10 Best 40 Gallon Gas Water Heater We've Tested 2025: Top Rated

Source: Amazon

Best Mid-Size Performance: 40 Gallon - 34,000 BTU Residential Ultra Low NOx Gas

Pros:

• Strong 34,000 BTU Output

• 81-Gallon First Hour Delivery

• Ultra Low NOx Emissions

• Reliable 6-Year Warranty

Cons:

• Not Energy Star Rated

This 40-gallon Ultra Low NOx gas water heater is designed for mid-size households of three to four people, offering a solid balance of power and efficiency. With a 34,000 BTU input and an 81-gallon first-hour delivery rate, it provides consistent hot water without noticeable drops in temperature during peak use. Its atmospheric vent design supports reliable ventilation, while the 80% recovery efficiency ensures quick reheating after heavy demand. Built with a durable silver steel jacket and compact 18-inch diameter, it fits comfortably in most utility spaces without taking up excess room.

From a customer perspective, this model appeals to homeowners seeking dependable performance without paying a premium for Energy Star certification. Users often appreciate its steady output, straightforward installation, and clean combustion that meets Ultra Low NOx standards. While it may not be the most energy-efficient option on the market, it delivers long-term reliability and strong heating capacity at a fair value for everyday residential use.

Best Safety Features: Rheem PROG40-40N RH67 PV Professional Classic Residential 40K BTU Power

Pros:

• Exclusive Air/Fuel Shut-Off

• Long Venting up to 100 ft

• Maintenance-Free Design

• Durable R-Tech Anode Rod

Cons:

• Requires Indoor Installation Only

The Rheem 40-gallon gas water heater combines safety, efficiency, and convenience for residential use. With a compact 21-inch width and 65-inch height, it fits comfortably indoors while using household air for combustion and safely venting exhaust through its integrated blower system. The standout feature is its exclusive air/fuel shut-off device, which automatically cuts off gas flow in unsafe conditions—an advantage that enhances household safety. The R-Tech anode rod adds long-term tank protection by resisting corrosion, extending the unit’s service life.

From a user standpoint, this model is ideal for homeowners prioritizing low maintenance and peace of mind. Customers appreciate the quiet operation, long venting flexibility, and the fact that it requires no filter cleaning. While it’s limited to indoor installations, its reliable performance and safety-focused engineering make it a strong contender for those seeking a long-lasting, worry-free water heater.

Best Compact Electric: Bradford White 40 Gallon - Upright Energy Saver Electric Residential

Pros:

• High 0.95 Energy Factor

• 6-Year Warranty Coverage

• Compact 22-Inch Diameter

• Quiet, Maintenance-Free Operation

Cons:

• Not Energy Star Rated

This 40-gallon electric water heater offers a dependable and space-efficient solution for smaller households of two to three people. Operating at 4500 watts and 240 volts, it delivers a solid 55-gallon first-hour output, ensuring a consistent hot water supply during daily use. The 0.95 energy factor indicates strong efficiency for an electric model, while the glass-lined steel construction enhances durability and corrosion resistance. Measuring 22 inches in diameter and 48.6 inches in height, it fits neatly into tight spaces, making it suitable for apartments or smaller homes.

From a consumer standpoint, this unit stands out for its simple setup and quiet, maintenance-free operation. Homeowners appreciate the reliable heating performance and balanced energy use, though some may note the lack of Energy Star certification. Overall, it provides excellent value for those seeking a compact, long-lasting, and efficient electric water heater with minimal upkeep.

Best High Flow Rate: State Proline Atmospheric Vent Series 40 Gallon Capacity 40,000 BTU

Pros:

• 78-Gallon First Hour Rating

• 42-Gallon Recovery at 90°F Rise

• Compact 18-Inch Diameter

• Durable Brass Construction

Cons:

• Moderate Energy Efficiency (UEF 0.65)

This 40-gallon gas water heater is built for steady, high-volume performance in busy households. With a first-hour rating of 78 gallons and a recovery rate of 42 gallons per hour at a 90°F temperature rise, it easily supports multiple simultaneous uses without noticeable drops in water temperature. The slim 18-inch diameter allows for flexible installation in narrow spaces, while its sturdy brass components contribute to long-term durability and reliability.

