Best Gas Hot Water Heaters
Review & Buying Guide
(updated 2020)

The best gas hot water heaters are ultra-efficient, high performing, and environment-friendly systems, offering a great choice for homeowners looking to buy a brand new or upgrade an existing water heater.

Even if you already have an electric unit, you might want to switch to gas, because of all the benefits and savings natural gas and propane-powered water heating devices bring.

Let's see what these benefits are, how gas hot water heaters compare to electric, top-selling brands, prices, and where to shop for the best deal.

This review and corresponding links are about gas water heating in residential homes, powered by propane and natural gas, and are providing tips for buying either storage tank-type or tankless models. The articles also include reviews of the most popular manufacturers and models, installation and maintenance tips, the most common problems, and how to troubleshoot them.

Selecting a gas hot water heater - Things to consider

Choose a fuel source

Gas hot water heaters are designed to use both natural gas and liquid propane - LP. Most of the built and sold water heaters are factory set to use natural gas as it is widely used and cheaper than propane.

To run a propane water heater, you need a liquid propane (LP) storage tank and regular fuel delivery. The performance is similar to natural gas units.

When comparing natural gas vs. propane, it is worth mentioning that the energy factor (EF) is almost the same for most brands of gas heaters, both heating water fast.

Propane gas has two times more energy than natural gas (2,516 BTU vs. 1,030 BTU), but it is more expensive and requires frequent delivery from your propane dealer. A well established natural gas network provides a continuous gas supply from your utility company.

Both gas types are eco-friendly and are considered as "green fuels", emitting lower levels of "greenhouse" gases. When comparing them side by side, propane gas does not harm the environment, while natural gas does to some extent. When released into the atmosphere it is considered a greenhouse gas.

The gas conversion of gas water heaters should be performed by the licensed technician only. Such water heaters are properly labeled and will come with the conversion kit.

Choose a water heater type

There are two types of water heaters you can choose from; storage tank-type and tankless, which can be further divided into models with or without condensing technology.

Tank-type

Tank type water heaterTank-type

Tank-type water heaters are designed with the water storage tanks that have a capacity from as little as a few gallons to over 100 gallons, all used in residential homes. Hot water is always ready and available. The tank-type advantage over the tankless type is the lower cost and simpler design, so they are less prone to failures. The most advanced models utilize condensing technology, such as this Vertex model from AO Smith.

Recommended 50-gal models to buy

Tankless type

Navien tankless water heaterTankless

Tankless water heaters do not store hot water but heat water as needed - on-demand, while incoming water is passing through the heat exchanger. Hot water is not seating at the bottom of the unit because there is no storage tank, so it is always delivered fresh. The greatest advantages of tankless over the tank-type are their small and compact design, advanced technology, longer life, energy savings, and flexible installation.

Savings are even higher if you chose to go with the condensing, which also gets lower energy consumption and better environmental protection. Good examples are those from below, found as the best selling models.

Best selling gas-powered tankless type models

Determine the size you need

This is an important factor because a properly sized water heater will provide enough hot water for your home, resulting in increased comfort, efficiency, and savings. There will be a sufficient amount of hot water for busy families and during peak times.

Storage tank-type gas hot water heaters are usually installed in a designated room (utility room, basement, or garage), standing on the floor, while tankless, because of its small size and flexible venting options, almost anywhere (including bathrooms and kitchens), but mainly on the wall.

The most popular models are those with the tank capacity of 40, 50, and 60 gallons, as they can produce enough hot water for families of four and homes with up to 2 baths, yet still being affordable.

For the same family size, tankless water heaters with the flow rate of 8 gallons per minute, or more, will do the same work.

As per this article, we need approximately 20 gallons of hot water for a decent shower and 30 gallons to wash the clothes.

Also, when it comes to sizing a tankless, we will need around 2-3 gallons per minute for a shower and 2 gallons per minute for the washing machine.

Select the best venting option

Other important factors to consider when looking to buy one of the gas hot water heaters, are the options you have for efficient and cost-effective venting.

When the gas water heater is running, it requires fresh air for combustion and ignition, and it can be used either from indoors or from the outside. It is also vital to safely remove products of combustion/flue gases outside, using the house chimney or provided vents.

