The best 40 gallon propane water heater delivers consistent hot water reliably for homes needing ample supply, ideal for families or properties with high demand. When selecting a new unit, consider factors such as energy efficiency ratings, recovery rates, and warranty terms, as an ill-suited choice can lead to wasted energy and inconveniently lukewarm water. Different models offer varying tank insulation, burner designs, and venting configurations, influencing their operational cost and safety.
Prioritizing a unit with smart features or specific performance metrics can significantly enhance long-term satisfaction and avoid the pitfalls of inadequate heating. Explore our curated selection of top-performing 40-gallon propane water heaters, each chosen for its quality and value.
When considering a best 40 gallon propane water heater, a key feature is the tankless design for continuous hot water, as seen in models like the Rheem RTG-70XLP-3 which delivers up to 7.0 GPM. High-efficiency, non-condensing models are suitable for 2-3 bathroom homes with multiple hot water demands, powered by liquid propane with significant BTU output.
Best 40 Gallon Propane Water Heaters, At a Glance
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | NEW Rinnai RX180iN Condensing Smart Sense Natural Gas or Propane Best for: Smart homeowners | Check Price |
Best Pick 2  | Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Best for: Outdoor installations | Check Price |
Best Pick 3  | Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water Best for: Indoor installations | Check Price |
Best Pick 4  | Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000 Best for: High-flow needs | Check Price |
Best Pick 5  | APUS Tankless Water Heater Propane, 140,000 BTU Indoor Installation Up Best for: Compact spaces | Check Price |
How We Picked
We meticulously evaluated propane water heaters for the best 40 gallon propane water heater by focusing on core buyer needs. Build quality and durability were paramount, leading us to prioritize robust materials and established brand reputations like Rheem and Rinnai. Real-world performance was assessed by GPM capacity and BTU output, ensuring sufficient hot water for multiple fixtures, as seen in the Westinghouse and MIZUDO models.
Safety features and advanced technology, such as smart sensing and efficient heat exchangers, distinguished top contenders. Units with less detailed specifications or lower BTU ratings were ruled out to guarantee reliable performance and long-term value for discerning homeowners.
What Most Buyers Get Wrong
Flow Rate: More Than Just GPM
When choosing a propane water heater, especially one aiming for the capacity of a 40-gallon tank, GPM (gallons per minute) is crucial. Don’t just look at the maximum flow rate. Consider the simultaneous use capability, like the Ranein’s 3-4 water points or the MIZUDO’s 5-7.
If you have multiple showers running or a dishwasher going, a higher GPM is essential. Rheem models like the RTG-70XLP-3 and RTG-70DVLP-3 offer 7.0 GPM, suitable for multiple simultaneous uses, so assess your household’s peak demand.
Tankless vs. Tank: Understanding the BTU Difference
For those transitioning from a traditional 40-gallon tank heater, the transition to a tankless propane model involves understanding BTU (British Thermal Units) ratings. Higher BTU generally means faster heating and higher flow rates. Units like the MIZUDO (199,000 BTU) and Westinghouse (180,000 BTU) offer significant power, capable of supporting larger homes with multiple fixtures.
Compare this to the APUS (140,000 BTU) or the Outdoor Tankless (130,000 BTU). A higher BTU is often necessary to achieve the endless hot water promised by tankless technology, especially when mimicking the output of a larger tank.
1. NEW Rinnai RX180iN Condensing Smart Sense Natural Gas or Propane
Best for: Versatile Indoor/Outdoor Gas/Propane Home Use.
This Rinnai RX180iN features a dual-fuel system for natural gas or propane with a Smart Sense gas control, allowing installation indoors or outdoors. Its compact, suitcase-sized design delivers up to 10 GPM, supporting six fixtures simultaneously for continuous hot water.
With a 180,000 BTU heat output and an efficiency rating of 0.98 UEF, this Rinnai unit provides an impressive 10 gallons per minute flow rate, suitable for multiple demands. It operates at temperatures up to 140 degrees Fahrenheit and can withstand a maximum pressure of 150 PSI.
