Gas Hot Water Heaters Guide | Pros and Cons

Gas hot water heaters offer homeowners an effective and popular option for high-efficiency and performance while reducing environmental impact.

In this article, we’ll explore the benefits of gas hot water heaters, compare them to electric models, and provide information on top-selling brands, prices, and where to find the best deals. We’ll focus on gas water heating in residential homes, covering propane and natural gas-powered storage tank-type or tankless models, as well as tips for installation and maintenance. We’ll also include reviews of popular manufacturers and models, troubleshooting common problems, and how to resolve them.

Table of Contents

How to Select a Gas Water Heater

Selecting the right gas water heater can be a daunting task, with a variety of types, sizes, and features to consider. Whether you’re upgrading your current unit or purchasing a new one, it’s important to choose a model that fits your household’s hot water needs, budget, and energy efficiency goals.

In this section, we’ll guide you through the key factors to consider when selecting a gas water heater, including size, efficiency, fuel type, and features, to help you make an informed decision.

Choose a Fuel Source

When choosing a gas water heater, you’ll need to decide between natural gas and propane. The right fuel type for your household depends on availability, cost, and efficiency.

If natural gas is available in your area, it’s often the more affordable and efficient choice. It’s also a cleaner-burning fuel than coal or heating oil, and produces fewer greenhouse gas emissions. However, if natural gas isn’t an option, propane is a good alternative.

Propane is more portable than natural gas, making it a popular choice for rural areas or off-grid homes. It’s also more energy-dense, meaning it can produce more heat per unit of fuel compared to natural gas. However, propane is typically more expensive than natural gas and requires a propane storage tank.

To run a propane 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 Uniform Energy Factor (UEF) is almost the same for most brands of gas heaters, both heating water fast.

Propane gas has twice the energy of natural gas (2,516 BTU vs. 1,030 BTU), but it is more expensive and requires frequent delivery from your propane dealer. As opposed to inconvenient propane delivery, a well-established natural gas network provides a continuous gas supply from your utility company.

Both gas types are eco-friendly and are considered “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, so when released into the atmosphere, it contributors to greenhouse gases.

To ensure safety and proper operation, the conversion of gas hot water heaters from one gas type to another should only be performed by a licensed technician. These devices are properly labeled and come with a conversion kit. According to A.O. Smith, the conversion of a gas unit from natural gas to LP gas (propane) is not permitted, but is allowed from LP to natural gas.

Choose a Gas 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 groups with and without condensing technology.

Tank-Type

Tank-type water heaters are designed with water storage tanks that have a capacity ranging from a few gallons to over 100 gallons and are used in residential homes.

Hot water is always readily available with tank-type models. The advantage of tank-type over tankless models is their lower cost and simpler design, making them less prone to failures.

The most advanced models utilize condensing technology, such as this Vertex model from AO Smith.

Tankless Type

Tankless water heaters heat water on-demand, as water passes through the heat exchanger. Since there is no storage tank, hot water is always fresh and clean. The main advantages of tankless models over tank-type heaters are their small, compact design, longer lifespan, energy efficiency, and flexible installation options.

If you choose a condensing model, you can enjoy even greater energy savings and environmental benefits. See below for some examples of the best-selling tankless models.

Determine the Size You Need

The proper sizing of a water heater is crucial in ensuring sufficient hot water supply for your home, resulting in increased comfort, efficiency, and savings.

Tank-type gas hot water heaters are typically installed in a designated room on the floor, while tankless options can be mounted almost anywhere due to their small size and flexible venting options, including bathrooms and kitchens, primarily on the wall.

The most popular tank-type models come in 40, 50, and 60-gallon capacities, providing enough hot water for families of four and homes with up to two bathrooms while remaining affordable.

For tankless devices, a flow rate of 8 gallons per minute or more can deliver the same amount of hot water for families of the same size.

According to this article about sizing, a decent shower requires approximately 20 gallons of hot water, and 30 gallons are necessary for washing clothes.

For sizing a tankless, you’ll need around 2-3 gallons per minute for a shower and 2 gallons per minute for the washing machine.