From a user perspective, this model is appreciated for its strong flow rate and consistent hot water delivery, particularly in homes with multiple bathrooms or high-demand periods. Customers value its balance between power and size, though the 0.65 Uniform Energy Factor means it’s not the most energy-efficient option available. Still, for those prioritizing fast recovery and dependable performance over maximum efficiency, it remains a practical and durable choice.

Best Slim Electric Design: State Proline Series 40 Gallon Capacity 4.5 kW Heating

Pros:

• 0.92 Uniform Energy Factor

• 53-Gallon First Hour Rating

• Durable Multi-Metal Construction

• Space-Saving 18-Inch Diameter

Cons:

• Moderate Recovery Rate

This 40-gallon electric water heater combines efficiency and compact design, making it ideal for homes with limited installation space. Delivering a 53-gallon first-hour rating and a 21-gallon recovery rate at a 90°F temperature rise, it provides steady performance for small to mid-size households. With 4500 watts of power and a 240-volt connection, it ensures quick and consistent heating while maintaining a solid 0.92 energy factor for cost-effective operation. The use of brass, copper, and stainless steel materials adds durability and corrosion resistance, extending the unit’s service life.

From a user standpoint, this model is favored for its sleek profile, quiet operation, and efficient performance. Homeowners appreciate its low maintenance requirements and dependable daily output, particularly in homes with moderate water demands. While its recovery rate may be slower than high-end models, its combination of reliability, efficiency, and compact form makes it a strong option for long-term residential use.

The best brand of gas water heater can vary depending on individual needs and preferences. Some well-regarded brands in the market include Rheem, Bradford White, AO Smith, and Navien. It is recommended to consider factors such as energy efficiency, reliability, customer reviews, and warranty when choosing the best brand for a gas water heater. Additionally, consulting with a professional plumber or researching consumer reports can provide valuable insights into the performance and durability of different brands.

How much should I pay for a 40 gallon water heater?

The price of a 40-gallon water heater can vary depending on several factors such as the brand, quality, and additional features. On average, you can expect to pay anywhere between $400 to $900 for a 40-gallon water heater. It is recommended to research and compare prices from different retailers or websites to find the best deal that suits your needs and budget.

Is a 40 gallon gas water heater big enough?

A 40-gallon gas water heater is generally considered sufficient for most households. It can provide an ample supply of hot water for a family of three to four people. However, the actual suitability of a water heater depends on factors such as the hot water usage patterns and the number of bathrooms in the home. If you have a larger family or frequently use multiple hot water appliances simultaneously, you may want to consider a larger capacity water heater. It is also important to note that insulation and energy efficiency play a role in the overall performance of the water heater.

Should I get a 40 or 50 gallon water heater?

The decision to get a 40 or 50 gallon water heater depends on your specific needs. Consider factors such as the number of people in your household, your hot water usage, and any future changes that may affect your water usage.If you have a smaller household with 1-2 people, a 40 gallon water heater may be sufficient for your needs. This size is typically suitable for average daily hot water usage, including showering, washing dishes, and laundry.

However, if you have a larger household with 3 or more people, or if you frequently use hot water for activities such as running multiple showers simultaneously or filling large tubs, a 50 gallon water heater would provide a greater supply of hot water and reduce the chances of running out.

It's also important to consider any potential future changes in your household, such as the arrival of additional family members or guests staying for extended periods. If you anticipate an increase in hot water usage, opting for a 50 gallon water heater would be a wise choice.

Ultimately, the decision between a 40 or 50 gallon water heater comes down to your specific hot water needs. Assess your household's requirements and choose the size that will comfortably meet those needs both now and in the foreseeable future.

Read More:

10 Best Electric Hot Water Heater We've Tested: Top Rated

10 Best 50 Gallon Gas Water Heater: Reviewed By SHR

In conclusion, choosing the best 40 gallon gas water heater comes down to balancing efficiency, reliability, and long-term performance. A high-quality model should deliver consistent hot water for medium-sized households while keeping energy costs manageable. Features such as fast recovery rates, durable tank construction, and advanced safety mechanisms make a significant difference in everyday comfort and peace of mind. By comparing models based on energy factor ratings, warranty coverage, and maintenance requirements, homeowners can confidently invest in a water heater that ensures both comfort and cost savings for years to come.