The best 40 gallon tall gas water heater provides reliable and efficient hot water for households needing ample supply. Choosing the right model ensures consistent comfort and avoids costly replacements. Variability in efficiency ratings, venting types, and advanced features means a mismatch can lead to wasted energy and subpar performance.
Factors like ignition systems and warranty support also distinguish superior options from those that falter prematurely. Consider these top picks to secure a durable and effective water heating solution for your needs.
For a best 40 gallon tall gas water heater, consider models offering robust flow rates and energy efficiency, such as the Rheem RTGH Series RRTGH84DVLN3701171, which provides 8.4 GPM with adjustable temperature settings from 100 to 140°F. Key considerations include an electric ignition and warranty coverage for peace of mind.
Best 40 Gallon Tall Gas Water Heaters at a Glance
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120 Best for: Powerful high-demand | Check Price |
Best Pick 2  | Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water Best for: Efficient indoor heating | Check Price |
Best Pick 3  | Westinghouse Smart Tankless Water Heater Gas Indoor, 7.9 GPM 180,000 Best for: Smart home ready | Check Price |
Best Pick 4  | Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Best for: Outdoor installation | Check Price |
Best Pick 5  | Rheem RTG-84XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Best for: Propane outdoor use | Check Price |
How We Picked
We prioritized build quality, real-world performance, safety, and durability when selecting the best 40 gallon tall gas water heater. Products were evaluated based on their stated flow rates and BTU output, crucial for meeting household hot water demands. We favored models with comprehensive warranty coverage and features like electric ignition or smart controls, indicating advanced technology and reliability.
Units with lower GPM or BTU ratings, or those lacking detailed specifications for durability, were ruled out. Similarly, models not clearly indicating suitability for residential use were excluded, ensuring only top-tier options were considered for lasting performance and homeowner satisfaction.
What Most Buyers Get Wrong
Tankless vs. Tank: Understanding Your Hot Water Needs
Deciding between a tankless and a traditional tank water heater is crucial. While a 40-gallon tank model offers a set amount of hot water, tankless units like the Rheem RTGH Series or Westinghouse Smart Tankless provide continuous hot water as needed. Consider your household’s peak demand.
If you frequently run multiple hot water appliances simultaneously, a high-flow tankless heater (e.g., Rheem RTG-84XLP-3 with 8.4 GPM) might be better suited than a tank model, even a tall one.
BTU and Flow Rate: The Power Behind Your Hot Water
For gas water heaters, especially those aiming to replace a 40-gallon tank’s capacity, understanding BTU (British Thermal Units) and GPM (Gallons Per Minute) is key. Higher BTUs mean faster heating. For tankless models like the Rheem RTG-95DVLP-3 (199,900 BTUs) or the Rinnai CX199iN, a high BTU output ensures rapid heating for continuous supply.
Paired with a sufficient GPM (like the 8.4 GPM of the Rheem RTGH84DVLN3701171), your home will have ample hot water, mimicking or exceeding the output of a traditional tank.
1. Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120
Best for: Best for high-demand homes with maximum flow.
A flow rate of 8.4 GPM ensures multiple hot water uses simultaneously, capable of reaching a maximum temperature of 140°F. This unit leverages its 157,000 BTUs to deliver consistent hot water when you need it most.
This model offers an extensive temperature range from 100 to 140°F, with a default setting of 120°F for immediate use. Its electric ignition system and exclusive Hot Start Programming contribute to efficient operation, all within a 17-11/16 inch width.
Pros
- 8.4 GPM flow rate for high demand
- 157,000 BTU heat output
- Exclusive Hot Start Programming
- Electric ignition for quick startup
Cons
- Labor warranty is only 1 year.
For households prioritizing uninterrupted hot water during peak usage, this tankless water heater provides the capacity and performance needed. It is ideal for larger homes managing multiple simultaneous demands.
2. Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water
Best for: Excellent for 2-3 bathrooms with natural gas.
