Choosing the right tankless unit can make a big difference in hot-water comfort, utility costs, and installation flexibility. The best models balance flow rate, BTU output, venting needs, and efficiency for your home.
Below, we focus on the top non-condensing natural gas tankless water heaters for buyers who want reliable performance without overbuying capacity or complexity.
Best 10 Non Condensing Natural Gas Tankless Water Heaters Picks for 2026
Compact Indoor Pick
Rinnai RE140iN 5.3 GPM Indoor Natural Gas
- Up to 5.3 GPM flow rate
- Compact indoor wall-mounted design
- LED display with service reminders
Best For: Indoor homes needing efficient on-demand hot water with a small footprint
Outdoor High-Flow Pick
FOGATTI 8.1 GPM Outdoor Natural Gas
- Up to 8.1 GPM output
- 180,000 BTU for multi-point use
- CSA certified with precise temperature control
Best For: Outdoor homes needing high hot-water volume and stable temperature control
Reliable Value Pick
Rinnai V53DeN 5.3 GPM Natural Gas
- Up to 5.3 GPM flow rate
- Compact outdoor space-saving design
- Energy-saving on-demand heating
Best For: Families needing a dependable outdoor tankless unit with efficient everyday use
Indoor Multi-Point Pick
ThermoMate CZ422NG 5 GPM Indoor Natural Gas
- Up to 5 GPM output
- 3.5-inch LED diagnostic display
- Eight built-in safety protections
Best For: Residential buyers wanting an indoor tankless heater with diagnostics and safety features
High-Capacity Non-Condensing Pick
Bosch 940 ES NG Tankless Water Heater
- 199,000 max input for high output
- 9.4 GPM capacity at 35°F rise
- Vertical or horizontal venting support
Best For: Larger households needing a high-capacity indoor natural gas unit
Efficient Whole-Home Value
CAMPLUX Climatech 7 Natural Gas Tankless Water Heater
- Up to 5 GPM for 2-4 fixtures
- 113,000 BTU input with on-demand heat
- 8 built-in safety protections
Best For: Moderate whole-home use with safety features and compact installation
Premium Copper Heat Exchanger Choice
Noritz NR98SVNG 7.5 GPM Indoor/Outdoor Tankless Natural Gas Water Heater
- Up to 9.8 GPM flow rate
- Commercial-grade copper heat exchanger
- Indoor/outdoor installation support
Best For: High-flow buyers wanting a premium copper exchanger and flexible placement
Outdoor High-Efficiency Pick
Rheem 7.0 GPM Outdoor NG Tankless
- 7.0 GPM for 2–3 bathroom homes
- 160,000 BTUs with hot-start programming
- Outdoor wall mount with freeze protection
Best For: Families wanting a compact outdoor gas unit for moderate whole-home demand
High-Capacity Smart Option
- Up to 9.5 GPM for larger homes
- EcoNet Smart Monitoring system
- Outdoor mount with stainless steel build
Best For: Busy homes needing high hot-water capacity and smart monitoring
Budget-Friendly Outdoor Performer
- Up to 8.5 GPM for 4–6 outlet points
- Outdoor wall mount with anti-freeze protection
- Blower design helps reduce smoke backflow
Best For: Households wanting strong outdoor performance without extra smart features
Compact Indoor Pick – Rinnai RE140iN 5.3 GPM Indoor Natural Gas
If you want one of the more space-saving non condensing natural gas tankless water heaters for indoor use, the Rinnai RE140iN is built around efficient on-demand heating and a compact wall-mounted footprint. It delivers up to 5.3 GPM, supports multiple fixtures, and includes an LED display with service reminders and error codes to help with basic monitoring.
Best For: Homes that want a compact indoor tankless unit with strong flow capacity and energy-saving on-demand operation.