Pros
- Dual-fuel capability for natural gas or propane
- Up to 10 GPM flow rate for multiple fixtures
- Compact and lightweight design
- High efficiency at 0.98 UEF
Cons
- Outdoor installation requires a separate RX-OVC vent cap
This Rinnai unit is an excellent choice for homes needing flexible installation options and ample hot water. Its smart features and high performance make it ideal for busy households.
2. Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water
Best for: High-Efficiency Outdoor Propane for 2-3 Bathrooms.
The Rheem RTG-70XLP-3 provides high-efficiency heating with 160,000 BTUs, delivering up to 7.0 GPM for simultaneous use in 2-3 bathroom homes. Designed for outdoor installation, its durable metal cabinet ensures longevity.
This liquid propane model boasts a 7.0 GPM flow rate, reliably supplying hot water for showers and laundry. Its hot-start programming reduces cold water bursts, and it’s equipped with 1/2 inch gas line compatibility and industry-leading side-to-side clearances for easier installation.
Pros
- Up to 7.0 GPM flow rate
- Outdoor installation ready
- Hot-start programming for consistent temperature
- Durable metal cabinet
Cons
- Not suitable for indoor installation due to combustion venting
Ideal for homeowners with multiple bathrooms seeking consistent hot water outdoors. This Rheem unit balances high performance with a straightforward outdoor setup.
3. Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water
Best for: Indoor Propane for 2-3 Bathrooms.
The Rheem RTG-70DVLP-3 offers high-efficiency heating for indoor propane use, delivering up to 7.0 GPM for 2-3 bathroom homes. Its compact metal cabinet is designed for easy wall mounting.
With a powerful 160,000 BTU output and a 7.0 GPM flow rate, this unit meets demands for showers and laundry simultaneously. It features hot-start programming and an efficiency rating of 0.82, providing consistent hot water for everyday needs.
Pros
- 7.0 GPM flow rate suitable for multiple fixtures
- Designed for indoor installation
- Compact and durable metal cabinet
- Hot-start programming minimizes cold water bursts
Cons
- Lower efficiency (0.82 UEF) compared to some condensing models
This Rheem water heater is a solid choice for households needing reliable indoor propane hot water. It efficiently serves 2-3 bathrooms with its substantial flow rate.
4. Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000
Best for: Smart Outdoor Propane with Precise Temperature Control.
This Westinghouse Smart Outdoor Propane Tankless Water Heater delivers 8.1 GPM and 180,000 BTU, supporting 3-5 fixtures simultaneously. Its advanced self-modulating technology maintains a precise ±1°F temperature stability.
Designed for outdoor installation, the 8.1 GPM flow rate ensures endless hot water for showers, sinks, and appliances. With 180,000 BTU, it provides robust heating, and a remote control is included for convenient indoor operation.
Pros
- 8.1 GPM flow rate
- Precise ±1°F temperature control
- Outdoor installation optimized
- Supports 3-5 fixtures simultaneously
Cons
- Outdoor installation is mandatory, requiring weather protection.
Perfect for homeowners who want a smart, efficient outdoor propane solution with exceptionally stable water temperatures. It handles demands for multiple fixtures with ease.
5. APUS Tankless Water Heater Propane, 140,000 BTU Indoor Installation Up
Best for: Instant Indoor Propane with Zero Cold Water Tech.
The APUS Tankless Water Heater Propane features a 140,000 BTU burner and an oxygen-free copper heat exchanger for instant hot water in just 1 second. Its exclusive Zero Cold Water Technology eliminates wait times for consistent comfort.
This indoor unit provides hot water in 1 second with its 140,000 BTU output and offers a 6.8 Gallons Per Minute flow rate. It includes smart seasonal technology and a turbo flow mode, all controllable via WiFi through the Tuya APP for remote management.