Delivering up to 7.0 GPM, this natural gas heater is engineered to manage multiple hot water tasks like showers and laundry without interruption. Its 160,000 BTUs ensure rapid heating, ideal for busy households.
This high-efficiency tankless unit features an integrated digital display for easy temperature monitoring and adjustment up to 140°F. It supports a 1/2 inch gas line and Universal Venting Compatibility, simplifying installation for qualified professionals.
Pros
- 7.0 GPM flow rate for 2-3 bathrooms
- 160,000 BTU natural gas power
- Integrated digital display
- Hot-start Programming for efficiency
Cons
- Not compatible with smart home systems.
This Rheem is a strong choice for families needing reliable hot water for multiple fixtures operated simultaneously. It’s designed for efficient indoor installation using natural gas.
3. Westinghouse Smart Tankless Water Heater Gas Indoor, 7.9 GPM 180,000
Best for: Smart control for whole-home instant hot water.
With a 7.9 GPM flow rate and 180,000 BTU output, this unit provides endless instant hot water for showers, laundry, and dishwashing. Its ±1°F temperature control ensures precise comfort levels throughout the home.
This smart tankless heater allows for convenient control via a smartphone app or its LED display panel, enabling adjustments to water temperature from anywhere. It supports up to 150 PSI of water pressure and is designed for wall mounting.
Pros
- 7.9 GPM flow rate for whole-house use
- 180,000 BTU for rapid heating
- WIFI & APP Control for remote adjustments
- Precise ±1℉ Temperature Control
Cons
- Limited information on specific warranty details beyond 2-5 years support.
Homeowners who value advanced control and consistent, on-demand hot water will benefit from this smart tankless water heater. It’s perfect for managing simultaneous hot water needs across multiple bathrooms and appliances.
4. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water
Best for: Ideal for outdoor installation with natural gas.
This outdoor tankless gas water heater delivers a robust 7.0 GPM flow rate, powered by 160,000 BTUs for reliable hot water. Its design focuses on efficient operation and durability for external placement.
Featuring a self-diagnostic program and hot-start programming, this unit is built for consistent performance and quick response. It includes freeze protection and a low activation flow rate, making it suitable for various climates, with wall mounting capability.
Pros
- 7.0 GPM flow rate for 2-3 bathrooms
- 160,000 BTU heat output
- Self-diagnostic program
- Freeze protection for colder climates
Cons
- Maximum temperature is limited to 140°F.
This Rheem model is specifically suited for homeowners seeking an efficient outdoor solution for their hot water needs using natural gas. It’s a practical choice for 2-3 bathroom homes needing dependable performance.
5. Rheem RTG-84XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water
Best for: Robust liquid propane option for outdoor homes.
Designed for outdoor installation, this liquid propane tankless heater boasts an 8.4 GPM flow rate, capable of supplying abundant hot water for busy households. Its 180,000 BTUs ensure swift heating performance.
The unit features hot-start programming to minimize cold water bursts and supports 1/2 inch gas line compatibility for streamlined setup. Its compact design allows for easy wall mounting by a qualified installer, maintaining a clean exterior aesthetic.
Pros
- 8.4 GPM flow rate for high demand
- 180,000 BTU liquid propane power
- Hot-start Programming for comfort
- Compact design for easy mounting
Cons
- Designed only for outdoor installation.
This Rheem tankless water heater is an excellent option for homes that utilize liquid propane and require reliable hot water outdoors. It effectively supports multiple simultaneous uses for 2-3 bathroom configurations.
6. Rinnai CX199iN Condensing Smart Sense Commercial Natural Gas or Propane
Best for: Versatile commercial-grade unit for indoor or outdoor.
This condensing tankless water heater offers up to 11.1 GPM, supporting 7 fixtures simultaneously, powered by natural gas or propane. Its compact size, comparable to a small suitcase, makes it suitable for various installation spaces.
With a maximum temperature of 185°F and 199,000 BTUs, it ensures hot water availability even for demanding commercial or large residential use. The Smart Sense gas control system and Versa Vent technology allow for flexible indoor/outdoor installation.