Select a Gas Model With the Most Advanced Features

Over the years, gas hot water heaters have evolved significantly with the incorporation of advanced features and technologies. These features not only enhance the functionality and efficiency of the units but also improve safety and convenience. From self-cleaning systems to WiFi connectivity, there are numerous advanced features that you can consider when purchasing a gas unit. In this regard, it’s essential to understand the benefits of each feature to make an informed decision that meets your needs and budget.

Digital displays and control panels: These allow for easy monitoring and adjustment of the temperature and other settings of the device.
Intelligent gas control valve. The intelligent gas control valve is an advanced feature in gas hot water heaters that uses sensors and microprocessors to adjust gas flow and temperature in real-time. This results in better energy efficiency and a more consistent supply of hot water. It may also have safety features such as built-in diagnostics to detect potential issues.
Energy-saving modes: Some gas models come with energy-saving modes, which can help you save on your energy bill by reducing the amount of gas used to heat the water.
Smart connectivity: Some gas hot water heaters can be connected to a Wi-Fi network and controlled remotely using a smartphone app, allowing you to monitor and adjust the settings from anywhere.
Self-cleaning systems: These systems help to prevent the buildup of sediment and other minerals in the tank, which can reduce the efficiency and lifespan of the unit.
Powered anode rods. They are often used in the most advanced gas water heaters because they are more durable and longer-lasting than traditional sacrificial anode rods. They are also more effective at preventing corrosion in high-demand environments where the heater is frequently used.
Leak detection systems: Some gas hot water heaters come with sensors that can detect leaks and automatically shut off the gas supply to prevent dangerous gas buildup.
Power venting: Power venting is a system that uses a fan to remove exhaust gases from the unit, which can improve efficiency and safety.

Select the Best Venting Option

Other important factors to consider when buying a gas hot water heater are the options for efficient and cost-effective venting.

When the heater runs, it needs fresh air for combustion and ignition, which can come from indoors or the outdoor atmosphere. It’s also essential to safely remove flue gases outside using the house chimney or provided vents.

There are several types of venting systems to consider:

Conventional atmospheric venting uses the chimney and is the simplest type but is often found with low energy factor models.
Direct venting doesn’t need a chimney or blower and vents directly out through the wall using provided vents.
Power venting is similar to direct venting but uses an electrical power vent blower, providing more installation flexibility. Most high-efficiency models use power venting.

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, both boasting an ultra-high energy efficiency of 96%. These models also have a high first-hour rate, ensuring fast and reliable hot water delivery.

If looking for the best tankless, consider buying one of the condensing units, such as Takagi, Rinnai, or Noritz. These models are known for their ultra-efficient water heating and ability to deliver hot water on demand and in an endless supply.

Comparing Pros and Cons of Gas Versus Electric Water Heaters

Ultimately, the choice between a gas or electric water heater will depend on your household’s specific needs, budget, and preferences. By weighing the pros and cons of each type, you can make an informed decision that meets your hot water needs while also being energy-efficient and cost-effective.

In this section, we will compare both types.

Fast heating. 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 gas than electric units.
Gas models are more powerful.
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 also 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 you are considering switching from your existing heating system to a new one that uses natural gas or propane, here are some important things to keep in mind.

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.

The Main Parts of Tank-Type Water Heaters

Water tank: A tank that stores the hot water until it is needed.
Glass lining: A layer of glass that protects the metal tank from corrosion.
Foam insulation: A layer of foam insulation that helps to keep the water hot for longer periods and reduces heat loss.
Draft hood: A hood that helps to remove the fumes produced during combustion outside the home.
Flue tube: A tube that carries the fumes produced during combustion outside the home.
Anode rod: A metal rod that is installed in the tank to prevent corrosion.
Dip tube: A tube that delivers cold water to the bottom of the tank.
Drain valve: A valve that allows for the draining of the tank during maintenance or repairs.
Gas burner: A burner that heats the water by burning gas.
Gas combustion chamber: A chamber where the gas is burned.
Thermocouple: A sensor that detects if the pilot light is on and regulates the gas flow accordingly.
Pilot light or electrode: A component that ignites the gas.
Gas valve: A valve that controls the gas flow to the burner.
Electric blower: A component that removes the fumes produced during combustion outside the home (found in power units).
TPR valve: A safety valve that prevents the tank from overheating or over-pressurizing.
Thermostat: A device that controls the temperature of the hot water.

