Buying a new water heater used to be easier. With only the conventional tank-style heaters available, there were few options to choose from. Nowadays, technological advances have led to the development of different types of water heaters along with various electronic components and features that can make this purchase decision more challenging.
Since a water heater can be a substantial investment, it’s important that it lasts for years to come. Read on to learn what factors to consider when looking for a new water heater, to see some of the highest-rated products spanning several different categories, and to discover how to find the best gas water heater for the home.
- BEST OVERALL: Rinnai V65iN High Efficiency Tankless Water Heater
- RUNNER-UP: A.O. Smith Signature 100 40-Gallon Water Heater
- BEST BANG FOR THE BUCK: Sure Comfort 40-Gallon Natural Gas Tank Water Heater
- BEST TANKLESS: Rinnai RL94iN High Efficiency Tankless Water Heater
- BEST COMBINATION: Rheem Prestige High Efficiency Combination Boiler
- BEST 50-GALLON: Rheem Performance 50-Gallon Tank Water Heater
How We Chose the Best Gas Water Heaters
Selecting the top water heaters for this list began with extensive research into a broad pool of products to find the best options available based on key efficiency, size, and performance factors. Finding the right water heater can make the difference between a warm, relaxing shower or an abrupt awakening as cold water suddenly bursts from the shower head. With that in mind, size and capacity played a major role in determining the top options for this list.
However, even if the water is nice and warm, it can be difficult to de-stress if bills are on the mind, so operational efficiency was also a key consideration during the selection process. Products with high efficiency, durable construction, and appropriate size or output capacity for an average household tended to stand out from units that were too small, large, or costly.
Our Top Picks
The list of top options included below were selected based on the installation difficulty, maintenance requirements, energy-efficiency ratings, size, and capacity.
One of the main disadvantages of many tankless water heaters is the cost of the unit, but Rinnai’s tankless unit is a powerful water heater at an affordable price. This tankless unit boasts an EF rating of 0.82 but still generates enough power to produce a 6.5-GPM flow rate that brings continuous hot water to a four-person household. Although it will still be more expensive to install than a conventional storage-tank heater, its compact size offers a wider range of location options, and it won’t take up precious floor space in the home.
- Type: Tankless
- Capacity: 6.5 GPM
- EF rating: 0.82
- The high-efficiency operation can reduce costly household energy bills
- Replacing a tank-style heater with this tankless heater increases floor space in the home
- At a flow-rate capacity of 6.5 GPM, this heater is suited for a 4-person household
- Users get on-demand hot water that won’t run out in the middle of a shower
- Installation of this unit will typically require new water and gas supply connections
Get the Rinnai V65iN gas water heater at Amazon, The Home Depot, or Wayfair.
A.O. Smith’s 40-gallon water heater offers features similar to more expensive units but at a fraction of the price. It features a 40,000-BTU burner that can satisfy the hot water demands of a three- to four-person household and can deliver as much as 67 gallons in the first hour to avoid the hassle of running out of hot water when demand is high. It’s also equipped with an LED display for diagnostic reporting, push-button ignition, an electronic gas valve for precise temperature regulation, and safety features that prevent accidental fires from vapor ignition.
- Type: Storage tank
- Capacity: 40 gallons
- EF rating: 0.58
- The 40-gallon tank is well suited for homes with 3 or 4 people
- 40,000-BTU burner provides powerful heating capabilities to warm the tank contents rapidly
- Users can get as much as 67 gallons in the first hour of operation
- Electronic gas valve ensures precise temperature control for optimal user comfort
- Relatively low efficiency rating may indicate an increase in energy bills with this unit
Get the A.O. Smith gas water heater at Lowe’s.
For an affordable water heater that doesn’t compromise on functionality, this 40-gallon water heater from Sure Comfort might be all that is needed to replace the water heater affordably. Although it’s not the most powerful unit on the list, the 34,000-BTU burner is plenty for a household of two to four people and delivers 67 gallons of hot water in the first hour of operation. Its tall and sleek design is made to make installation easier, which may even reduce the cost of installation.