Pros
- 11.1 GPM flow rate for high fixture count
- 199,000 BTU heating power
- Works with Natural Gas or Propane
- Indoor or Outdoor Versa Vent installation
Cons
- Requires specific RX-OVC vent cap for outdoor use.
This Rinnai unit is ideal for environments requiring high-volume hot water on demand, whether in commercial settings or large homes. Its dual fuel capability and versatile installation make it a flexible choice.
7. NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane
Best for: High efficiency condensing unit for dual fuel.
Providing up to 11 GPM with its high efficiency condensing technology, this unit offers continuous hot water for up to 7 fixtures. It operates on natural gas or propane, meeting diverse fuel needs.
The 199,000 BTU output ensures rapid water heating, supporting a maximum temperature of 140°F, ideal for various residential applications. Its Smart Sense gas control system and Versa Vent installation flexibility cater to both indoor and outdoor setups.
Pros
- 11 GPM flow rate for busy households
- 199,000 BTU heating capacity
- Uses Natural Gas or Propane
- High efficiency rating (UEF .98)
Cons
- Requires an RX-OVC vent cap for outdoor installation.
This Rinnai tankless water heater is suited for homes needing a high volume of hot water and the flexibility of dual-fuel capability. It’s a strong option for managing multiple simultaneous demands efficiently.
8. Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, Outdoor Installation
Best for: Compact propane heater for outdoor, moderate use.
This outdoor propane tankless water heater offers a 5.3 GPM flow rate, providing continuous hot water for essential needs. Its energy-efficient design heats water only when required, extending the unit’s lifespan.
The unit includes Wi-Fi capability for remote monitoring and enhanced scale detection features to maintain optimal performance. Its compact design is specifically suited for outdoor wall mounting, saving valuable indoor space.
Pros
- 5.3 GPM flow rate for moderate needs
- Propane powered for outdoor use
- Wi-Fi Capable for monitoring
- Enhanced Scale Detection for longevity
Cons
- Only suitable for outdoor installation.
This Rinnai model is a practical choice for homes needing reliable hot water outdoors, particularly those utilizing propane. It’s suited for smaller households or where simultaneous hot water demand is moderate.
9. Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3
Best for: Space-saving indoor propane heater with smart features.
This indoor propane tankless water heater delivers up to 5.3 GPM, providing endless hot water for up to 5 fixtures. Its smart design heats water only when necessary, optimizing energy conservation and unit lifespan.
Featuring an LED screen that provides service reminders and error codes, this unit enhances serviceability. The internal layout is cleaner for easier access, and it operates efficiently with 140,000 BTUs to heat water up to 140°F.
Pros
- 5.3 GPM flow rate for up to 5 fixtures
- Propane powered for indoor use
- LED screen with service reminders
- Energy conserving heating design
Cons
- The 140,000 Wattage listed for the technical spec appears to be an error and is likely representing BTUs.
Ideal for homeowners seeking an energy-efficient propane solution for indoor hot water, this Rinnai unit offers convenience and smart features. It’s well-suited for smaller homes or apartments with moderate hot water requirements.
10. Rheem RTG-95DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water
Best for: High capacity indoor liquid propane heater.
This indoor liquid propane tankless water heater provides an impressive 9.5 GPM flow rate, ideal for larger homes with multiple simultaneous hot water demands. Its 199,900 BTUs ensure rapid heating even during peak usage.
Featuring an integrated digital display and hot-start programming, comfort and efficiency are prioritized. The unit supports Universal Venting Compatibility and 1/2 inch gas line connections, facilitating easier installation by qualified professionals.
Pros
- 9.5 GPM flow rate for high demand
- 199,900 BTU liquid propane power
- Integrated Digital Display
- Hot-start Programming for comfort
Cons
- Not compatible with smart home systems.
This Rheem model is an excellent choice for households using liquid propane that require high-volume, on-demand hot water indoors. It is particularly effective for homes with 2-3 bathrooms managing simultaneous use.
