How to Select the Best Water Tank Heaters: Buying Guide

Gas water heaterWater tank heater

Explore gas and electric water tank heaters - the most popular type of home water heating products. This guide is a comprehensive buying guide where the homeowners can get everything they need for the proper tank selection, including; the best models, popular 50-gal models, selecting and sizing tips, also tips for removing and installing, cleaning, and draining, maintenance and troubleshooting.

If you are looking for the 50-gal gas-powered hot water tank, check out our selection of the top models here, while if electric is your only option, see this review.

ao smith gdhe 50 vertexAO Smith water tank heater - Vertex

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

If you own a condo, you are probably renting one of 40- or 50-gallon tank-type units, as I do from the Reliance company (my Rheem power vent model was part of the deal when I purchased the house), and for a monthly charge ($30).

Alternatively, you can buy one for the price ranging from several hundred dollars for the economy gas or electric models up to a few thousand for the best models that use the most advanced features, such as condensing gas or electric heat pumps.

If you are not sure whether to rent or buy one, read the article to compare, and see the pros and cons.

Water tank heaters: Things to consider

  1. Buying guide - popular models
  2. Types
  3. Sizing tips
  4. Selecting tips
  5. Benefits
  6. Drawbacks
  7. How does a water tank heater work?
  8. Manufacturers
  9. How to save
  10. Common problems

Buying guide

Tank-type water heaters are the most popular type, mainly because of the established market, extensive distributor and service network, reliable operation, and good up-front cost.

Before going into details, and just to have an idea of what other homeowners are searching for, here is the short list of the popular selling models found on amazon.com:

  • Rheem Marathon MR50245 - electric
  • AO Smith Vertex - gas condensing
  • Rheem PROG50 - gas
  • AO Smith GCR 50 - gas

Type selection

Homeowners can choose the following popular types of hot water tanks: gas, electric, and solar powered.

Gas water heaters

John Wood gas water heaterJohn Wood gas water heater

Gas water tank heaters are probably the best option for homeowners who live in areas where natural gas is available.

Propane or LPG is also a good option but is more expensive and requires frequent gas delivery.

In general, gas models are more expensive than electric but they cost less to run and offer more choices with greater flexibility.

The best ones are ultra-high efficient or condensing, including Vertex from AO Smith and Polaris from the American.

According to the Union Gas company (Canada), you can save between $300 and $400 a year (data from 2016) compared to electric, but it depends on the fuel rates and compared models.

Electric water heaters

AO Smith PXNS electric water heaterAO Smith electric water heater

Electric water tank heaters are the most affordable option, available to many homeowners, but cost more to operate. For those looking to get more in return for their investment, electric heat pumps are the way to go, as they can deliver more hot water faster and efficiently than conventional types. Good choices are Rheem Professional and Voltex from AO Smith.

Solar water heaters

Active solar water heaterActive solar water heater

Solar water tank heaters are probably the best choice in southern regions such as Florida due to longer periods of sunny days.

The main advantages are the green technology as they use free and renewable solar energy, making them eligible for government rebates, stimulation, and support.

The alternatives to the above fuel types are oil-fired burners and wood heaters, but these are less popular.

How much does a water tank heater cost?

According to The Home Depot, gas water heaters with 50-gallon tank sizes can cost you between $500 for the atmospheric vented models with a 6-year warranty and $1400 for the ultra-low NOx and power vented models, with the advanced electronics, quality elements, and a 12-year warranty.

Electric water heaters are cheaper; standard models can cost you between $400 and $900, depending on the element quality and a warranty, while hybrids can cost you up to $2000.

Sizing tips - Choosing the right capacity

Before buying a water heater, it is essential to determine how many gallons of hot water are needed for you and your family or what is the capacity of the water storage tank, measured in gallons. Details about sizing here.

The capacity of the water tank-type heaters ranges from 20 to 100 gallons, and the most popular sizes are 40, 50, 60, and 80-gallon tanks as they produce enough hot water for the family sizes of 4-6. These are known as the whole-house units that require some floor space and clearance around and above for the installation and service.

The best places for the installation are the utility room, laundry, basement, or garage. An attic is also used for the installation, but this location has some disadvantages that should be taken into account.

Note: Due to the higher recovery rate, you would choose a gas water heater with a lower capacity than an electric unit and for the same family size.

Small size hot water tanks of only a few gallons, like the electrical heater Ariston from Bosch or SHC Mini-Tank from Stiebel Eltron, are mainly used for point-of-use applications and are 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 the experts, the average life expectancy of the water tank heaters is 13 years. For tankless is longer, it is over 20 years.

