When it comes to indoor natural gas tankless water heaters, you’re looking for a balance of high flow rate, energy efficiency, and reliability. These heaters are ideal for providing endless hot water, and natural gas models tend to offer higher GPM (gallons per minute), making them perfect for larger households or homes with multiple fixtures running simultaneously.
Here are the best indoor natural gas tankless water heaters, tailored to different household sizes and hot water demands.
Top 4 Best Indoor Natural Gas Tankless Water Heaters
| Heater Name | Max GPM | Efficiency (%) | Best For | Price Range |
|---|---|---|---|---|
| Rinnai RUR199iN | 11 GPM | 96% (Condensing) | Large homes, recirculation, multiple bathrooms | $$$$$ |
| Noritz NRC66DV | 6.6 GPM | 93% (Condensing) | Medium homes, cold climates | $$$ |
| Takagi T-H3-DV-N | 10 GPM | 95% (Condensing) | Large homes, high-demand applications | $$$$ |
| Rheem RTGH-95DVLN | 9.5 GPM | 94% (Condensing) | Energy-efficient, large homes | $$$$ |
1. Rinnai RUR199iN – Best Overall Indoor Natural Gas Tankless Water Heater
The Rinnai RUR199iN stands out for its high flow rate, built-in recirculation pump, and top-tier energy efficiency. It’s designed to handle large homes with multiple bathrooms and high hot water demand.
Key Features:
- Max GPM: Delivers up to 11 GPM, enough to run 4+ fixtures (showers, sinks, and appliances) simultaneously.
- Efficiency: 96% thermal efficiency with condensing technology that recycles exhaust heat, reducing energy costs.
- Built-in Recirculation Pump: The integrated recirculation system minimizes hot water wait time, ensuring instant hot water even at distant fixtures.
- Wi-Fi Compatibility: Works with Rinnai’s Control-R™ module, allowing you to control and monitor the heater remotely from your smartphone.
- Dual Venting Options: Includes concentric and twin-pipe venting options, providing installation flexibility.
Best For:
- Large households with multiple bathrooms or high hot water usage.
- Homes needing instant hot water throughout the house, thanks to the recirculation system.
- Homeowners looking for premium energy efficiency and Wi-Fi control.
Pros:
- High GPM—can handle multiple showers and appliances running at once.
- Built-in recirculation pump ensures hot water is delivered quickly.
- Wi-Fi compatible for easy scheduling and monitoring.
- Energy-efficient with a 96% efficiency rating, saving on utility bills.
Cons:
- Higher upfront cost, though long-term energy savings justify the expense.
- Requires professional installation due to gas and venting complexity.
2. Noritz NRC66DV – Best for Medium Homes and Cold Climates
The Noritz NRC66DV is an excellent choice for medium-sized homes or smaller families with moderate hot water demand. Its condensing technology ensures energy efficiency, while its 6.6 GPM capacity can handle multiple fixtures in warmer climates or point-of-use applications in colder regions.
Key Features:
- Max GPM: Delivers up to 6.6 GPM, suitable for 2-3 fixtures running simultaneously.
- Efficiency: 93% thermal efficiency thanks to condensing technology, reducing energy consumption and improving performance in cold climates.
- Durable Heat Exchanger: Made with stainless steel, the heat exchanger ensures long-term reliability and resistance to corrosion.
- Low NOx Emissions: Complies with low-NOx standards, making it an environmentally friendly choice.
- Compact Design: Ideal for small to medium homes where space is limited.
Best For:
- Medium-sized homes or smaller families that need hot water for 2-3 fixtures at a time.
- Homes in cold climates where hot water demand is slightly higher due to low incoming water temperatures.
- Eco-conscious households looking for a low-emission unit.
Pros:
- Durable stainless steel heat exchanger for long-lasting use.
- Condensing technology improves energy efficiency.
- Low NOx emissions make it an eco-friendly option.
- Compact design for easy installation in tight spaces.
Cons:
- Lower GPM than higher-end models, limiting the number of fixtures it can support simultaneously in cold climates.
- May need to be paired with a recirculation system if instant hot water is required.
3. Takagi T-H3-DV-N – Best for Large Homes with High-Demand
The Takagi T-H3-DV-N is a high-performance natural gas tankless water heater designed for large homes or high-demand applications. It offers 10 GPM, making it perfect for homes with multiple showers or high simultaneous water usage.
Key Features:
- Max GPM: Delivers up to 10 GPM, suitable for 3-4 bathrooms running at once.