Tankless BTU vs GPM: The Real Decider
When scrutinizing options for a best 40 gallon tall gas water heater, the primary decision hinges on balancing BTU input with GPM output, not on the perceived advanced features. High BTUs, like the 180,000 BTU on the Westinghouse Smart Tankless Water Heater Gas Indoor or the 199,900 BTUs of the Rheem RTG-95DVLP-3, are necessary to heat water rapidly enough to meet high demand, but they are useless if the unit cannot deliver sufficient gallons per minute (GPM) to that demand. The true determinant of a tankless unit’s capacity is its GPM rating, as this directly reflects how much hot water can be supplied simultaneously.
A unit with a robust BTU but a lower GPM, such as the Rinnai V53DeP Propane Tankless Water Heater with only 5.3 GPM, will struggle to keep up with multiple simultaneous demands like a shower and a dishwasher running at once, regardless of its powerful heating capability.
The Rheem RTGH Series 8.4 GPM 157,000 BTU and the Rheem RTG-84XLP-3 both offer a strong 8.4 GPM, indicating they are engineered to handle substantial hot water needs. However, the former specifies 157,000 BTU, while the latter lists 180,000 BTU. While both will deliver ample hot water for most 2-3 bathroom homes, the higher BTU unit theoretically has more capacity to recover faster or handle colder incoming water temperatures without sacrificing flow.
Conversely, the Rheem RTG-70DVLN-3 and Rheem RTG-70XLN-3, both rated at 7.0 GPM, are best suited for smaller loads, ideal for perhaps one bathroom or light concurrent use. Their 160,000 BTUs are perfectly aligned with this lower GPM, signifying a cohesive design for a more modest hot water requirement.
The common pitfall among buyers is fixating on the number of BTUs as if it were the sole indicator of performance. This overlooks the fundamental constraint: the GPM. A unit like the Rinnai CX199iN or NEW Rinnai RX199iN, both offering significant gas input and the versatility of indoor/outdoor installation, will still be limited by their GPM output.
If the chosen unit’s GPM does not meet the peak demand of your household appliances and fixtures running concurrently, you will experience lukewarm water and frustration, irrespective of the raw heating power. Therefore, always prioritize matching the GPM to your household’s simultaneous hot water usage, then ensure the BTU input is sufficient to support that GPM.
For households that consistently run multiple high-demand fixtures at once, the Rheem RTG-95DVLP-3, with its class-leading 9.5 GPM capability and 199,900 BTUs, represents the upper echelon of domestic tankless performance, designed for extreme demand where others might falter.
What to Look For in a 40 Gallon Tall Gas Water Heater
Energy efficiency uef rating
When selecting a 40-gallon tall gas water heater, prioritize a Uniform Energy Factor (UEF) rating. Higher UEF scores mean greater energy efficiency, translating to lower monthly bills. Look for models with a UEF of 0.67 or higher, as this is the current federal minimum for gas storage water heaters.
While higher UEF units often have a slightly higher upfront cost, the long-term savings on gas consumption makes them the superior choice for most homeowners. Opt for models with 0.70 UEF or above for significant and sustained cost reductions.
Ventilation type
Consider the ventilation system carefully. For optimal safety and efficiency, a direct-vent system is the best choice. These units draw combustion air from outside and vent exhaust gases directly outside through a sealed system, preventing drafts and potential indoor air quality issues.
Powervent systems offer flexibility in placement but require an electrical outlet and exhaust fan. Natural draft (atmospheric vent) models are the most basic and rely on a chimney, but their efficiency is generally lower and they require adequate airflow to function safely.
Choose direct-vent for a sealed, efficient, and safe operation.
First hour rating fhr
Your household’s peak hot water demand dictates the First Hour Rating (FHR) you need. The FHR tells you how many gallons of hot water the heater can supply in the first hour of high usage. For a typical family, a 40-gallon tank usually requires an FHR between 60-77 gallons.
