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5 Best Gas Tankless Water Heaters of 2025

Last Updated - 2025/10/17

1
Best Choice
25% Off

✖
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
25% Off

RINNAI RX199iN Condensing Tankless Water Heater RX199 Features 0.96 UEF with 199k BTU.

Rinnai

CA$2,198.00

CA$2,966.00
(25% Off)

More Details
Main highlights
- Smart Sense -Gas Control System
- Smart Connect - Rinnai Central App - Setup, Service & Troubleshoot
- Quick Flush - Simplified Flushing
- One model - Indoor/Outdoor, Natural Gas/Propane
- Industry leading 2" venting up to 75 feet; Recirculation: Field convertible with Internal Pump kit; Versa Vent - Outdoor Vent Adaptor and Lime Detection
CA$2,198.00
CA$2,966.00 (25% Off)
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.

Rinnai

New Rinnai RX180iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 10 GPM, 180,000 BTU

Rinnai

CA$2,100.00

More Details
Main highlights
- Super High Efficiency (96%)
- Smart Sense -Gas Control System
- Smart Connect - Rinnai Central App - Setup, Service & Troubleshoot
- Quick Flush - Simplified Flushing
- One model - Indoor/Outdoor, Natural Gas/Propane
CA$2,100.00
3

✖
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 113,000 BTU 4.7 GPM Propane Tankless Water Heater - High Efficiency Instant Hot Water for Whole House Use, Indoor Residential on Demand Water Heater with Multi-Point Simultaneous Heating

thermomate

CA$599.99

More Details
Main highlights
- [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 propane 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 & 113,000 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.
CA$599.99
4
Best Value

✖
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.

Ranein

Ranein Natural Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater

Ranein

CA$599.00

More Details
Main highlights
- Upgrade features: Four Seasons Function: Automatically adjust the water temperature output based on the seasonal water temperature changes. Kitchen Function: Default water output temperature is 100°F, suitable for kitchen use. Bathtub Function: Adjustable water output quantity with a reminder when the set output quantity is reached, catering to various environmental needs.
- Save Money: The kit already includes the exhaust pipe, so you don't need to spend extra money on purchasing it separately. With an oxygen-free copper water tank, it reduces heat loss and lowers energy consumption. Applied with standard 1/2" NPT water fitting and gas inlet.
- Recommendation: We strongly advise that all installations of the device adhere to local building and plumbing regulations at the installation location, and should be carried out by licensed professionals. This product is not recommended for use in areas over 2,000 feet
- Performance: The on-demand tankless water heater boasts a heating capacity of 100,000 BTU and a hot water flow rate of 4.3 gallons per minute (GPM). It can provide continuous hot water for 2-3 water supply points, making it sufficient to meet the hot water needs of a household's bathroom, kitchen, and bar area.
- No Waiting Required: Unlike traditional tank water heaters, tankless water heaters eliminate the need for a 30-minute preheating wait time, allowing you to have unlimited hot water on demand.
CA$599.00
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.

thermomate

ThermoMate 113,000 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 Simultaneous Heating

thermomate

CA$639.99

More Details
Main highlights
- [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 & 113,000 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.
CA$639.99

5 Best Gas Tankless Water Heaters of 2025

RINNAI RX199iN Condensing Tankless Water Heater RX199 Features 0.96 UEF with 199k BTU.

New Rinnai RX180iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 10 GPM, 180,000 BTU

ThermoMate 113,000 BTU 4.7 GPM Propane Tankless Water Heater - High Efficiency Instant Hot Water for Whole House Use, Indoor Residential on Demand Water Heater with Multi-Point Simultaneous Heating

Ranein Natural Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater

ThermoMate 113,000 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 Simultaneous Heating

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