Bosch 940 ES NG Tankless Water Heater Alternatives: 6 Similar Picks Compared
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The Bosch 940 ES NG tankless water heater delivers high flow rates for large households. If you need bosch 940 es ng tankless water heater alternatives, this guide helps you compare options. The original unit provides 9.4 GPM at a 35°F rise with 199,000 BTU input. It vents vertically or horizontally using 3-inch or 4-inch stainless steel pipes. Its dimensions are 31 x 18 x 12 inches and it weighs 76 pounds. Some buyers might prefer different flow rates, compact sizes, or outdoor-rated models. Others may want smart controls or specific installation locations. We selected these alternatives because their specifications overlap with the Bosch 940 ES NG. This list includes natural gas units with varying GPM outputs and physical footprints. You will find indoor and outdoor options with distinct feature sets. Each pick matches the core requirement of on-demand hot water. The comparison focuses on practical specs like BTU capacity and dimensions. This approach helps you find a unit that fits your specific plumbing constraints. You can choose based on flow needs or venting flexibility rather than brand loyalty.
Our top pick: Bosch 9.4 GPM Natural Gas Tankless Water Heater.
Comparing Bosch 940 Alternatives
Rheem IKONIC 10.1 GPM Natural Gas Tankless Water Heater
The Rheem IKONIC offers a higher flow rate of 10.1 GPM compared to the Bosch 9.4 GPM. It includes Wi-Fi connectivity for smart control, which the Bosch lacks. The Rheem is slightly taller and deeper, measuring 28.6 inches high and 13.7 inches deep. It weighs 86 pounds, making it heavier than the Bosch at 76 pounds. This model suits large families needing maximum hot water volume and remote monitoring. If you prioritize smart features and peak flow over the Bosch’s specific venting options, this is the stronger choice.
Noritz 7.5 GPM Outdoor Natural Gas Water Heater
The Noritz NR98-OD is designed for outdoor installation, unlike the Bosch which is typically indoor. It provides 7.5 GPM, which is lower than the Bosch’s 9.4 GPM. This unit is vent-free, simplifying installation for outdoor spaces. It is beige, whereas the Bosch is gray. The Noritz trades raw flow capacity for outdoor versatility and efficiency. Choose this if you need a dedicated outdoor solution and can accept a lower flow rate. It fits users who value easy outdoor placement over the maximum hot water output provided by the Bosch 940 ES NG.
Bosch Natural Gas Tankless Water Heater
The Bosch 830 ES NG delivers 8.3 GPM, which is lower than the 940 ES NG’s 9.4 GPM. It shares the same brand and natural gas fuel type. The 830 model is slightly smaller, measuring 30.5 inches high and 11.3 inches deep. It weighs 80 pounds, similar to the 940. This unit is ideal for households that need reliable high-flow performance but do not require the absolute maximum capacity. It offers flexible venting options similar to the 940. Select this if you prefer a slightly more compact unit with strong, consistent heating for large homes.
Reliance 199,000 BTU Gas Tankless Water Heater
The Reliance X3-199 matches the Bosch’s 199,000 BTU input but is significantly smaller and lighter. It weighs only 8.5 pounds compared to the Bosch’s 76 pounds. Its dimensions are 18 inches high and 11 inches wide, making it much more compact. This unit focuses on raw heat output in a small package. It lacks the high flow rate of the Bosch, which provides 9.4 GPM. Choose this if you have space constraints and need intense heating capacity. It suits users prioritizing compact size and BTU power over high-volume water delivery.
Ranein 4.3 GPM Indoor Natural Gas Tankless Water Heater
The Ranein RH10K provides 4.3 GPM, which is much lower than the Bosch’s 9.4 GPM. It is designed for indoor use with a copper heat exchanger for durability. The unit is gray and measures 25.6 inches high. It is intended for medium-sized homes with multi-fixture demands. This model gives up high flow capacity for reliable, steady performance in smaller applications. Pick this if you need a durable indoor unit for a household with moderate hot water needs. It is not suitable for large families requiring the high flow rates of the Bosch 940 ES NG.
