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Best tankless gas water heaters - Holiday Sale 2025

Last Updated - December 14, 2025

1
Best Choice

✖
Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

Rinnai

NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU

Picked by 1706 people in the last week

Rinnai

$1,532.79

More Details
Main highlights
- Smart, Efficient Design: This water heater's modern design includes an easy-to-use interface, Quick Flush feature for simplified flushing, as well as a super-high energy efficiency factor of UEF .98; See Controlr module for WiFi control (not included)
- Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to find a qualified technician to install your tankless water heater, and use the Rinnai Central App for help with setup, service & troubleshooting; We do not recommend installing a water heater without a technician
- One Model, Anywhere: This Rinnai tankless water heater is installable indoors or outdoors thanks to our new Versa Vent and powered by either propane or natural gas thanks to a Smart Sense gas control system; RX-OVC vent cap required for outdoor install
- Never Run Out of Hot Water with this Compact Tankless Gas Water Heater: This condensing propane and natural gas tankless water heater from Rinnai is only the size of a small suitcase, but provides up to 11.1 GPM (7 fixtures at once)
- Find Your Rinnai: See our product guides, manuals, energy guide, warranty information, videos, and tables to find the right tankless water heater size for your home; Check our Ground Water Temperature Map to see if this heater is optimal for your region
$1,532.79
2

✖
Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

Rheem

Rheem RTG-84DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water Heater 8.4 GPM, 180,000 BTUs

Rheem

$953.00

More Details
Main highlights
- Rheem RTG tankless gas water heaters offer high-efficiency, space-saving designs with multiple models to fit any home size, fuel type, and hot water demand.
- Powered by natural gas with 180,000 BTUs, this durable tankless unit ensures fast, reliable hot water—even during peak household demand.
- Hot-start programming prevents cold water bursts, making this tankless natural gas water heater ideal for back-to-back showers.
- High-efficiency tankless gas water heater delivers up to 8.4 GPM, perfect for 2–3 bathroom homes with multiple hot water needs like showers and laundry.
- Designed for indoor installation, this high-efficiency tankless natural gas water heater features a durable, compact metal cabinet and supports easy wall mounting by a qualified installer.
$953.00
3
Best Value
13% Off

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Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

FOGATTI
13% Off

FOGATTI Natural Gas Tankless Water Heater Indoor - Max 7.5 GPM 170,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 170S Series

FOGATTI

$639.00

$739.00
(13% Off)

More Details
Main highlights
- Trusted Quality and Support: Built with a high-efficiency copper heat exchanger and 304 stainless steel burner, this water heater offers exceptional durability and performance. Certified by CSA and equipped with multiple safety features, it meets the highest safety standards for reliable operation
- Reliable Protection and Support: The FOGATTI natural gas tankless water heater includes 2 years of full coverage for the entire unit and 5 years of coverage for the heat exchanger. Our dedicated customer support team is ready to assist with any questions or concerns, providing peace of mind for you
- Quick and Easy Installation: The compact design measuring 25 x 16.3 x 7.3 inches makes installation hassle-free. Tankless gas water heater is compatible with low water pressure from 15-150 PSI, ensuring smooth operation even in areas with weaker water pressure. Simply connect to a standard 120V AC for seamless operation
- Precision Temperature Control: With advanced water servo technology and temperature sensors, the gas tankless water heater indoor precisely adjusts water flow and gas intake to maintain a temperature difference within ±1℉. The four-stage combustion system ensures consistent comfort, whether it’s a chilly winter or a hot summer
- Powerhouse Performance: The FOGATTI tankless water heater takes up a third of the space of traditional tank heaters but delivers 5 times the performance. With a high heating power of 170,000 BTU and a flow rate of 7.5 GPM, it provides endless hot water on demand, perfect for multitasking households
- Note: Important Usage Guidelines: Tankless water heater natural gas is equipped with active heating anti-freeze device, If enviroment temp drop below 5℉ or not be used for long period, drain the water inside to prevent damage. For optimal performance, recommended for use below 2000 feet altitude
- Instant Heating: Unlike traditional tank heaters, this tankless water heater gas delivers instant and endless hot water as water flows through. Whether it’s for showers, sinks, or appliances, even for 3-5 outlet points, it ensures uninterrupted hot water whenever you need it
$639.00
$739.00 (13% Off)
4