Pros:
- Up to 5.3 GPM for serving multiple fixtures at once
- Heats only when needed to conserve energy
- LED screen shows service reminders and error codes
- Compact wall-mounted design saves space
Cons:
- Professional installation is recommended
- WiFi control requires a separate Controlr module
- Indoor installation only
Overall, this Rinnai model is a practical choice if your priority is reliable hot water in a compact indoor setup. Its feature set is focused on efficiency, serviceability, and everyday whole-home use rather than extra smart-home extras.
Outdoor High-Flow Pick – FOGATTI 8.1 GPM Outdoor Natural Gas
The FOGATTI is a strong fit if you need one of the higher-capacity non condensing natural gas tankless water heaters for outdoor installation. With up to 8.1 GPM and 180,000 BTU, it is designed to supply multiple outlets and uses water servo precision plus temperature sensors to hold temperatures steady.
Best For: Outdoor whole-house setups that need high flow, precise temperature control, and low-pressure compatibility.
Pros:
- Up to 8.1 GPM and 180,000 BTU for multiple outlets
- Water servo technology helps maintain steady temperatures
- CSA certified with multiple safety features
- Works with 15-150 PSI water pressure
Cons:
- Outdoor installation only
- Recommended for use below 2000 feet altitude
- Drain the unit if temperatures fall below 5°F during inactivity
This FOGATTI model stands out for capacity and control, especially if your home needs reliable outdoor hot water delivery to several points. Its durability and warranty coverage make it a sensible option for buyers who want performance and protection in one package.
Reliable Value Pick – Rinnai V53DeN 5.3 GPM Natural Gas
The Rinnai V53DeN is a straightforward non condensing natural gas tankless water heater for buyers who want dependable on-demand hot water without a bulky tank. It delivers up to 5.3 GPM, heats only when needed to conserve energy, and uses a compact outdoor design that fits easily in tighter spaces.
Best For: Families wanting a space-saving outdoor unit with dependable flow and efficient operation.
Pros:
- Up to 5.3 GPM for serving multiple appliances
- Heats water only when needed to save energy
- Compact outdoor design for tight spaces
- 10-year heat exchanger warranty noted in the product details
Cons:
- Professional installation is recommended
- Outdoor installation only
- No built-in smart controls mentioned
For shoppers who want a simple, space-saving tankless option from a known brand, this model covers the essentials well. It focuses on efficient hot water delivery and long-term durability rather than extra features.
Indoor Multi-Point Pick – ThermoMate CZ422NG 5 GPM Indoor Natural Gas
The ThermoMate CZ422NG is an indoor option among non condensing natural gas tankless water heaters, built for steady whole-home hot water with a 5 GPM rating and 113,000 BTU output. It includes smart diagnostics, a digital display, and multiple built-in protections that make it easier to monitor and operate in a residential setup.
Best For: Households that want an indoor multi-point unit with diagnostic features and strong built-in safety protections.
Pros:
- Up to 5 GPM for two showers at the same time
- 3.5-inch LED display with error codes and status monitoring
- Eight protection features for safer operation
- Compact indoor wall-mounted design saves space
Cons:
- Indoor installation only
- Lower flow rate than larger whole-house models
- Best results depend on proper venting and installation setup
This ThermoMate unit is a solid choice when you want a compact indoor tankless heater with practical controls and strong safety coverage. It is best suited to homes that value consistency, visibility, and space efficiency over maximum output.
High-Capacity Non-Condensing Pick – Bosch 940 ES NG Tankless Water Heater
If you want one of the most powerful non condensing natural gas tankless water heaters, the Bosch 940 ES NG is built for high-demand homes that need strong hot-water delivery. Its 199,000 BTU max input and 9.4 GPM capacity make it a practical choice when you want a non-condensing unit with serious output and flexible venting.
Best For: Larger households that want a high-capacity natural gas tankless unit with horizontal or vertical venting options.
Pros:
- 199,000 max input supports strong whole-home performance
- 9.4 GPM capacity at a 35°F rise
- Can vent vertically or horizontally with 3″ or 4″ stainless steel
- Electronic ignition and patented burner design
Cons:
- Indoor installation only
- Non-condensing design may not suit buyers prioritizing condensing-efficiency models
- Requires proper venting setup
The Bosch 940 ES NG stands out for capacity and installation flexibility, making it a strong fit if output matters more than compact simplicity. Among non condensing natural gas tankless water heaters, it is aimed at buyers who need a robust, proven high-capacity option.
