Water Tank Heaters: A Comprehensive Buying Guide

Explore the most popular home water heating products with our comprehensive buying guide to gas and electric water tank heaters.

Find everything you need for proper tank selection, including the best models, popular 50-gal options, selecting and sizing tips, installation, cleaning and maintenance advice, and troubleshooting help.

Check out our guide to learn more and choose the perfect water heater for your home.

Water tank heater
Water tank heater (photo: hotwatertalk.com)

Water tank heaters, also known as hot water tanks, stand-alone and conventional water heaters, are very popular in North America.

If you live in a condo, you may be renting a 40- or 50-gallon tank-type unit from companies, like I do from Reliance. Alternatively, you can purchase one for several hundred to a few thousand dollars depending on the features, such as condensing gas or electric heat pumps.

If you’re unsure whether to rent or buy, read our article to compare the pros and cons.

What Is a Water Tank Heater?

Water tank heaters are essential household and commercial appliances designed to heat and store hot water for various uses, including bathing, cooking, cleaning, and space heating.

These popular devices consist of an insulated tank that holds water, which is heated by electric elements or gas burners until it reaches a predetermined temperature.

The heated water is then stored in the tank, ready for use, ensuring a constant supply of hot water when needed.

Water tank heaters come in various capacities and sizes, catering to the needs of different households and commercial establishments.

Their primary function is to provide a reliable and convenient source of hot water, enhancing comfort and hygiene in daily life.

Water Tank Heater Types

Homeowners have the option to choose from the three most popular types of hot water tanks: gas, electric, and solar-powered. Each type has its own advantages and disadvantages, and the choice depends on factors such as energy efficiency, cost, and environmental impact.

Gas Water Heaters

Gas water heaters utilize natural gas or propane to heat water. They have a gas burner at the bottom of the tank with a chimney running up through the center of the tank to vent exhaust gases outside.

How they work: When the water temperature in the tank drops below a certain point, the gas burner ignites to heat the water. The heat is transferred to the water in the tank, raising its temperature. Exhaust gases produced during combustion are vented out through a flue.

Pros and cons: Gas water heaters typically have lower operating costs because gas is cheaper than electricity in many areas. They also heat water faster than electric models. However, they require proper venting to the outdoors, have a higher initial cost, and pose a slight risk of gas leaks or carbon monoxide exposure if not properly maintained.

According to Union Gas (Canada), homeowners can save between $300 and $400 annually (based on 2016 data) compared to electric models. However, actual savings depend on fuel rates and the specific models being compared.

Electric Water Heaters

Electric water heaters are appliances that use electrical resistance elements to heat water. These elements are submerged inside the water tank, and when electricity passes through them, they heat up and transfer the heat to the surrounding water. This type is widely used due to its simplicity and the widespread availability of electricity.

How they work: Electric water heaters heat water using one or more electric resistance elements that are turned on and off by a thermostat based on the water temperature in the tank. As water heats to the desired temperature, it remains in the tank until needed.

Pros and cons: The advantages of electric water heaters include their ease of installation, the absence of a need for venting, and generally lower initial costs compared to other types. However, they can be more expensive to operate due to the higher cost of electricity compared to gas and might not work during power outages.

Solar Water Heaters

Solar water heaters use the sun’s energy to heat water, making them an environmentally friendly option. They typically consist of solar collectors installed on the roof and a storage tank.

How they work: Solar collectors absorb sunlight, converting it into heat. A fluid circulates through the collectors, transferring the heat to water in a storage tank. On cloudy days, a backup system (usually electric or gas) ensures a continuous hot water supply.

Pros and cons: The major advantage of solar water heaters is their potential to significantly reduce energy bills, as they rely on the free and renewable energy of the sun. They also reduce carbon footprint. However, the initial setup and installation costs can be high, and their efficiency is weather-dependent, requiring a backup system for less sunny days.

Heat Pump Water Heaters

Heat pump water heaters, also known as hybrid water heaters, use electricity not to generate heat directly but to move heat from one place to another, making them more energy-efficient than traditional electric heaters.

How they work: These systems pull heat from the surrounding air or ground to heat the water. A heat pump on top of the water tank moves heat from the air outside or inside the room to the water in the tank. This process is much more energy-efficient compared to generating heat directly.

Pros and cons: Heat pump water heaters have a much lower operating cost and are more energy-efficient than conventional electric and gas water heaters, reducing energy use by up to 60%.