Most of today's water heaters have a warranty of 6 years, while the good-quality ones equipped with one or more commercial-grade anodes come with a warranty of 12 years.

The warranty found on tankless models can reach 15 years.


Choose the right tank size so you can meet the demand at the peak time, but don't select an oversized model as the energy cost increases. Here is the sizing guide for more info. If you are not sure, ask a plumber or HVAC technician for advice.

First Hour Rate

Hot water delivery capability or first-hour rate is a combination of the tank capacity and recovery rate, or how much hot water it can produce in one hour.

Recovery Rate

The recovery rate shows how much hot water a water heater can produce in a given period. When comparing two water heaters, one model has a faster recovery rate if it has more BTU or Watts than the other model.

Keep in mind that the greater the demand for hot water is, the higher the recovery rate you need.


High-efficiency water heaters are more expensive but pay off faster; also, they come with higher quality, efficient energy use, and better warranties. They are also environmentally friendly.

Such models have 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). Higher - better.

Available features

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

But, available features might also be of your interest. Some include the advanced system such as the self-cleaning, diagnostic system and intelligent gas control valve. Also, the LED display, hot surface ignition, flue damper, power or direct venting, number of anodes, material quality, etc.

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Benefits of water tank heaters

  • Simple and proven design
  • Less demanding
  • Cheaper than tankless water heaters
  • High efficient and Energy Star models available
  • Condensing models available
  • Capacity ranges from 2 gallons to over 100 gallons
  • Several types (size) available; tall, short, lowboy
  • No minimum water flow is required; they can be used for low and high demanding applications.
  • If you have a gas-powered water heater, hot water is available even during the power outages.
  • Smaller gas requirements
  • Easily adapted for use in solar water heating
  • Great for smaller families


  • 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 tank-type water heater work?

Conventional water tank heaters have a very simple design that allows easy floor installation, vertically positioned. The main part is the water storage tank, usually made of metal, where hot water is stored and further used for a shower, bath, dishwashing, or washing machine.

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

Cold water enters the bottom of the storage tank through the dip tube (cold water inlet), and after it is heated by the gas burner or electric heating elements, hot water rises to the upper section of the tank. From there, it is transferred through the hot water outlet and to the open tap. At the same time, the hot water gets replaced with the cold water.

This process repeats, but it depends on the water temperature. If it is lower than the set value on the thermostat, the water heater keeps running; and once it reaches the set value, the heating stops.

Some models are equipped with innovative technology, such as sensors, flow valves, electronics, and electrodes, providing better performance, greater efficiency, and comfort.

Hot water tanks are also very safe. 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.

Note: Even with the simple design, tank water heaters have to be installed, maintained, and troubleshoot, so the recommendation is to contact the plumbing expert.


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

Tips to save money

Get a high efficiency model

If you have an old tank-type water heater, replace it with an energy-efficient heater, as the higher efficiency provides more savings in the long run. Look for condensing models, such as Vertex from AO Smith or Polaris.

Get the model that is solar-friendly.

Install an insulation blanket

How to check if your tank water heater is wasting energy? Put your hand on the outside surface of the tank, and if it feels warm, your unit needs better insulation. Once you install the insulation blanket or "jacket," the standby heat loss will decrease, and your savings increase, like energy-efficient units with thicker foam insulation. If you consider buying a new unit, choose one with the higher insulation value (R-24 will be the best).

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

You can also save if you lower the temperature on the water heater thermostat by a few degrees.

If you reduce the temperature on the thermostat by one degree for eight hours, you will reduce the energy consumption by one percent.

The recommended temperature is between 120 and 140 degrees F, while the factory set temperature is between 120 and 125 F.

Common water tank heater problems

There are many reasons your water heater is not working, and there is no hot water in your home.

If a gas water heater is not heating, the pilot light and thermostat failure are common issues.

If an electric type is not heating water, heating elements or thermostats might not be working properly.

Problems that are common for both types are:

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

Most repairs are DIY but if you are not comfortable troubleshooting and fixing it, call a professional.


Water tank heaters are good choices for small and mid-size households, where demand for hot water is not high, and for people who would like to stick to old and proven technology.

As opposed to tankless, storage tanks use the energy at a slow rate and store the heat for later use.

See how hot water tanks compare to tankless.

While most of the tanks are low efficient, there are still high-end models, whether electric or gas, that can come with an ultra-high efficiency of over 90%, innovative design, and significant savings. These are, as mentioned above, Polaris and AO Smith Vertex from the gas type or Rheem and AO Smith electric hybrids.

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