Pros
- Provides hot water in 1 second
- Zero Cold Water Technology
- WiFi remote control with Tuya APP
- Durable oxygen-free copper heat exchanger
Cons
- 140,000 BTU may be less powerful for very high demand
This APUS unit is ideal for those prioritizing immediate hot water and smart home integration indoors. Its advanced technology ensures convenience and efficiency.
6. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water
Best for: Outdoor Natural Gas for 2-3 Bathrooms.
The Rheem RTG-70XLN-3, a high-efficiency natural gas water heater for outdoor installation, delivers up to 7.0 GPM, ideal for homes with 2-3 bathrooms. Its durable metal cabinet and self-diagnostic program enhance reliability.
Operating on natural gas with a 160,000 BTU output, this unit provides 7.0 GPM for simultaneous use of showers and laundry. Features include freeze protection, a low activation flow rate of 0.26 GPM, and an EZ-link cable for easy connection of multiple units.
Pros
- Up to 7.0 GPM flow rate
- Outdoor installation design
- Freeze protection for colder climates
- Self-diagnostic program for performance monitoring
Cons
- Uses natural gas, not propane
This Rheem model is a robust outdoor heating solution for homes using natural gas. It efficiently serves multiple hot water needs in 2-3 bathroom setups.
7. Ranein Propane Gas Tankless Water Heater, Indoor Max 4.3 GPM,
Best for: Compact Indoor Propane for 3-4 Water Points.
The Ranein Propane Gas Tankless Water Heater offers powerful on-demand heating with 100,000 BTU and 4.3 GPM, supporting 3-4 water points simultaneously. Its intelligent linkage system provides precise temperature control.
With a flow rate of 4.3 GPM and a maximum temperature of 155 degrees Fahrenheit, this indoor unit is efficient for kitchens and bathrooms. It features four intelligent preset modes, including 4-season auto-matching, and a kitchen default of 100°F.
Pros
- Supports 3-4 water points concurrently
- Four intelligent preset modes
- Precise temperature control
- Compact design for indoor spaces
Cons
- Lower flow rate (4.3 GPM) may not suit larger homes with simultaneous high demand.
This Ranein unit is well-suited for smaller homes or apartments seeking efficient and precise indoor propane hot water. Its multiple modes add significant convenience.
8. MIZUDO Tankless Water Heater Propane, 199,000 BTU, Indoor Installation, Max
Best for: High-Capacity Indoor Propane with WiFi Control.
The MIZUDO Tankless Water Heater Propane boasts a powerful 199,000 BTU and 10.3 GPM flow capacity, designed for large households with 5-7 fixtures. It offers smart WiFi connectivity for remote management and temperature adjustments via a mobile app.
This indoor unit delivers uninterrupted hot water for up to 7 fixtures simultaneously with its 10.3 GPM flow rate. It features advanced sealed combustion, automatic anti-freeze protection, and a maximum temperature of 149 degrees Fahrenheit.
Pros
- 10.3 GPM flow rate for large households
- Smart WiFi and app control
- Continuous hot water for 5-7 fixtures
- Automatic anti-freeze protection
Cons
- 199,000 BTU is a high heat output that requires adequate gas supply.
This MIZUDO is an excellent choice for large families or homes with significant hot water demands. Its smart features and high capacity ensure comfort and convenience.
9. Outdoor Tankless Water Heater, 130,000 BTU/5.3 GPM Propane Instant Hot
Best for: All-Weather Outdoor Propane for Home Use.
This Outdoor Tankless Water Heater provides 5.3 GPM and 130,000 BTU of propane power, suitable for 3-5 taps, ensuring daily household needs are met. Its wind-resistant construction and electronic freeze protection offer all-weather performance.
With a flow rate of 5.3 GPM and 130,000 BTU, this unit reliably supplies hot water for showers, kitchens, and basements. It features anti-freezing protection and dry combustion protection for durability in various environments, with a maximum temperature of 149°F.
Pros
- 5.3 GPM flow rate for multiple uses
- All-weather outdoor performance
- Electronic freeze protection
- Includes remote control for indoor operation
Cons
- 130,000 BTU may be insufficient for extreme simultaneous demand in very large homes.