VEVOR 4.3 Gal Natural Gas Tankless Water Heater
The VEVOR JSQ30-A is a 4.3-gallon capacity unit, distinct from the Bosch’s continuous flow design. It offers precise temperature control for indoor whole-house use. The unit is silver gray and weighs 19.8 pounds, much lighter than the Bosch. It measures 21.7 inches high. This model fits small to medium households needing reliable instant hot water with precise temp management. It sacrifices the high flow rate of the Bosch for compactness and temperature precision. Choose this if you prioritize exact temperature settings and a smaller footprint over the high-volume output of the Bosch 940 ES NG.
Quick picks
Our 7 picks
Bosch 9.4 GPM Natural Gas Tankless Water Heater
Best for: High-flow natural gas households
- Fuel Type
- Natural Gas
- Flow Rate
- 9.4 GPM at 35F rise
- BTU
- 199,000 BTU/hr max input
- Dimensions
- 31 x 18 x 12 in
- Weight
- 76 pounds
View on Amazon: Bosch 9.4 GPM Natural Gas Tankless Water Heater Affiliate link
The Bosch 940 ES NG delivers 9.4 GPM at a 35F rise with 199,000 BTU input. It is a non-condensing unit that vents vertically or horizontally using 3 or 4 inch stainless steel pipes. This model suits households needing high flow rates for multiple simultaneous uses. Its compact 31 by 18 by 12 inch footprint fits standard utility spaces. It operates on natural gas for consistent performance.
Pros
- 9.4 GPM flow rate at 35F rise
- 199,000 BTU max input for high capacity
- Flexible vertical or horizontal venting options
- Electronic ignition with patented burner design
Cons
- 76 pounds weight requires sturdy mounting
- Non-condensing design may be less efficient than condensing models
- Limited to natural gas fuel type only
Good fit if
- You need high flow for multiple bathrooms
- You want flexible venting directions
- You have natural gas available
Skip if
- You require propane compatibility
- You need a condensing unit for maximum efficiency
- You have limited wall space for a 31 inch height
Verdict: Bosch 940 ES NG Natural Gas offers robust 9.4 GPM output for large households. It fits users who prioritize flow rate and venting flexibility over condensing efficiency.
Rheem IKONIC 10.1 GPM Natural Gas Tankless Water Heater
Best for: High-flow indoor households with Wi-Fi needs
- Fuel Type
- Natural Gas
- Flow Rate
- 10.1 GPM
- BTU
- 180,000 BTUs
- Installation Location
- Indoor
- Dimensions
- 28.6 x 17.3 x 13.7 inches
- Features
- WiFi
View on Amazon: Rheem IKONIC 10.1 GPM Natural Gas Tankless Water Heater Affiliate link
The Rheem IKONIC RECTGH-SR10iN delivers 10.1 GPM at 180,000 BTUs for whole-house hot water. Its built-in recirculation saves water, while EcoNet Wi-Fi lets you control settings remotely. This indoor unit measures 28.6 by 17.3 by 13.7 inches. It suits large families needing high flow and smart monitoring capabilities for their natural gas heating system.
Pros
- 10.1 GPM flow rate for multiple simultaneous uses
- 180,000 BTU input for high efficiency
- Built-in EcoNet Wi-Fi for remote control
- Hot-start programming prevents cold water bursts
Cons
- Indoor installation only without conversion kit
- 86-pound weight requires sturdy mounting
- No outdoor installation capability out of the box
Good fit if
- You need high flow for large households
- You want remote monitoring via Wi-Fi
- You have indoor space for a 10.1 GPM unit
Skip if
- You require outdoor installation without modifications
- You prefer a smaller footprint under 14 inches wide
- You do not need recirculation features
Verdict: Rheem IKONIC 10.1 GPM Natural Gas fits homes needing robust flow and smart controls. It works well for large families with high hot water demands.
