10 Best 40 Gallon Gas Water Heater of December 2025

• Blue Diamond glass coating provides superior corrosion resistance to industry-standard glass lining
• Self-powered electronic gas valve uses thermopile to generate power needed to operate the electronic gas control without requiring external power
• Internal microprocessor provides enhanced operating parameters and tighter differentials for precise sensing and faster heating response
• Dynaclean diffuser dip tube helps reduce lime and sediment buildup, maximizes hot water output; made from long-lasting PEX cross-linked polymer
• Meets all current regulations set forth by the National Appliance Energy Conservation Act (NAECA)

A. O. Smith

• Heavy gauge Steel tank
• Inner Dura glas lined tank fired at 1,600°f for optimum protection from the effects of corrosion
• Factory installed Brass drain valve on all models allows for easy draining of the unit which reduces sediment deposits extending tank life
• Factory installed Brass temperature/pressure relief valve
• American standard point-of-use electric water heaters are all certified at 300 psi test pressure and 150 psi working pressure. All tanks are also 100% hydrostatically tested at the factory

American Standard Water Heaters

• Includes 4500 watt elements
• Non-simultaneous
• Protective magnesium anode rod - provides added protection against corrosion for long trouble-free service
• Package Dimensions: 23.0" L x 23.0" W x 61.0" H

Bradford White

• External digital thermostatic control with LED display (+/1 degree accuracy)
• Most advanced self-modulation, adjust power to meet hot water demand
• Durable Copper immersion two heating elements, field Serviceable. Flow Rate- up to 4.4 GPM
• Simple installation – bottom 3/4 inch NPT water connections
• Threaded for easy replacement, simple installation, digital temperature display

Rheem

• Bradford White ICON System
• Advanced ScreenLok Technology Flame Arrestor Design
• Resettable Thermal Switch
• Maintenance-Fre
• Factory-Installed Hydrojet Total Performance System

Bradford White

• Modulates heat output in response to the flow rate of water running through the unit.
• Power vented directly vertically (rooftop) or sideways (wall) via Stainless Steel CAT III Flue 3.5" Diameter Included (20")
• NATURAL GAS - European Model - Digital Display is in Celsius
• Delivers 6.6 gpm of hot water with a 35°F Instant Temperature Rise (Equivalent to 5.5gpm with a 45F temp Rise)
• Certified for Installation in Manufactured (Mobile) Homes Pure Copper Heat Exchanger

GASFLEX

• Protective magnesium anode rod provides added protection against corrosion for long trouble free service
• The package length of the product is 30 inches
• The package width of the product is 30 inches
• The package height of the product is 60 inches

Bradford White

• Whole home indoor, gas powered tankless water heater, rated at 3 GPM that activates only on demand and no pilot light needed, reducing energy consumption
• Sleek, modern design with black tempered glass front panel featuring an easy to use LED display controls
• Features fully automatic temperature controls with an energy saving mode and child lock technology
• Safe electronic ignition system; Plugs into standard 110v electrical outlet with UL-listed cord. Field tested to 5500 ft. elevation (not recommended to be used any higher)
• Uses standard 1/2" NPT water fittings and comes with horizontal venting allowing for a convenient and quick installation

Eccotemp

• V65iN HE High Efficiency Tankless Hot Water Heater - Natural Gas: Indoor Installation Only
• Up to 6.5 GPM hot water flow rate (varies by groundwater temp)
• Control-R 2.0 mobile app features timers and schedules throughout the day and allows you to remotely put the system into vacation mode.
• Endless hot water for your entire home
• Residential Factory Warranty - 120 months (heat exchanger), 12 months (labor), 60 months (parts)

Rinnai

• Blue Diamond glass coating provides superior corrosion resistance to industry-standard glass lining
• Self-powered electronic gas valve uses thermopile to generate power needed to operate the electronic gas control without requiring external power
• Internal microprocessor provides enhanced operating parameters and tighter differentials for precise sensing and faster heating response
• Dynaclean diffuser dip tube helps reduce lime and sediment buildup, maximizes hot water output; made from long-lasting PEX cross-linked polymer
• Meets all current regulations set forth by the National Appliance Energy Conservation Act (NAECA)

A. O. Smith