Short vs Tall Water Heater

Last Updated On June 11, 2024

Updated on June 8, 2022



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short vs tall water heater

Are you in the market for a new water heater and debating between a short or tall water heater?

Whether you have moved to a new house or need to replace an existing residential water heater before it fails, it is important to understand the difference between short and tall water heaters.

In this PlumbingNav guide, we will cover:

  • Differences and similarities between short and tall water heaters
  • Factors to consider when making your choice
  • Determining if you have a short or tall water heater
  • How short and tall water heaters work
  • Accessories for short and tall water heaters

What's In This Guide?

      Difference Between Short vs Tall Water Heaters

      The main difference between short and tall water heaters is the tank size and gallon capacity.

      Tall Water Heater

      A tall water heater is casually referred to among water heater experts as the “tall boy.” Typically, they have a height that ranges between 46 and 76 inches. They are cylindrical in shape with a diameter of 18 to 21 inches, and their water capacity ranges between 30 and 100 gallons.

      Since they are significantly taller, they require ample space for the installation of the tall heater and the plumbing pipes connected to the house. They are commonly installed in the garage or basement, where their height is easily accommodated.

      The plumbing pipes are about 40 inches tall. If your basement or garage space is slightly less than needed to accommodate both the pipes and the heater, you can install the pipes diagonally to fit.

      However, the unit itself and the main water supply pipe attached on top of the heater has to be mounted in an upright position. A vertical alignment also provides optimal water flow and decreases the risk of leaks and clogging.

      Short Water Heater

      On the other hand, the short water heaters, commonly referred to as the “low boys,” are wide and short. They are about 30-49 inches tall with a diameter range of 20-26 inches. They have a water capacity of 20 to 50 gallons.

      Due to their comparatively smaller size, they can be installed in smaller and crowded spaces such as crawl spaces or attics. The connecting pipes for short water heaters are usually 29 to 32 inches tall. These smaller units can also work well for off-grid water heating.

      Similarities Between Short and Tall Water Heaters

      Apart from the height, diameter, and size of their plumbing pipes, short and tall water heaters have a similar operating mechanism. Conventionally, they are tank water heaters as opposed to tankless. While some heat using electricity, others use natural gas or liquid propane.

      In some cases, a short or tall water heater can serve as a reservoir for hot water heated either by a solar water heater or heat pump water heater (hybrid water heater).

      Both can either be installed inside the house or in auxiliary spaces. Ideally, whether you choose a short or tall water heater, it should be installed close to the entire house’s plumbing system.

      Any storage water heater will risk corrosion, so they come with an anode rod to help protect the tank. They also must remove sediment buildup regularly, requiring regular flushing of the storage tank water heater. It’s important to select the right anode rod by water type.

      Factors to Consider When Choosing Between a Tall and Short Water Heater

      When choosing between a short and tall water heater, the main factors to consider are how much space you have for installation, your capacity needs, and your preference.

      Measuring Your Installation Site

      Before going on the market to buy a short or tall water heater, the first step is to determine what dimensions you are working with. Determine the installation site and, with a tape measure, take the height of the space where the heater and plumbing pipes would be installed.

      Then, measure the width of the space to determine the diameter to abide by. Note whether there is any space left on the top and sides to allow room for easy access, proper ventilation, and pressure release.

      Compare the measurements you get against the standard range of dimensions for tall vs short water heaters to determine which one is best suited for you. If you are not sure about which type of water heater to install, consult with a professional plumber.

      The site you choose should be dry with no water leakage on the surrounding surfaces as these could lead to the water heater rusting and breaking down earlier than its expected life span. Also, there should be 30-40 inches allowance between the heater and the surface on top for ventilation and maintenance.


      Tall water heaters are ideal if you have a high output of hot water. For instance, in a home with more than three members and where the heater will be supplying water to many fixtures at a time, a taller water heater would be ideal. 

      On the other hand, short water heaters work best if your demand for hot water volume is low, for instance, in a studio apartment, where a 30 or 40 gallon tank can support the home’s needs.

      Energy Bills

      Whether you have an electric heater, power vent, gas, or propane water heater, energy consumption is higher for taller water heaters as they have a higher power rating. 

      Short water heaters are generally more energy-efficient as they have a lower power rating.

      They also heat the cold water faster and recover than tall ones due to the lower water volume in the storage tank. This is important when trying to save money.

      How to Determine Whether Your Water Heater Is Short or Tall

      If you already have a water heater and do not know whether it is short or tall, you can determine it by checking the heater’s specifications or measuring. If checking the specifications, look for the serial number label on the heater and check if it has the capacity indicated.

      If you have the product’s manual, check the product dimensions that are provided therein. Otherwise, take the width (diameter) and height dimension measurements using a tape measure.

      How Do Short and Tall Tank Water Heaters Work?

      Whether your water heater is short or tall, the operating mechanism is the same. In a nutshell, the contemporary tank water heater has a tank, motor, and heating mechanism.

      The tank holds water while the motor gets heated either using gas or electricity, and the heat is transmitted to the water in the storage tank.

      The storage tank holds the heated water until there is a need to use it, then it is let out through a valve into the pipes and out through the open hot water fixture(s). The water heater tank’s indicated capacity is the maximum amount of water the storage tank can hold.

      How to Tell if Your Water Heater Is Powered by Gas or Electricity

      It is simple, and you can do it yourself. However, before you start, ensure that the heater is powered off to prevent burning accidents. Open the access panel. It is usually located on the side of the heater. 

      If you see gas pipes, then the heater is gas or propane powered; otherwise, it is electric powered if you see heating elements.

      An electric water heater uses up to two replaceable heating elements. They are less expensive, highly efficient, and have a capacity of 30 to 100 gallons and above. Gas water heaters use a burner; therefore, they have an open flame when heating.

      A gas water heater needs enough ventilation room to prevent overheating and should not be installed near flammable materials or items. They are more expensive upfront but use less energy in the long run compared to an electric water heater.

      Which Is Better: Short vs Tall

      Generally, a tall water heater is the best option if:

      • Your hot water runs out frequently
      • The volume of hot water flowing out is considerably low with several open fixtures
      • You use hot water in your washer or dishwasher
      • Your home hosts more than three people
      • You have ample space for installing both the unit and plumbing pipes while leaving enough space on top and the sides for accessibility and ventilation.
      • You do not mind a higher energy bill in order to store more hot water

      Conversely, a short water heater is the best option if:

      • You have a lower demand for hot water
      • You live in a small house, and you have limited installation space
      • Your home has less than three occupants
      • You are keen to save up on energy bills

      FAQs for Short vs. Tall Water Heater

      Is a short or tall water heater better?

      Tall water heaters work better if you have higher hot water demands, and short water heaters work best if you have space constraints. 

      What is the difference between a tall and short hot water heater?

      Tall water heaters usually provide more hot water for larger homes, when short water heaters work best for households of only 2 – 3 people. 

      How tall is a standard water heater?

      Tall water heaters reach up to 76 inches, and short water heaters top out at 49 inches. 

      How do I know what size water heater I need?

      Measure the space you plan to put the water heater, considering ventilation equipment on top and how easy it will be for you to change out the anode rod.

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      About Plumbing Navigator

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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