This water heater is ideal for outdoor installations requiring reliable hot water regardless of weather. Its capacity serves typical household demands efficiently.
10. APUS Tankless Water Heater Propane Gas, Up to 4.42 GPM,
Best for: Compact Indoor Propane for 2 Showers + Sink.
The APUS Tankless Water Heater Propane delivers 95,000 BTU heating capacity with a 4.42 GPM flow rate, suitable for 2 showers plus 1 sink. Its innovative 0.66 GPM low-flow start technology conserves water and energy.
Featuring high-precision sensors and smart CPU technology, this indoor unit maintains stable temperatures even during peak usage. With 4.42 GPM and a heating capacity of 95,000 BTU, it ensures efficient hot water for simultaneous needs.
Pros
- 4.42 GPM flow rate for multiple fixtures
- 0.66 GPM low-flow start technology
- Precise temperature stability
- Overheat protection for safety
Cons
- 95,000 BTU is lower than many other tankless units, suited for moderate demands.
This APUS unit is a great fit for smaller to medium households needing efficient indoor propane hot water. Its low-flow start technology makes it an economical choice.
BTU Sizing Trips Up Best 40 Gallon Propane Water Heater Buyers
When selecting a best 40 gallon propane water heater, the singular factor that dictates long-term satisfaction is matching the unit’s BTU output to your household’s peak demand, not merely its flow rate.
While descriptions like Rinnai RX180iN Condensing Smart Sense Natural Gas or Propane’s One Model, Anywhere or Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water’s 7.0 GPM sound appealing, these figures are only half the story. The true performance bottleneck, especially during simultaneous high-draw events like a shower running while the dishwasher cycles, is the burner’s capacity to instantly vaporize water. This is where BTU, or British Thermal Units, becomes paramount.
A unit with a lower BTU rating, such as the Ranein Propane Gas Tankless Water Heater, Indoor Max 4.3 GPM, rated at 100,000 BTU, will struggle to maintain temperature under significant load, even if its GPM rating seems adequate on paper. Contrast this with the MIZUDO Tankless Water Heater Propane, 199,000 BTU, which boasts a significantly higher capacity, evident in its 10.3 GPM potential, and is designed for households with genuinely demanding simultaneous hot water needs.
Buyers often fixate on GPM, assuming more gallons per minute directly translates to endless hot water. However, a high GPM without sufficient BTU is like a wide pipe with a weak trickle – it can carry volume, but not at the necessary speed or temperature. The Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000 BTU, and the APUS Tankless Water Heater Propane, 140,000 BTU Indoor Installation Up to 5.5 GPM, illustrate this balance.
The Westinghouse, with its higher BTU, is better positioned to deliver consistent high-temperature water even when multiple fixtures are active; the APUS, with a lower BTU but still respectable GPM and a 0.66 GPM low-flow start technology, might be the right choice for smaller homes or those prioritizing efficiency over extreme simultaneous demand, provided the 140,000 BTU is sufficient.
The mistake is assuming that all tankless units in the same GPM range offer equivalent performance. The underlying engine – the BTU rating – determines how quickly and effectively that hot water can be produced. For instance, the Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water heater at 160,000 BTU provides a more robust heating capability than the Outdoor Tankless Water Heater, 130,000 BTU/5.3 GPM Propane Instant Hot, when both are running at capacity and supporting multiple outlets; the former unit will recover faster and maintain a more stable output.
Don’t let the GPM number blind you to the BTU reality.
For a household that experiences peak demand with three or more simultaneous hot water draws, the MIZUDO Tankless Water Heater Propane, 199,000 BTU, is the prudent selection.
What to Look for in a 40 Gallon Propane Water Heater
Energy efficiency ratings
For optimal performance and savings, prioritize a 40-gallon propane water heater with an ENERGY STAR certification, signifying superior energy efficiency. Look for a First Hour Rating (FHR) that matches your household’s peak demand; a higher FHR means more hot water is available initially. Aim for a standby heat loss percentage below 10% for maximum efficiency, ensuring less energy is wasted keeping stored water hot.
