.
  • It lasts 20 years on average, and replacing its parts will extend its life by a few more years.
  • Compared to storage tanks, a tankless water heater provides a more limited amount of water — 2 to 5 gallons — per minute, which may not work well for larger families.
  • It’s possible to install two water heaters or a booster unit, which negates the previous problem.
  • Homes with natural gas get a better flow rate than those powered by electricity.
  • Tankless water heaters are more energy-efficient than storage tank water heaters.
  • There aren’t any standby heat losses, but some units have a pilot light that sucks up energy.

Heat Pump Water Heater

Also known as a hybrid water heater, this type of unit takes warm air, steals its heat, and transfers it to your household water supply. It may come with its own built-in storage tank, or you can set it up to work with an existing storage tank. You should also know that:

  • It’s compatible with electric, gas, and geothermal energy sources.
  • It uses 60 percent less energy than standard electric water heaters.
  • The upfront cost is higher than that for a tankless or storage tank water heater.
  • It works better in warm climates — of at least 40 to 90 degrees — than it does in colder climates.

These are just a few of the options available. There are other options that have higher upfront costs with long-term savings, such as solar power water heaters, condensing water heaters, and integrated units. Integrated units, such as indirect water heaters, are a popular way to lower energy costs.

Understanding the New Guidelines

Oh, no. A bunch of boring information about government guidelines? Don’t worry, we won’t go into the nitty-gritty details. All you need to know is that the Department of Energy Standards changed its guidelines on April 16, 2015, which forced manufacturers to create more energy-efficient products. This actually helps homeowners.

Does it affect you personally? If you have a storage tank water heater that runs on electricity, oil, or gas, then it probably does. On average, units that are 55 gallons or smaller are now 4 percent more efficient than their predecessors. Tanks that hold more than 55 gallons are even more efficient, with heat pumps saving at least 50 percent and condensing gas units saving about 25 percent on energy bills.

The newer tanks are also larger by at least 1 to 2 inches. If your current unit is already crammed into an impossibly tight space, you’ll definitely need to put your new water heater in a different spot.

Calculating Your Water Usage

reading water tank meter

Okay, so you’ve got a general idea of the types of water heaters on the market, and maybe you’ve decided what you want. But how big of a tank do you need, or how many tankless units should you have installed? To determine what capacity you need, you should calculate your household’s water usage.

If you’re going for a storage tank, you’ll need to know the first-hour rating, which is how much hot water the tank delivers in one hour. To decide what FHR you need, you must estimate the peak hour demand: the time of day your household uses the most water, how many members use it, and so on. If you’re going for a tankless unit, you’ll be looking at the gallons-per-minute rating. To know what GPM you need, you’ll have to calculate your household’s flow rate and temperature rise.

It’s more complicated to calculate capacity and energy savings for other water heaters. You should contact a qualified contractor to get the most accurate estimate.

Installation Tips

plumber fixing water heater

Unless you’re lucky enough to have a family member or friend who works in the trade, you’ll need to choose a professional installer. When you’re making such an important investment, you want to make sure the job is done right.

You’ll also need to decide where the new unit is going. It may have different dimensions than your current water heater and need to go in a different room. If you’re switching to a different type of unit, there may be other considerations. For example, you may need to install an integrated unit next to the boiler or furnace.

With a bit of research and planning ahead, you’re sure to find the water heater that works best for you.


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Jill Canty

hiker; runner; breakfast food, mcdonalds, and beer lover; HBO and AMC marathoner; insatiable modern fiction devourer; hopeful globe-trotter; concert-goer; proportionate Beyoncé obsession-haver; and - of course - content writer.