Noritz 7.5 GPM Outdoor Natural Gas Water Heater
Best for: outdoor vent-free installations
- Fuel Type
- Natural Gas
- Flow Rate
- 7.5 GPM
- BTU
- 199,000 BTU
- Installation Location
- Outdoor
View on Amazon: Noritz 7.5 GPM Outdoor Natural Gas Water Heater Affiliate link
The Noritz NR98-OD NG is a natural gas tankless water heater designed strictly for outdoor installation. It delivers 7.5 GPM with 199,000 BTU input and 84% thermal efficiency. You do not need venting for this unit. It features a low 0.05 GPM activation flow rate and an onboard diagnostic system. This model suits you if you need a durable, weather-ready solution without complex ductwork.
Pros
- 199,000 BTU heating power
- 7.5 GPM flow rate
- 84% thermal efficiency
- No venting required
- Self-diagnostic computer system
Cons
- Outdoor installation only
- 7.5 GPM capacity is lower than some indoor competitors
- Beige color may not blend with all exteriors
Good fit if
- You need a tankless heater for outdoor use
- You want to avoid venting installation
- You require high thermal efficiency
Skip if
- You need an indoor installation
- You require more than 7.5 GPM flow
- You prefer natural gas alternatives with higher flow rates
Verdict: Noritz NR98-OD 7.5 GPM Outdoor Heater is a solid choice for homeowners needing a vent-free outdoor solution. It fits you if you prioritize efficiency and easy installation over maximum flow rate.
Bosch Natural Gas Tankless Water Heater
Best for: High-flow natural gas installations
- Fuel Type
- Natural Gas
- Flow Rate
- 8.3 GPM at 35F rise
- BTU
- 175,000 BTU/hr max input
- Dimensions
- 30.5 x 17.9 x 11.3 in
- Weight
- 80 pounds
View on Amazon: Bosch Natural Gas Tankless Water Heater Affiliate link
The Bosch 830 ES NG is a natural gas tankless water heater with a maximum input of 175,000 BTU. It delivers 8.3 gallons per minute at a 35-degree temperature rise. The unit features 83% thermal efficiency and electronic ignition. You can vent it vertically or horizontally using 3-inch or 4-inch stainless steel pipes. Its compact dimensions are 30.5 by 17.9 by 11.3 inches. This model suits homes needing high flow rates with flexible venting options.
Pros
- 175,000 BTU/hr max input for strong heating power
- 8.3 GPM flow rate at 35F rise
- 83%+ thermal efficiency rating
- Flexible vertical or horizontal venting with 3" or 4" pipe
Cons
- Heavier build at 80 pounds compared to lighter indoor units
- Lacks digital display for precise temperature readouts
- Natural gas only, not compatible with propane without conversion
Good fit if
- You need a high flow rate for multiple bathrooms
- You require flexible venting options for your installation
- You want a high-efficiency natural gas unit
Skip if
- You need a propane-compatible heater
- You prefer a lightweight unit for easy mounting
- You want digital temperature controls
Verdict: Bosch 830 ES NG 8.3 GPM Gas Heater provides reliable high-flow performance for large households. It fits buyers who need flexible venting and strong heating capacity.
Reliance 199,000 BTU Gas Tankless Water Heater
Best for: high-output needs in compact spaces
- Fuel Type
- Natural Gas, Propane
- BTU
- 199,000 BTU
- Installation Location
- Indoor/Outdoor
- Dimensions
- 11 x 11 x 18 inches
- Weight
- 8.5 pounds
View on Amazon: Reliance 199,000 BTU Gas Tankless Water Heater Affiliate link
The Reliance X3-199 delivers 199,000 BTU of heating power with a compact 11x11x18 inch footprint. It features X3 Scale Prevention Technology to extend heat exchanger life and offers field conversion between natural gas and propane. You get a digital display for dual recirculation scheduling and remote control capability. This unit suits homes needing high output in a small space with versatile installation options.
Pros
- 199,000 BTU output for high demand
- X3 Scale Prevention Technology protects the heat exchanger
- Field convertible between natural gas and propane
- Built-in digital display with dual recirculation programming
Cons
- Higher BTU output may be excessive for small households
- Compact size limits simultaneous flow rate compared to larger units
- Data does not mention a built-in Wi-Fi module for smart home integration
Good fit if
- You need maximum heating power in a tight space
- You want flexibility to switch between gas fuels
- You prefer manual digital control over app-based management
Skip if
- You require a high flow rate for multiple bathrooms
- You need a unit with integrated smart home connectivity
- You are looking for a budget-friendly entry-level model
Verdict: Reliance X3-199 199k BTU Gas Heater provides intense heat in a small package for homes with high hot water demands. It fits users who prioritize raw BTU output and fuel flexibility over high flow rates or smart features.