The best choice for energy-conscious homes is a model demonstrating both high FHR and low standby heat loss.
Ventilation systems
When selecting a 40-gallon propane water heater, ventilation is paramount for safety and efficiency. Direct vent models are ideal for homes without existing chimneys, as they draw combustion air from outside and vent exhaust gases through a side wall. Power vent units require a dedicated vent pipe, often a chimney, and are suitable for installations where direct venting isn’t feasible.
Ensure the chosen unit’s air intake requirements match your installation space to guarantee proper combustion and prevent backdrafting. Opt for direct vent for ease of installation in new spaces.
Anode rod material and type
The anode rod in your 40-gallon propane water heater is critical for preventing tank corrosion and ensuring longevity. Magnesium rods offer excellent protection, while aluminum rods are a lighter alternative. Hybrid rods, combining both metals, provide robust, all-around protection.
For extended tank life, choose a model with an extendable anode rod; this allows for easier replacement and continued protection throughout the heater’s lifespan. The best choice for maximum tank longevity is a hybrid, extendable anode rod.
Which Should You Choose?
- If you need to install the heater in a space that can be either indoors or outdoors, look for models with advanced venting systems and universal gas compatibility.
- If you have a large household with multiple simultaneous hot water demands, opt for a unit with a higher GPM (gallons per minute) rating and BTU output.
- If your primary concern is maximizing space and you only need hot water on demand, a tankless model designed for indoor installation is likely your best bet.
- If you prioritize convenience and don’t have access to natural gas, ensure the unit is specifically designed for propane and suited for outdoor installation.
Quick Best 40 Gallon Propane Water Heater Buying Checklist
- Check Energy Efficiency: Look for ENERGY STAR® certified models for potential savings.
- Verify Venting Type: Ensure the direct vent or power vent system suits your installation space.
- Assess First Hour Rating: Choose an FHR that meets your household’s peak hot water demand.
- Consider Tank Insulation: Better insulation reduces standby heat loss and improves efficiency.
- Inspect Anode Rod: Opt for a model with a durable anode rod to prevent corrosion.
- Confirm Gas Line Size: Ensure your existing propane line is compatible with the heater’s input.
Frequently Asked Questions
What Is The Typical Temperature Range For A 40 Gallon Propane Water Heater?
Most 40 gallon propane water heaters offer adjustable thermostat settings that typically range from 100°F to 140°F. This allows users to customize the hot water output for safety and comfort, ensuring just the right temperature for various household needs.
How Long Does A 40 Gallon Propane Water Heater Usually Last?
A well-maintained 40 gallon propane water heater typically lasts between 10 to 15 years. Regular servicing, including flushing the tank and checking the anode rod, significantly contributes to its overall lifespan and optimal performance.
What Is The First Hour Rating (Fhr) On A 40 Gallon Propane Water Heater?
The First Hour Rating (FHR) indicates how many gallons of hot water a 40 gallon propane water heater can deliver in the first hour of use. It’s a crucial metric for determining if the unit can meet your household’s peak demand for showers and appliances.
Are Propane Water Heaters More Energy-Efficient Than Electric Models?
Propane water heaters are generally considered more energy-efficient than electric models, especially in areas where electricity costs are high. They heat water more quickly and often have lower operating costs due to propane’s energy density.
What Is The Importance Of The Anode Rod In A 40 Gallon Propane Water Heater?
The anode rod in a 40 gallon propane water heater acts as a sacrificial component that corrodes instead of the tank lining. This protective mechanism prevents rust and extends the life of the water heater by mitigating internal damage.
Final Words
Investing in the best 40 gallon propane water heater ensures a reliable and efficient supply of hot water for your home. These units offer a robust solution for managing peak demand, providing comfort and convenience. Upgrade today for dependable performance and enjoy uninterrupted hot water for all your needs.