✖
Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

thermomate

ThermoMate CZ422NG, 102,000 BTU 4.7 GPM Natural Gas Tankless Water Heater, High Efficiency Instant On-Demand Hot Water for Whole House Use, Indoor Residential Water Heater with Multi-Point Heating

thermomate

$399.99

More Details
Main highlights
- [Wind Resistant] - Engineered with a DC High-speed Fan (360Pa static pressure/3000 RPM), the system ensures powerful exhaust evacuation capable of withstanding winds from a major hurricane (Category 3 and above, >111 mph/178 km/h), eliminating safety risks like backdraft and flameouts during the most extreme weather.
- [Smart Diagnostic Display] - Equipped with a 3.5-inch LED touchscreen, it allows you to effortlessly adjust and monitor output water temperature（90°F to 140°F）while providing real-time tracking of water flow, fan operation, and flame status. Advanced error code technology enables rapid diagnosis of water heater malfunctions. The UL-certified 120V/5-foot power cord ensures continuous power supply for real-time monitoring systems.
- [Safety & Reliable] - The gas tankless water heater comes standard with a range of safety features including boil-dry burning protection, Freeze protection, Flame out protection, Overheating Protection, Over temperature protection, Timeout protection, Pipe blockage protection, High-Temperature Lock Protection, Excessive Air Pressure Protection.
- [Energy Efficient & Save Money] - The heat exchanger is constructed from high-quality oxygen-free copper, providing superior thermal conductivity and corrosion resistance compared to stainless steel. It achieves a thermal efficiency of 98% (vs. 80% for stainless steel models) and boasts a uniform energy factor (UEF) of 0.81. This design reduces energy waste, lowering annual operating costs by approximately 30% versus traditional systems.
- [Easy to Install & Save space] - The whole house tankless water heater features standard 3/4" NPT water inlet/outlet connectors, a 1/2" NPT gas inlet, a 3" OD vent, and a UL-approved 120V plug, ensuring compatibility with most households. With its compact dimensions of 21"H x 13"W x 7"D, the on-demand water heater requires less than one-third of the space occupied by traditional tank models, freeing up valuable room in your home.
- [4.7 GPM & 102,000 BTU] - The ThermoMate instant hot water heater delivers consistent hot water to 3-4 fixtures simultaneously, allowing you to have unlimited hot water on demand. No waiting time, no cold water shocks, perfect for busy households. Adopting advanced water flow sensor, the built-in chip can adjust the heating power 20,000 times per second, ensuring that the hot water within ±1℉ fluctuations for a comfortable shower experience.
$399.99
5

✖
Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

FOGATTI

FOGATTI Natural Gas Tankless Water Heater Outdoor - Max 8.1 GPM 180,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 180S Series, New Upgraded

FOGATTI

$739.00

More Details
Main highlights
- Trusted Quality and Support: Built with a high-efficiency oxygen-free copper heat exchanger and 304 stainless steel burner, this tankless water heater gas outdoor offers exceptional durability and performance. Certified by CSA and equipped with multiple safety features, it meets the highest safety standards, ensuring reliable and secure operation
- Reliable Protection and Support: FOGATTI water heater includes 2 years of full coverage for the entire unit and 5 years of coverage for the heat exchanger. Our dedicated customer support team is ready to assist with any questions or concerns, providing peace of mind for you
- Quick and Easy Installation: The compact design measuring 26.2 x 17.1 x 7.1 inches makes installation hassle-free. The gas tankless water heater is compatible with low water pressure from 15-150 PSI, ensuring smooth operation even in areas with weaker water pressure. Simply connect to a standard 120V AC for seamless operation
- Precision Temperature Control: With advanced water servo technology and temperature sensors, the tankless gas water heater precisely adjusts water flow and gas intake to maintain a temperature difference within ±1℉. The four-stage combustion system ensures consistent comfort, whether it’s a chilly winter or a hot summer
- Note: Natural gas tankless water heater is equipped with active heating anti-freeze device, If enviroment temp drop below 5℉ or not be used for long period, drain the water inside to prevent damage. For optimal performance, recommended for use below 2000 feet altitude
- Instant Hot Water: Say goodbye to preheating delays! FOGATTI tankless water heater delivers continuous hot water instantly, powered by 180,000 BTU and up to 8.1 GPM flow rate. Whether it’s for showers, sinks, or appliances, even for 3-5 outlet points, it ensures uninterrupted hot water
- Built for Outdoor Durability: Designed specifically for outdoor installation, this tankless water heater gas features a remote control panel for convenient indoor operation. The bottom-mounted fan enhances safety, durability, and lifespan by preventing smoke backflow and ensuring stable combustion, making it reliable in all seasons
$739.00

Best tankless gas water heaters - Holiday Sale 2025

NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU

Rheem RTG-84DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water Heater 8.4 GPM, 180,000 BTUs

FOGATTI Natural Gas Tankless Water Heater Indoor - Max 7.5 GPM 170,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 170S Series

ThermoMate CZ422NG, 102,000 BTU 4.7 GPM Natural Gas Tankless Water Heater, High Efficiency Instant On-Demand Hot Water for Whole House Use, Indoor Residential Water Heater with Multi-Point Heating

FOGATTI Natural Gas Tankless Water Heater Outdoor - Max 8.1 GPM 180,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 180S Series, New Upgraded

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