How Gas Tank-Type Heater Works

A gas tank-type water heater works by heating water in a tank using a gas burner located at the bottom of the tank. When hot water is needed, cold water enters the tank through a dip tube and is heated by the gas burner. The hot water then rises to the top of the tank where it is drawn off through a hot water outlet and used for washing, bathing, or other purposes.

The gas burner is controlled by a thermostat that senses the temperature of the water in the tank and turns the burner on or off as needed to maintain a consistent temperature.

To ensure safe operation, the tank is equipped with several safety features, including a TPR (Temperature and Pressure Relief) valve, which releases pressure if the temperature or pressure inside the tank becomes too high. There is also a thermocouple design to send the signal to the gas valve to open and starting the ignition, and to prevent gas leak if the pilot light goes out.

To vent the products of combustion out of the home, the tank is equipped with a flue tube and draft hood.

Are Gas Water Heaters Safe?

Gas water heaters are generally considered safe, but there are potential safety risks that homeowners should be aware of.

Gas leaks can occur if there is a problem with the gas line, gas valve, or gas connection. This can result in a dangerous buildup of gas in the home, which can lead to explosions or fires.

Carbon monoxide poisoning is another potential risk associated with gas-powered appliances that are not properly vented. Carbon monoxide is a colorless and odorless gas, which can accumulate in the home and lead to headaches, nausea, dizziness, and even death.

Fires can also occur if a gas unit is not properly installed, maintained, or operated. For example, if the flue is blocked or damaged, it can cause the heater to overheat and potentially catch fire.

Overall, gas water heaters can be safe and reliable if they are installed and maintained properly, and if appropriate safety precautions are taken. It’s important to work with a licensed professional to ensure that your device is installed correctly, and to have it serviced regularly to prevent potential safety risks.

What Is the Lifespan of a Gas Water Heater (and Warranty)?

The lifespan of a gas water heater can vary depending on several factors, such as the type of heater, quality of the unit, frequency of use, and the quality of the water being heated.

In general, tank-type devices have a lifespan of 10-15 years, while tankless models can last up to 20 years or more.

Regular maintenance can also help extend the lifespan of a gas water heater. Flushing the tank annually to remove sediment buildup, checking and replacing the anode rod as needed, and ensuring proper ventilation and safety features are in place can all contribute to a longer lifespan for the unit.

When purchasing a new unit, it’s important to consider the warranty offered by the manufacturer. The warranty can provide some protection against defects and premature failure of the unit.

Most warranties cover the tank and parts for a period of 6 to 12 years, with some tankless models offering longer warranties of up to 15 years.

It’s important to read the warranty terms carefully to understand what is covered and for how long.

Cost of Gas Water Heaters

Gas hot water heaters can vary in cost depending on the type and features of the unit. The price range for a basic tank-type model can start at around $500, but more advanced models with features like high energy efficiency and longer warranties can cost upwards of $1,000.

Tankless gas heaters tend to be more expensive, with prices ranging from $700 to $2,000 or more. It’s important to consider both the upfront cost and long-term energy savings when deciding on a gas water heater.

Conclusion

Buying a gas hot water heater is a decision that should not be made hastily, as it can impact your energy bill and household budget.

While tank-type heaters have been the standard for many years, there are now many options available, including tankless, hybrids, boilers, condensing, and non-condensing models.

It’s important to consider factors such as energy efficiency, cost-effectiveness, and safety features when making your decision.

Gas condensing models with an energy factor of at least 0.9 are a great option for those looking to cut energy costs, and natural gas delivery can provide a cost-effective solution for your water heating needs.

By taking the time to carefully consider all the factors, you can choose a gas water heater that fits your needs, saves you money, and ensures safety and peace of mind.

Best Gas Hot Water Heaters for Home Use: Buying Tips, Pros and Cons