There are several types of venting systems one should consider:

  • A conventional, atmospheric vent is using the chimney. This is the simplest type and is often found with the low energy factor.
  • For the direct vent, no chimney, and blower needed, it vents directly out through the wall by using the provided vents.
  • The power vent is like the direct vent but with the help of the electrical power vent - blower, which allows more flexibility during installation. Most of the high-efficiency models are power vent.

Which gas water heater to buy?

If looking to buy the best tank-type gas heater, check out AO Smith GDHE-50-NG Vertex 100 or Polaris water heater, both with an ultra-high energy efficiency of 96%, making it the most energy-efficient models on the market. The first-hour rate on both units is very high, delivering hot water fast, and when needed.

If looking for the best tankless, the recommendation is to buy one of the condensing units, such as Takagi, Rinnai, or Noritz, as they are known for ultra-efficient water heating, fast hot water delivery when needed and in endless supply.

Gas versus electric water heaters

  • Heating with gas is two times faster than using electricity, so more hot water is available during peak hours.
  • Higher recovery rate. The 50-gallon gas hot water heater has an average recovery rate of 80-90 GPH, while the electric 50-gallon size has a recovery rate of approximately 60 GPH.
  • It costs less to operate than electric units.
  • They are high-efficient.
  • There is a variety of products, from tank heaters to tankless and a combination of gas-fired burners and tank-type heaters.
  • Ultra-efficient, condensing models are available.

Money-saving tip: If gas hot water heaters are expensive to buy, renting one is always an option. Renting a water heater is convenient and gives you peace of mind, so if anything goes wrong with the unit, most parts and services are covered.

If planning to switch from an existing heating system to a new one, using natural gas or propane, consider next:

  • Gas conversion is easy.
  • If there is no chimney, direct or power vented heaters are your best bet.
  • If the chimney already exists, it has to be checked by a professional, and if it is needed, perform cleaning or resizing. Other options include using a direct or power vent system that does not require a chimney.
  • It is also straightforward to replace an existing and old natural gas water heater with a newer one, but first, check the venting options in a home.
  • Older heaters are less energy efficient.

Main parts of the tank-type water heaters

  • A water tank to store water.
  • Glass lining for metal tank protection against corrosion.
  • Foam insulation - thicker is better.
  • A draft hood for the flue tube installation.
  • A flue tube to remove the products of combustion out.
  • An anode rod for corrosion protection. Some models are equipped with the stainless steel tank, so no anode rods are installed.
  • A dip tube for bringing the cold water inside the tank.
  • A drain valve for draining water during maintenance (for example).
  • Gas burner.
  • Gas combustion chamber.
  • Thermocouple safety element.
  • Pilot light or electrode for igniting the gas.
  • Gas valve.
  • An electric blower on power units to remove the gases out.
  • TPR Valve (Temperature and Pressure Relief Valve). This safety element protects from excessive temperature and pressure.
  • A thermostat to control the temperature of hot water.

How tank-type heater works

A tank-type water heater is designed to store hot water. It delivers hot water to the fixture once the hot water tap is open.

Hot water from the top of the tank starts running through the hot water outlet to the faucet or a shower. At the same time, cold water enters from the bottom through the dip tube.

As the thermostat senses lower temperature of the cold water, it turns on gas at the gas valve and the burner that is mounted at the base of the tank. A thermocouple, as a safety element, sends the signal to the gas valve to open, starting the ignition. Once the flame on the main burner is established, water is heated, while the products of combustion from the combustion chamber are removed through the flue vents out.

Conclusion

Buying a gas water heater is not easy and should not be done quickly - without considering all the factors.

Water heating accounts for close to 20% of your annual energy bill, so choose wisely.

Until now, tank-type heaters were considered as standard and preferred type for water heating by many homeowners. Today, homeowners have more options such as tank-type, tankless, hybrids, boilers, condensing, and non-condensing.

You can get a gas model for a little over $500, but you will get a base model that is low efficient and not much environmentally-friendly.

If you want to cut your energy costs, get a gas condensing model with an energy factor of at least 0.9, which has decent protection, including the powered anode, self-cleaning system, and power venting.

And if you have natural gas delivered to your house, use this fuel type because it is simply the most cost-effective solution for your home.

Related articles

Best models
Top 50-gal models
Natural gas
Propane gas
Direct vent
Power vent
Troubleshooting
Gas water heaters vs. heat pumps


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