However, they have higher initial purchase and installation costs, require a larger space for optimal operation, and their efficiency can be affected by the ambient temperature of the location they are installed in.

How Much Does a Water Tank Heater Cost?

The Home Depot provides useful information on the cost of water heaters.

For a 50-gallon gas water heater, the price range is between $500 for basic models with a 6-year warranty and $1400 for advanced models with a 12-year warranty, power venting, ultra-low NOx emissions, and high-quality components.

In contrast, electric water heaters are generally cheaper, with standard models ranging from $400 to $900, depending on the warranty and element quality. Hybrid electric models can be more expensive, costing up to $2000.

Sizing Tips – Choosing the Right Capacity

Determine Water Tank Capacity

Choosing the right tank capacity is crucial to ensure that you have enough hot water for your household’s needs.

The first step is to determine how many gallons of hot water you typically use during peak demand, which is when multiple hot water appliances or faucets are in use simultaneously. This can be calculated by adding up the flow rates (in gallons per minute) of all the hot water fixtures you use at the same time, and multiplying that by the duration of use.

To determine the appropriate water heater capacity, you should consider the size of your household, the number of bathrooms, and your typical hot water usage. As a general guideline, allow for 10-15 gallons of tank capacity per person in the household. Nonetheless, larger tanks may be necessary if you have larger bathtubs or Jacuzzis.

The capacity of tank-type heaters ranges from 20 to 100 gallons, with the most popular sizes being 40, 50, 60, and 80-gallon tanks, which produce enough hot water for families of 4-6.

Consider the First Hour Rating

It is also important to consider the First Hour Rating (FHR) and recovery rating of the water heater. FHR is the amount of hot water the unit can produce in the first hour of use, while recovery rating refers to how quickly the unit can heat a full tank of water after it has been depleted. The FHR should match your peak demand times, and a higher recovery rating means you will have more hot water available for use during those times.

If you have limited space or want to save on energy costs, you may want to consider a tankless water heater.

Additionally, small-sized hot water tanks of only a few gallons like the Ariston from Bosch or SHC Mini-Tank from Stiebel Eltron are available for point-of-use applications, and these are typically installed near the faucet or shower.

How to Select a Water Tank Heater and What You Should Know

Life Expectancy and Warranty

“When is the best time to replace a water heater?” – many homeowners will ask.

According to experts, the average lifespan of water tank heaters is 13 years, while tankless heaters have a longer lifespan of over 20 years. Most water heaters available today come with a 6-year warranty, while higher quality models equipped with one or more commercial-grade anodes may come with a 12-year warranty.

For tankless models, warranties can extend up to 15 years, making them a reliable and long-lasting option. However, it’s important to keep in mind that the lifespan of a water heater can be affected by factors such as water quality, maintenance, and usage.

As a general guideline, it’s recommended to consider replacing a water heater that is over 10 years old, even if it appears to be functioning properly. This can help prevent sudden failures or leaks that could cause water damage to your home. Additionally, if you notice signs of rust, corrosion, or leaks, it’s important to have a professional assess the unit and determine if it needs to be replaced.


Choosing the right tank size is crucial to meet the demand at peak time.

Selecting an oversized water heater can lead to increased energy costs as the unit will heat up more water than is actually needed. This means that you will be paying for more energy than necessary to heat the water.

Additionally, an oversized water heater may take up more space than is necessary, which can be a problem if you have limited space in your home.

Selecting an undersized water heater tank can lead to insufficient hot water supply during peak demand, such as when multiple appliances or faucets are in use simultaneously.

This can result in discomfort or inconvenience for household members.

Additionally, an undersized water heater may be overworked, leading to a shorter lifespan and potentially higher maintenance costs.

For more information, refer to a sizing guide or talk to a plumber or HVAC technician for advice.

First Hour Rate

The hot water delivery capability, or first-hour rate, of your water heater is essential to ensure you have enough hot water when you need it most. It’s determined by the tank capacity and recovery rate, and indicates how much hot water the unit can produce in one hour. This is especially important during peak demand times.

Recovery Rate

The recovery rate of a water heater indicates how much hot water it can produce within a specific time frame. A model with a higher number of BTU or Watts will typically have a faster recovery rate than a lower-rated one.

When choosing a water heater, it’s important to consider your household’s demand for hot water. The greater the demand, the higher the required recovery rate to ensure that you have enough hot water when you need it.


High-efficiency water heaters may come with a higher upfront cost, but they pay off more quickly in terms of energy savings. In addition, they typically offer better quality, efficiency, and warranties, while also being more environmentally friendly.