- Type: Storage tank
- Capacity: 40 gallons
- EF rating: 0.59
- Modest 40-gallon tank is a good option for homes with 2 to 4 people
- Wait time for hot water is short, with 67 gallons in the first hour
- Tall, slim design reduces the amount of floor space required for installation
- This unit is not a high-efficiency option, so operation could increase energy bills
Get the Sure Comfort gas water heater at The Home Depot or Menards.
A tankless unit may be the best bet to get an energy-efficient water heater that takes up a small amount of space. Rinnai’s tankless water system has a high EF rating of 0.81 but is still powerful enough to generate a 9.8-GPM flow rate that is large enough to satisfy the hot-water demands of a four-plus-person household. Since it only measures 23 inches high and 14 inches wide, it can be installed in out-of-the-way places like an attic, basement, and crawl space without taking up floor space like a conventional storage tank heater.
It also comes equipped with an integrated scale-detection feature that monitors for mineral deposits and corrosion buildup so users can stay on top of maintenance and maximize the life of the unit. This tankless heater is also more affordable than many tankless systems, but is still more expensive than storage tank models.
- Type: Tankless
- Capacity: 9.8 GPM
- EF rating: 0.81
- Integrated scale-detection feature monitors maintenance needs
- Compact body mounts directly to the wall to save space
- High output capacity of 9.8 GPM is great for larger households
- Users can save on energy costs with this unit’s high 0.81 efficiency rating
- DIY installation may void the warranty due to a high number of improperly installed units
Get the Rinnai RL94eP gas water heater at The Home Depot or Build With Ferguson.
For those tired of wasting money to power a central heating boiler and water heater, a combination water heater may be an attractive option. This combi boiler from Rheem boasts a 9.9 GPM output capacity that can satisfy the hot-water demands of a home with up to 2.5 bathrooms while using the least amount of energy possible—an AFUE rating of 95 percent. It also features a room air-intake vent to eliminate the need to install an intake vent to the outside, and the exhaust vents are compatible with PVC to further reduce installation expenses.
- Type: Combination
- Capacity: 9.9 GPM
- EF rating: 0.95
- Impressive flow rate of 9.9 GPM is more than enough for the average household
- At an EF of 0.95, this unit boasts one of the highest efficiency ratings available
- Includes a room air-intake vent to help reduce installation costs
- Complex installation procedure requires the services of a professional installer
- Not a practical investment for homes that already have a furnace
Get the Rheem combination gas water heater at The Home Depot or ABR Wholesalers.
For a no-frills storage hot water tank that offers enough power and storage capacity for a three- to five-person household, Rheem’s 50-gallon water heater might be just what’s needed. It features a 38,000-BTU burner that can deliver an impressive 85 gallons of water in the first hour. The tank’s narrow profile was designed for ease of installation in a variety of indoor spaces, so the unit’s affordable price point is complemented by a potentially reduced installation cost. However, its EF rating of 0.63 won’t save as much money on the utility bill as other more efficient units.
- Type: Storage tank
- Capacity: 50 gallons
- EF rating: 0.63
- 38,000-BTU burner can heat up to 85 gallons of water in the first hour
- Tall 50-gallon tank provides enough water for a four- or five-person home
- Narrow size reduces the space required for the installation of this unit
- Moderate 0.63 efficiency rating isn’t overly helpful in reducing energy costs throughout the year
Get the Rheem Performance 50-gallon-tank gas water heater at The Home Depot or DSL Supply.
What to Consider When Choosing a Gas Water Heater
Opting for gas water heaters over electric water heaters somewhat narrows the search, but there are still several other factors to consider when selecting the perfect one for the home. There are different types of gas water heaters with different installation and maintenance requirements, energy-efficiency ratings, storage capacities, and safety considerations. Take the following considerations into account when looking for the best water heater to meet the specific needs of a home.
There are three primary types of residential gas water heaters: storage tank, tankless, and combination units.