Efficient Whole-Home Value – CAMPLUX Climatech 7 Natural Gas Tankless Water Heater
The CAMPLUX Climatech 7 is a compact option for buyers comparing non condensing natural gas tankless water heaters for whole-house use. With up to 5 GPM, 113,000 BTU input, and multi-point heating, it is designed to deliver steady hot water to several fixtures while keeping the unit space-saving and feature-rich.
Best For: Homes that want an indoor natural gas tankless heater with strong safety features and moderate whole-house capacity.
Pros:
- Up to 5 GPM for 2-4 fixtures simultaneously
- 113,000 BTU input with on-demand hot water
- 8 safety protections, including freeze and boil-dry protection
- 3.5-inch LED display with adjustable 90-140°F temperature range
Cons:
- Lower flow rate than higher-capacity models
- Indoor installation only
- Requires 120V power and venting setup
This model is a good fit if you want a newer-featured unit with practical protections, easy status monitoring, and a smaller footprint. It is especially appealing for buyers who value balanced performance rather than maximum output.
Premium Copper Heat Exchanger Choice – Noritz NR98SVNG 7.5 GPM Indoor/Outdoor Tankless Natural Gas Water Heater
The Noritz NR98SVNG is a premium option in the non condensing natural gas tankless water heaters category if you want high flow and flexible installation. With flow rates up to 9.8 GPM, a commercial-grade copper heat exchanger, and indoor/outdoor compatibility, it is designed for buyers who want a durable, high-capacity system.
Best For: Buyers who want a high-flow natural gas tankless heater with indoor/outdoor installation flexibility and a copper heat exchanger.
Pros:
- Flow rates up to 9.8 GPM
- Commercial-grade copper heat exchanger with thicker piping
- Indoor/outdoor installation compatibility
- Includes remote thermostat and 6′ power cord
Cons:
- Heavier unit at 54 pounds
- Requires proper installation and venting planning
- Higher-capacity system may be more than needed for smaller homes
If you want a tankless heater with strong flow potential and flexible placement, the Noritz is a compelling choice. Its copper heat exchanger and included accessories make it especially suited to buyers looking for a more premium build.
Outdoor High-Efficiency Pick – Rheem 7.0 GPM Outdoor NG Tankless
If you’re comparing non condensing natural gas tankless water heaters for a smaller whole-home setup, this Rheem model is built around steady output and simple outdoor placement. It delivers up to 7.0 GPM and 160,000 BTUs, which makes it a practical fit for 2–3 bathroom homes with overlapping hot water demand.
Best For: 2–3 bathroom homes that want a space-saving outdoor unit with reliable everyday hot water.
Pros:
- Up to 7.0 GPM supports multiple hot water uses at once.
- 160,000 BTUs and hot-start programming help reduce cold-water bursts.
- Outdoor wall-mount design saves indoor space.
- Includes self-diagnostic program, freeze protection, and low activation flow rate.
Cons:
- Requires qualified installation.
- Designed for outdoor mounting only.
- Lower capacity than larger 8.5–9.5 GPM options.
This is a straightforward non-condensing choice if you want a compact, high-efficiency gas unit for everyday family use. The combination of outdoor installation, hot-start programming, and multiple convenience features makes it appealing for buyers prioritizing dependable performance over maximum capacity.
High-Capacity Smart Option – Rheem 9.5 GPM Ultra Low NOx
Among non condensing natural gas tankless water heaters, this Rheem stands out for households that need more capacity and smart monitoring. With up to 9.5 GPM, 199,900 BTUs, and outdoor mounting, it is aimed at larger homes that want strong hot water delivery and added system oversight.
Best For: Larger households or high-demand homes that want a high-capacity outdoor unit with smart monitoring.