If your family frequently runs multiple appliances and fixtures simultaneously, consider a model closer to the higher end of this range. A higher FHR ensures you won’t run out of hot water during busy periods.
Select an FHR of 70 gallons or more for reliable hot water delivery.
Anode rod material
The anode rod is crucial for protecting your water heater’s tank from corrosion. Magnesium rods offer the most aggressive corrosion protection but may deplete faster in areas with hard water. Aluminum rods are a good compromise, providing decent protection with a longer lifespan.
Zinc-hybrid rods combine aluminum and zinc for enhanced performance, especially in areas with both hard water and sulfur. For maximum tank longevity, especially if you have hard water, a zinc-hybrid anode rod is the best investment.
Choose a model with a zinc-hybrid anode rod to ensure the longest lifespan for your heater.
Which Should You Choose?
- If you need to supply abundant hot water for a large household with multiple simultaneous uses (like showers and laundry), look for a tankless model with a GPM rating of 8.4 or higher.
- If your priority is energy efficiency and you have a medium-sized household, opt for a tankless heater with a GPM of around 7.0 that can be powered by either natural gas or propane.
- If you need a flexible installation option that can work indoors or outdoors and use either gas type, consider a condensing tankless model with smart gas control.
- If you have a smaller demand for hot water or are looking for a more budget-friendly tankless option, a unit with a GPM of around 5.3 might be sufficient.
Quick Best 40 Gallon Tall Gas Water Heater Buying Checklist
- Verify UEF Rating: Higher UEF means better efficiency and lower bills.
- Check Venting Type: Ensure the chosen model’s venting system is compatible with your installation space.
- Assess First Hour Rating: Match the FHR to your household’s peak hot water demand to avoid running out.
- Inspect Anode Rod: Look for models with durable anode rods to ensure tank longevity.
- Consider Ignition Type: Decide between electronic ignition or pilot light based on convenience and energy savings.
- Review Warranty Terms: Examine the tank and parts warranty for peace of mind.
Frequently Asked Questions
What Is The Primary Advantage Of A 40-Gallon Tall Gas Water Heater?
The primary advantage of a 40-gallon tall gas water heater is its balance of capacity and energy efficiency for medium-sized households. It provides sufficient hot water for typical daily needs without the higher energy consumption of larger tanks, making it a cost-effective solution.
How Does The Uef Rating Affect The Performance Of A 40-Gallon Tall Gas Water Heater?
The Uniform Energy Factor (UEF) rating directly indicates the energy efficiency of a 40-gallon tall gas water heater, with higher numbers signifying better performance. A higher UEF means less energy is wasted, leading to lower utility bills and a reduced environmental impact over the heater’s lifespan.
What Is The Significance Of The First Hour Rating (Fhr) For This Type Of Water Heater?
The First Hour Rating (FHR) is crucial as it measures how much hot water a 40-gallon tall gas water heater can supply in the first hour of peak demand. This metric helps ensure the unit can meet simultaneous hot water needs, like showers and laundry, without interruption.
Why Is The Anode Rod Material Important For A 40-Gallon Tall Gas Water Heater?
The anode rod material is vital for protecting the 40-gallon tall gas water heater’s tank from corrosion. Different materials like magnesium or aluminum sacrifice themselves to prevent the steel tank from rusting, thus extending the unit’s operational life and preventing premature failure.
Can A Power-Vented 40-Gallon Tall Gas Water Heater Be Installed In Any Location?
A power-vented 40-gallon tall gas water heater can be installed in more locations than a natural draft model because it doesn’t rely on natural buoyancy for exhaust. It requires an electrical outlet for the fan but offers greater flexibility in venting, often allowing installation in closets or interior walls.
Final Words
Investing in the best 40 gallon tall gas water heater ensures a reliable supply of hot water for your household’s daily demands. These units offer a practical blend of capacity and efficiency, leading to comfort and potential savings. Upgrade your system today for consistent performance and peace of mind.