Storage-tank water heaters are the most common type. Tank water heaters consist of an insulated tank that uses a flame burner to warm the water stored inside and a thermostat that regulates the temperature of the water in the tank. Typical tank sizes include 40-gallon and 50-gallon tanks, though there are both smaller and larger tanks available. The heated water stored in the tank supplies all the hot water to the faucets and appliances. The primary disadvantage of tank water heaters is that it takes time for the tank to refill and reheat after the hot water in the tank is depleted from use, like after a long shower, so don’t expect to have hot water for the first hour. Water heater blankets can help insulate the tank, reduce heat loss, and increase the efficiency rating.
Tankless water heaters don’t store a large reservoir of hot water but use a compact boiler that heats water only when hot water is needed. Also called on-demand water heaters, they are similar to running a hot water faucet or shower valve, which makes them significantly more energy efficient. Since they don’t rely on preheating and storing a large reservoir of water, the risk of running out of hot water is less than with a storage tank heater. However, a tankless water heater might not keep up with an excessive demand for hot water if it doesn’t have sufficient output capacity. The other disadvantage of tankless systems is that they’re more expensive to purchase and install.
Combination water heaters, sometimes called combi boilers, combine a water heater and a central heating boiler into a single high-energy-efficient unit. They use energy to heat a single unit that’s responsible for both the home’s heating and hot water instead of requiring energy to fuel two separate appliances. The primary disadvantage of these units is that they’re incredibly expensive to purchase and install and are only practical for homes that are heated with an existing boiler, not a furnace. Although they’re rarely seen in American residences, they’re popular in the United Kingdom, where they account for more than half the boilers installed in newly constructed residences. In the United States, they’re most often used in small apartment complexes.
Size and Capacity
The water-storage capacity of tankless and combination water heaters can range from 20 to 100 gallons, with the most common options being 40-gallon gas water heaters and 50-gallon gas water heaters. The general rule of thumb for determining hot water needs is to add 10 gallons for each person in the household. A 40- to 50-gallon gas water heater tank should be plenty for a four-person home.
A tankless water heater’s capacity is determined by the flow rate in GPM. A home’s needed flow rate for a tankless water heater depends on the number of people in the household and the flow rate required by each of the hot water fixtures, including the kitchen sink, bathroom sinks, shower, and tub. Each fixture requires a certain flow rate for optimal operation, and more people in the home means there is a higher likelihood that more than one fixture will be running simultaneously. Generally speaking, a household with fewer than four adults needs a tankless water heater with a flow rate of between 3 and 5 GPM, while a household with more than four adults may need a heater with a flow rate between 6 and 10 GPM.
Combination boilers will have different sizes and capacities depending on the size of the existing boiler that will be replaced. Therefore, it’s best to consult a professional installer when determining the size and capacity of the combi boiler.
Direct-Fired vs. Indirect-Fired
Storage-tank water heaters can heat water through either a direct-fired or indirect-fired process. Direct-fired heaters have their own burner that heats the water in the tank directly. They have an open-flame burner integrated into the tank, so exhaust needs to be released through ventilation lines to the outside. Direct-fired heaters are the most common type since they’re typically more affordable, energy efficient, and can be installed in any home.
Indirect-fired heaters use a boiler that’s separate from the storage tank. Heat transfer coils act as a heat exchanger to transfer the heat from a separate boiler, typically the boiler used for the home’s central heating, to the water in the storage tank. Depending on the distance between the water tank and the boiler, they may be less energy efficient. However, they require less maintenance since they don’t have a burner that can experience mechanical defects or gas and ventilation lines that need to be periodically serviced. They also can be potentially more energy efficient than direct-fired heaters since they passively utilize the heat generated from a boiler or furnace already running to heat the home. Indirect-fired heaters can only be installed in homes already equipped with compatible boilers and don’t require any ventilation since no combustion occurs at the tank.
The energy efficiency of a water heater refers to the amount of energy that is actually used to heat the water. This is an important factor to consider since water heaters are the third most energy-demanding appliance in most homes and can account for as much as a quarter of the monthly utility bill. Every new water heater comes with an EF efficiency rating that indicates the percentage of heat energy that’s used to heat the water. The EF factor is expressed as a ratio instead of a percentage, but an EF rating of 0.7 means that it converts 70 percent of the energy used into heat. Combination water heaters use the AFUE rating, which expresses energy efficiency as a percentage and is the rating standard used for boilers.