Pros:
- Up to 9.5 GPM supports bigger household demand.
- 199,900 BTUs and outdoor mount design suit whole-house use.
- EcoNet Smart Monitoring adds protection, comfort, and energy-saving visibility.
- Built with copper and stainless steel for rugged durability.
Cons:
- Requires 120-volt power and electronic ignition setup.
- More complex than basic non-smart models.
- Likely more capacity than smaller homes need.
This model makes sense if your priority is hot water volume rather than a simple basic install. The higher flow rate and smart monitoring features give it an edge for busy households, while the outdoor build keeps installation out of the way.
Budget-Friendly Outdoor Performer – Ranein 8.5 GPM Outdoor NG
Ranein Natural Gas Tankless Water Heater, Outdoor Max 8.5 GPM, 190,000 BTU Instant Hot Water Heater
Check Price On AmazonIf you want non condensing natural gas tankless water heaters with solid output and a simpler feature set, this Ranein model is worth a look. It delivers up to 8.5 GPM and 190,000 BTUs, making it suitable for 4–6 outlet points while keeping the unit compact for outdoor wall installation.
Best For: Families wanting a compact outdoor heater with strong flow for multiple fixtures.
Pros:
- Up to 8.5 GPM and 190,000 BTUs support whole-family use.
- Outdoor wall-mount design saves interior space.
- Blower under the unit is designed to reduce smoke backflow and improve combustion.
- Anti-freeze protection adds cold-weather peace of mind.
Cons:
- Not recommended for areas over 2,000 feet.
- Requires 120-volt power.
- No advanced smart-monitoring features listed.
For shoppers focused on output and outdoor convenience, this Ranein is a practical middle ground. It offers strong flow for multiple points of use, along with safety-minded airflow design and freeze protection, but it is less feature-rich than premium smart models.
How We Picked the Best Non Condensing Natural Gas Tankless Water Heaters
We prioritized models that offer strong real-world flow rates, dependable ignition and burner performance, sensible sizing for typical household demand, and clear installation options. We also looked at whether each unit is better suited to indoor or outdoor use, since venting and placement can affect both cost and convenience.
For Non Condensing Natural Gas Tankless Water Heaters, the best value is usually a model that matches your peak hot-water demand without forcing you into an oversized, inefficient setup.
Quick Comparison
Start with your household peak demand: one bathroom and light kitchen use may only need a midrange unit, while larger homes with multiple showers running at once should look at higher BTU and GPM ratings. Outdoor models can simplify installation, while indoor units may offer more placement flexibility if you already have the right venting path.
Key Buying Factors for Non Condensing Natural Gas Tankless Water Heaters
Flow Rate and BTU Output
GPM is the most important spec for everyday use, but it should be read alongside BTU rating. Higher BTU output helps maintain temperature when multiple fixtures are open or when incoming water is cold.
Installation Location
Indoor units usually require venting and more planning, while outdoor units reduce venting complexity but need weather-appropriate placement. Make sure the unit you choose fits your home’s layout and local code requirements.
Fuel Efficiency and Operating Cost
Non-condensing models are generally less efficient than condensing units, but they can still be a smart choice if you value lower upfront cost, simpler maintenance, or a proven design. The key is buying only as much capacity as you need.
Household Size and Water Habits
A smaller household with staggered usage can often choose a lower-capacity unit, while larger families should lean toward higher flow rates and stronger recovery under simultaneous demand. Think about showers, laundry, and dishwasher use happening at the same time.
Who Should Buy Which Non Condensing Natural Gas Tankless Water Heaters?
If you want a straightforward replacement or a budget-conscious upgrade, a midrange non-condensing natural gas tankless water heater is often the best fit. If you have a larger home, frequent simultaneous hot-water use, or longer plumbing runs, choose a higher-output model with enough margin for comfort.
If installation simplicity matters most, consider an outdoor unit. If your home layout favors indoor placement and you already have venting options, an indoor model may give you more flexibility. Either way, match the unit to your real demand rather than chasing the highest number on the spec sheet.