These models often feature thicker insulation, more efficient heat exchangers, factory-installed heat traps, improved gas burners, and venting. The efficiency of gas, propane, and oil-fired water heaters is measured by a uniform energy factor (UEF), with higher numbers indicating better efficiency.

Available Features

The capacity, first-hour rate, recovery rate, and energy efficiency are the most important factors to consider when selecting the best water tank heater for home use.

However, you may also want to consider available features. These include advanced systems such as self-cleaning and diagnostic systems, as well as intelligent gas control valves.

Other features to consider include LED displays, hot surface ignition, flue dampers, power or direct venting, the number of anodes, and the quality of materials used.

Benefits of Water Tank Heaters

  • Simple and proven design: Traditional tank water heaters have been used for decades, and their design is well-known and widely used. They consist of a tank that holds a certain amount of hot water and a heating element or gas burner that keeps the water at the desired temperature. This simple design has been proven to be reliable and effective.
  • Less demanding: Tank-type models are less demanding than tankless. They don’t require special installation or ventilation, and they don’t need to be flushed or descaled regularly. They are also easier to repair, with most parts readily available at local hardware stores.
  • Cheaper: Traditional tank heaters are generally less expensive than tankless units. They are also easier to install, which can save on installation costs.
  • High efficient: While tank water heaters are not as energy-efficient as tankless models, many high-efficiency models are available that are Energy Star certified. These models can help reduce energy costs and save money over time.
  • Condensing models available: Some models are designed to be more efficient by using a condensing system that captures and reuses heat that would otherwise be lost. These models are more expensive, but they can be more efficient and cost-effective over time.
  • Various capacities available: They come in a wide range of sizes, from small units that can be used under a sink or in a tiny home to large units that can serve a large family or commercial property.
  • Several types (size) available: In addition to different capacities, tank water heaters also come in different shapes and sizes to fit different spaces and meet different needs. Tall models are common in homes, while short and lowboy models are ideal for basements or crawl spaces with low ceilings.
  • No minimum water flow is required: They are versatile and can be used for a wide range of applications, from small apartments to large commercial buildings. They don’t require a minimum flow rate, so they can work well for low-demand applications as well.
  • If you have a gas-powered water heater, hot water is available even during the power outages: Tank water heaters that are powered by gas can still provide hot water during a power outage, which can be important in areas with frequent power outages or natural disasters.
  • Smaller gas requirements: Traditional heaters require less gas than tankless models, which can make them more cost-effective in areas with high gas prices.
  • Easily adapted for use in solar water heating: They can be easily adapted for use with solar water heating systems, which can further reduce energy costs and increase efficiency.
  • Great for smaller families: They are often a good choice for smaller families or households with lower hot water demands, as they can be less expensive and more practical than tankless models.


  • Increased utility bills since a water heater is heating water even if there is no demand.
  • Lower efficiency
  • Larger footprint
  • Limited hot water capacity
  • Shorter warranty
  • Short lifetime
  • Requires regular cleaning due to the sediment buildup issue (in hard water areas).

How Does a Water Tank Heater Work?

Conventional water tank heaters offer a simple yet effective design that allows for easy floor installation, with the tank usually positioned vertically.

The main component is the water storage tank, which is typically made of metal, where hot water is stored and later used for daily activities such as showering, bathing, dishwashing, or laundry.

To improve heat retention, the metal tank is covered with foam insulation, usually with a thickness of 1 to 3 inches and a different R-value (higher R-value, better insulation).

Cold water enters the storage tank from the bottom through a dip tube, also known as the cold water inlet.

Once heated by the gas burner or electric heating elements, the hot water rises to the upper section of the tank and flows through the hot water outlet to an open tap. At the same time, cold water replaces the hot water, which ensures a constant supply of hot water is available.

This process repeats until the water temperature reaches the set value on the thermostat. If the temperature falls below the set value, the water heater runs again to heat the water.

Some models incorporate innovative technology, such as sensors, flow valves, electronics, and electrodes, to provide better performance, greater efficiency, and comfort.

Hot water tanks are generally safe to use. They use anode rods and glass lining for corrosion protection, a drain valve for draining and flushing, and a TPR valve to prevent extreme temperature and pressure buildup.

The main components found in electric and gas water heaters are explained in this article.

Despite their simple design, tank water heaters still require proper installation, maintenance, and troubleshooting. It is recommended to contact the plumbing expert for assistance.