Although gas water heaters are less efficient than electric water heaters, gas is usually considerably cheaper than electricity, which will likely translate to a reduced overall operating cost. Regardless of fuel source, tankless water heaters are much more efficient than storage tank peers and can reduce the monthly energy bill by up to 40 percent.
Water heaters are generally safe to use, but there are still some important safety considerations to keep in mind. Direct-fired water heaters require proper ventilation to allow the toxic and flammable exhaust gasses to escape to the outdoors. Proper temperature regulation of the water inside the tank is also important to avoid the water getting too hot or too cold. Water temperatures that are too high, above 140 degrees Fahrenheit, can cause scalding burns on people exposed to the hot water. Water temperatures that are too low, below 120 degrees Fahrenheit, can cause bacterial growth and an increased risk of contracting Legionnaires’ disease.
Water temperatures inside a water tank in excess of 212 degrees Fahrenheit can turn into steam, which will increase the pressure in the water tank and possibly cause an explosion. Fortunately, water heaters have temperature and pressure relief (T&P) valves to prevent this from happening by automatically relieving the tank’s internal pressure when a high enough pressure is reached. Inexperienced DIYers should never attempt to relieve the T&P valve manually by themselves but should contact a professional plumber if they are concerned about the water heater’s temperature or pressure levels.
Installing either gas or electric water heaters can be an expensive and labor-intensive task that requires a considerable knowledge base and skill set. As a result, it’s not a task that should be attempted as a DIY project but should be done by a professional plumber.
Installing a tankless water heater without prior experience is especially discouraged since new natural-gas and water-supply lines often need to be installed. Installing a combination water heater is also a highly complicated procedure that should be reserved for professionals. Depending on location, the cost of installing a storage tank water heater can range from $800 to $1,300; installing a tankless water heater usually costs between $1,000 and $3,500; and the cost of installing a combination water heater can be between $3,500 and $8,000.
Unlike installation, a water heater can be easily maintained by the average DIYer. Regardless of the type of water heater, the primary maintenance consideration is the removal of mineral and sediment buildup. Mineral deposits will accumulate in the storage tank over time, causing corrosion that can reduce the energy efficiency and lifespan of the heater.
For storage-tank heaters, it’s recommended to flush the tank every 2 years. This is done by shutting off the gas and water supply to the tank, attaching a hose to the drain valve at the bottom of the tank, running the hose outside, and then opening the tank’s drain valve until it’s completely flushed. Take care to position the hose correctly and ensure there are no leaks, otherwise there may be gallons of hot water pouring into the home.
Tankless water heaters need to be flushed more often, usually once or twice a year since mineral deposits tend to accumulate more rapidly. Most tankless heaters have purge valves accessible under the tank’s lid to accommodate a hose attachment so it can be flushed like a storage-tank heater. Simply shut off the water supply and propane or natural gas, then connect the hose, run the hose outside, and open the purge valves. It’s also recommended to rinse the heat exchanger with vinegar to remove accumulated mineral deposits from the coils.
There’s a lot of information to digest when you’re considering a new water heater, so you may still have some questions about propane, natural gas, or even electric water heaters. Consider the following answers to some of the most frequently asked questions below to help satisfy your curiosity.
Q. What are the disadvantages of tankless water heaters?
Installing a tankless water heater instead of a 40- or 50-gallon tank seems like an obvious choice. However, cost is the main disadvantage of tankless water heaters since the units are typically more expensive to purchase, and they’re also more expensive to install. Additionally, a small tankless water heater may not be able to keep up with the demands of a home that previously used a 60- or 80-gallon gas water heater, so it’s important to keep the capacity of the water heater in mind before purchase.
Q. Will a gas water heater keep the water warm in the entire house?
If you purchased a gas water heater with a sufficient capacity to satisfy your home’s hot-water demands, it should easily be able to keep the water warm in your entire house.
Q. Can I replace my own water heater?
Unless you’re an experienced plumber, it’s generally recommended to hire a professional to install your new water heater.
Q. How long do gas water heaters last?
Gas water heaters can last between 8 and 20 years.
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