Ranein 4.3 GPM Indoor Natural Gas Tankless Water Heater
Best for: Indoor multi-fixture households
- Fuel Type
- Natural Gas
- Flow Rate
- 4.3 GPM
- BTU
- 100,000 BTU
- Installation Location
- Indoor
- Temperature Control
- 95°F-155°F
- Dimensions
- 25.6 x 16.9 x 16.9 inches
View on Amazon: Ranein 4.3 GPM Indoor Natural Gas Tankless Water Heater Affiliate link
The Ranein 4.3 GPM model delivers 100,000 BTU of heating power for indoor use. It supports simultaneous use at three to four water points. The unit features an oxygen-free copper heat exchanger and precise temperature control between 95°F and 155°F. It includes four preset modes and anti-freeze protection down to 14°F. This heater suits households needing steady hot water without the bulk of a tank.
Pros
- 100,000 BTU heating capacity
- 4.3 GPM flow rate
- Oxygen-free copper heat exchanger
- Four intelligent preset modes
- Anti-freeze protection to 14°F
Cons
- Indoor installation only
- Not suitable for elevations above 2,000 feet
- No outdoor weatherproofing
Good fit if
- You need hot water for three to four fixtures
- You want precise temperature control between 95°F and 155°F
- You require anti-freeze protection for cold climates
Skip if
- You live above 2,000 feet elevation
- You need an outdoor-rated unit
- You require flow rates higher than 4.3 GPM
Verdict: Ranein 4.3 GPM Natural Gas Indoor Heater provides reliable on-demand heating for medium-sized homes. It fits buyers who prioritize copper durability and multi-point flow over outdoor versatility.
VEVOR 4.3 Gal Natural Gas Tankless Water Heater
Best for: Indoor whole house use with precise temp control
- Fuel Type
- Gas
- BTU
- 100,000 BTU/hr
- Installation Location
- Indoor
- Capacity
- 4.3 Gal
- Temperature Control
- ±1°F
- Dimensions
- 21.7 x 13.8 x 13.8 inches
View on Amazon: VEVOR 4.3 Gal Natural Gas Tankless Water Heater Affiliate link
The VEVOR 4.3 Gal unit delivers 100,000 BTU/hr of heating power for indoor natural gas use. It features smart temperature control that maintains water within ±1°F of your setting. The device includes a large LED display and touch panel for easy monitoring. It weighs 19.8 pounds and measures 21.7 x 13.8 x 13.8 inches. This model is designed for whole house applications, providing instant hot water for multiple fixtures.
Pros
- 100,000 BTU/hr heating capacity
- ±1°F precision temperature control
- Large LED display with touch panel
- Multiple security protections included
Cons
- Smaller 4.3 gallon capacity than competitors
- Indoor installation only
- Lower flow rate than top picks
Good fit if
- You need precise temperature stability
- You have indoor gas lines
- You want simple digital controls
Skip if
- You require outdoor installation
- You need high flow rates
- You prefer propane fuel
Verdict: VEVOR 4.3 Gal Gas Tankless Water Heater fits users who prioritize temperature precision and indoor placement over maximum flow capacity. It serves small to medium households needing reliable instant hot water.