Here is the list of the popular brands/manufacturers of HVAC equipment in North America, including water tank heaters:

  • American
  • AO Smith
  • Bradford White
  • GE or General Electric
  • John Wood
  • Marathon
  • Whirlpool
  • Reliance
  • Rheem
  • Ruud
  • Richmond
  • State
  • US Craftmaster

Tips to Save Money

Get a High Efficiency Model

If you have an old tank-type water heater, it’s recommended to replace it with a more energy-efficient model to save on utility bills in the long run.

Consider looking for condensing models like the Vertex from AO Smith or Polaris, which have higher efficiency. Also, consider getting a model that is solar-friendly to further reduce energy costs.

Install an Insulation Blanket

Want to check if your tank water heater is wasting energy?

Try this simple test: place your hand on the outside surface of the tank. If it feels warm, your unit likely needs better insulation.

Adding an insulation blanket or “jacket” can reduce standby heat loss and increase your savings, just like with energy-efficient units that come with thicker foam insulation.

If you’re in the market for a new unit, look for one with a higher insulation value. R-24 is considered the best insulation value, and will help ensure that your water heater operates as efficiently as possible.

Insulate Pipes

There is a lot of heat and energy wasted when waiting for hot water to reach the tap. Insulate all the pipes, especially sections going through the unheated areas, and you will reduce the energy loss.

Lower the Temperature

One way to save energy with your water heater is to lower the thermostat temperature by a few degrees.

For every one-degree reduction, you can save one percent of energy consumption over eight hours. The recommended temperature range is between 120 and 140 degrees Fahrenheit, although some factory settings may be lower, between 120 and 125 F.

Keep in mind that lowering the temperature too much may affect hot water availability and potentially cause bacterial growth. It’s best to consult with a professional plumber to determine the optimal temperature setting for your water usage needs.

Common Water Tank Heater Problems

There are several reasons why you may not have hot water in your home from your water heater.

The most common issues of gas water heaters,  are pilot light and thermostat failure.

On the other hand, for electric water heaters, the problem may be caused by malfunctioning heating elements or thermostats.

There are also some common problems that can occur in both types of water heaters, including:

  • Leaking (from the top or bottom)
  • Noise
  • Rotten egg smell
  • Water is not hot enough or is too hot
  • Discolored water

While many of these issues can be resolved with DIY repairs, it is always important to prioritize safety and caution. If you are not comfortable troubleshooting and fixing the problem on your own, it is recommended that you call a professional for assistance.

Are Water Tank Heaters Worth the Investment?

Water tank heaters are a reliable and traditional choice for households with moderate hot water needs, offering a straightforward solution compared to the on-demand heating of tankless systems.

Despite their reputation for lower efficiency, recent advancements have introduced high-efficiency models with over 90% ratings, such as the Polaris and AO Smith Vertex for gas, and Rheem and AO Smith for electric hybrids.

These improvements have made water tank heaters more appealing by enhancing energy savings and performance.

When comparing them to tankless options, it’s important to consider factors like energy efficiency, capacity, and initial cost.

For those matching the heater to their specific needs, water tank heaters can be a worthwhile investment, balancing proven technology with modern efficiency gains.


Can a Water Tank Heater Be Repaired?

Yes, a water heater tank can be repaired in some cases, but it depends on the extent and location of the damage. Small leaks or cracks in the tank can sometimes be repaired with sealant or a patch kit, but larger or more significant damage may require the replacement of the tank or the entire water heater. It’s best to have a professional plumber inspect the damage and advise on the best course of action. It’s also worth noting that the age and condition of the water heater may also impact whether repair is a feasible option. In some cases, it may be more cost-effective to replace the unit altogether.

Can Water Heaters Explode?

While it is rare for water heaters to explode, it is possible under certain circumstances. The most common cause of water heater explosions is a buildup of pressure inside the tank, which can occur if the temperature and pressure relief valve malfunctions, the thermostat is set too high, or there is a blockage in the pipes leading to and from the tank. This buildup of pressure can cause the tank to rupture, resulting in an explosion.
To minimize the risk of a water heater explosion, it’s important to have the unit inspected and maintained regularly by a licensed professional.

Can Water Heaters Work Without Electricity?

Electric water heaters need electricity to function and heat the water. Gas water heaters can work without electricity, but they may not operate efficiently, and other parts of the plumbing system may require electricity. Have backup power options available in case of an emergency.

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