- Efficiency: 95% efficiency with condensing technology, ensuring low energy consumption even when heating large volumes of water.
- Safety Features: Includes overheat protection, freeze protection, and anti-scald technology, ensuring safe and reliable operation.
- Durable Design: Features a stainless steel heat exchanger for long-term use and durability.
- Low-NOx Compliant: Meets emission standards for low NOx levels, making it environmentally friendly.
Best For:
- Large households with high hot water demand where multiple showers and appliances are used simultaneously.
- Homes that prioritize energy savings and durability.
- People looking for top-tier performance in both warm and cold climates.
Pros:
- High flow rate—handles multiple fixtures with ease.
- Energy-efficient with condensing technology.
- Durable heat exchanger built for long-term use.
- Includes advanced safety features like freeze and overheat protection.
Cons:
- High upfront cost, though justified by the performance and energy savings.
- Requires professional installation and proper venting.
4. Rheem RTGH-95DVLN – Best for Energy Efficiency
The Rheem RTGH-95DVLN is known for its energy efficiency and ability to handle large homes with multiple bathrooms. With 9.5 GPM, it’s more than capable of running 3-4 showers simultaneously, while its 94% efficiency ensures low energy consumption.
Key Features:
- Max GPM: Delivers 9.5 GPM, enough to support 3-4 showers at once.
- Efficiency: 94% efficiency with condensing technology to reduce energy costs.
- Recirculation Ready: Can be paired with a recirculation pump for instant hot water.
- Low NOx Emissions: Complies with emission standards for low NOx, making it environmentally friendly.
- Durable Components: Features a stainless steel heat exchanger for long-lasting performance.
Best For:
- Large homes with 3-4 bathrooms that need a high flow rate and energy savings.
- Homes looking to pair the unit with a recirculation pump for instant hot water.
- Energy-conscious homeowners wanting to reduce utility bills with a highly efficient unit.
Pros:
- High GPM—can handle large homes with multiple bathrooms.
- Condensing technology improves energy efficiency.
- Compatible with recirculation systems for instant hot water.
- Durable design with a stainless steel heat exchanger.
Cons:
- Recirculation pump sold separately.
- Requires professional installation for optimal performance.
Key Factors to Consider When Choosing an Indoor Natural Gas Tankless Water Heater
1. Flow Rate (GPM)
- For large homes, you’ll need at least 9-11 GPM to support multiple showers and fixtures running simultaneously.
- Medium homes with fewer occupants or bathrooms can typically manage with 6-7 GPM.
2. Energy Efficiency
- Look for condensing models that have 90%+ efficiency. These units use the heat from exhaust gases to preheat the incoming water, reducing energy waste and lowering your bills.
- Non-condensing models are slightly less efficient but tend to be cheaper upfront.
3. Recirculation System
- If you want instant hot water at all fixtures, consider a model with a built-in recirculation pump, like the Rinnai RUR199iN.
- Some models can be paired with external recirculation systems to reduce water waste and waiting time.
4. Climate
- Colder climates require more heating power since the incoming water temperature is lower. High GPM models (like Takagi T-H3-DV-N or Rinnai RUR199iN) ensure that the water is heated quickly and efficiently.
5. Installation Requirements
- Natural gas units require venting. Look for models with flexible venting options (like the Rinnai RUR199iN) to ensure proper installation in your home’s layout.
- Consider professional installation to ensure gas lines and venting are installed safely and to code.
Pros and Cons of Indoor Natural Gas Tankless Water Heaters
| Pros | Cons |
|---|---|
| Endless hot water—never run out | Higher upfront cost compared to electric heaters |
| Energy-efficient—saves on gas bills | Requires venting and professional installation |
| High flow rates—ideal for large homes | Complex installation, especially with recirculation systems |
| Compact design—saves space | May require gas line upgrades in older homes |
Conclusion: Which Indoor Natural Gas Tankless Water Heater is Right for You?
- For best overall performance, the Rinnai RUR199iN offers high flow rates, recirculation, and top-tier efficiency, making it ideal for large homes with multiple bathrooms.
- If you’re looking for a cost-effective option for a medium-sized home, the Noritz NRC66DV is a great choice with excellent efficiency and performance.
- For high-demand households, the Takagi T-H3-DV-N provides 10 GPM, making it perfect for homes needing top-tier performance.
- If energy efficiency is your priority, the Rheem RTGH-95DVLN offers 9.5 GPM with impressive energy savings, perfect for large homes.
Each of these models offers endless hot water, energy savings, and reliable performance to meet your household’s hot water demands!