Specifications side by side
| Spec | Bosch 9.4 GPM Natural Gas Tankless Water Heater | Rheem IKONIC 10.1 GPM Natural Gas Tankless Water Heater | Noritz 7.5 GPM Outdoor Natural Gas Water Heater | Bosch Natural Gas Tankless Water Heater | Reliance 199,000 BTU Gas Tankless Water Heater | Ranein 4.3 GPM Indoor Natural Gas Tankless Water Heater | VEVOR 4.3 Gal Natural Gas Tankless Water Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas, Propane | Natural Gas | Gas |
| Flow Rate | 9.4 GPM at 35F rise | 10.1 GPM | 7.5 GPM | 8.3 GPM at 35F rise | not stated | 4.3 GPM | not stated |
| BTU | 199,000 BTU/hr max input | 180,000 BTUs | 199,000 BTU | 175,000 BTU/hr max input | 199,000 BTU | 100,000 BTU | 100,000 BTU/hr |
| Installation Location | not stated | Indoor | Outdoor | not stated | Indoor/Outdoor | Indoor | Indoor |
| Capacity | not stated | not stated | not stated | not stated | not stated | not stated | 4.3 Gal |
| Temperature Control | not stated | not stated | not stated | not stated | not stated | 95°F-155°F | ±1°F |
| Dimensions | 31 x 18 x 12 in | 28.6 x 17.3 x 13.7 inches | not stated | 30.5 x 17.9 x 11.3 in | 11 x 11 x 18 inches | 25.6 x 16.9 x 16.9 inches | 21.7 x 13.8 x 13.8 inches |
| Use | not stated | not stated | not stated | not stated | not stated | Whole House | Whole House |
| Features | not stated | WiFi | not stated | not stated | not stated | not stated | not stated |
| Weight | 76 pounds | 86 pounds | not stated | 80 pounds | 8.5 pounds | not stated | 19.8 pounds |
| Color | Gray | Gray | Beige | Gray | White | Gray-NG | Silver Gray |
| Model | 940 ES NG | RECTGH-SR10iN | NR98-OD NG | 830 ES NG | X3-199 | RH10K | JSQ30-A |
| Size | not stated | 10.1 GPM (w Recirc) | 7.5 GPM | not stated | not stated | 4.3 GPM Indoor | 4.3 Gal |
For a related comparison, read apec water apec tankless ro water alternatives.
Frequently asked questions
Which tankless water heater has the highest flow rate in this list?
The Rheem IKONIC offers the highest flow rate at 10.1 GPM. This model is designed for large families with high hot water demands. It includes Wi-Fi connectivity for smart control. The unit weighs 86 pounds and measures 28.6 inches in height. This makes it the top choice for maximum output.
Is there a tankless water heater suitable for outdoor installation?
Yes, the Noritz NR98-OD NG is designed for outdoor use. It provides a 7.5 GPM flow rate with natural gas. This unit is vent-free, which simplifies installation for exterior locations. It measures 7.5 GPM in size and comes in a beige color. It is ideal if you prioritize efficiency and outdoor placement.
Which model is the most compact for tight spaces?
The Reliance X3-199 is the most compact option listed. It measures only 11 inches wide and 18 inches high. The unit weighs just 8.5 pounds, making it very lightweight. It delivers 199,000 BTU of heat in a small package. This makes it suitable for high-output needs in confined areas.
Does any alternative include smart home connectivity?
The Rheem IKONIC RECTGH-SR10iN includes Wi-Fi connectivity. This feature allows for smart control of the water heater. It is designed for indoor installation in natural gas homes. The unit provides 10.1 GPM of flow. This makes it a strong option for households needing remote monitoring and control.
What is the smallest flow rate available among these options?
The Ranein RH10K has the lowest flow rate at 4.3 GPM. It is designed for indoor multi-fixture households. The unit features copper durability for long-term reliability. It measures 16.9 inches wide and 25.6 inches high. This model fits buyers who need reliable on-demand heating for medium-sized homes.
Which heater is best for whole-house use with precise temperature control?
The VEVOR JSQ30-A is designed for whole-house use indoors. It prioritizes precise temperature control over maximum flow capacity. The unit holds 4.3 gallons and weighs 19.8 pounds. It measures 13.8 inches wide and 21.7 inches high. This model serves small to medium households needing reliable instant hot water.
How does the Bosch 830 ES NG compare to the 940 model?
The Bosch 830 ES NG provides 8.3 GPM, which is lower than the 940 ES NG's 9.4 GPM. The 830 model weighs 80 pounds and measures 30.5 inches high. It offers flexible venting and strong heating capacity. This makes it a reliable alternative for large households needing high-flow performance.