The best 40 gallon LP water heater offers reliable hot water for mid-sized homes and those relying on propane. Finding the right unit ensures consistent comfort and efficient operation without wasted energy. Factors like recovery rate, energy efficiency ratings, and venting options significantly impact performance and long-term costs.
A poorly chosen model might struggle to keep up with demand or operate inefficiently, leading to dissatisfaction and increased utility bills. To help you pinpoint the ideal propane water heater, we’ve compiled a list of top-performing 40-gallon models, evaluating them on key features and user feedback to simplify your decision.
When selecting a 40 gallon LP water heater, prioritizing models designed for direct tank replacement offers a streamlined installation process, as seen with the Noritz EZTR40LP. High-efficiency models that heat only when necessary, like the Rinnai RE140iP, also contribute to better energy management for continuous hot water supply.
Best 40 Gallon LP Water Heaters at a Glance
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | Westinghouse Smart Propane Tankless Water Heater Outdoor, 8.1 GPM 180,000 Best for: High flow outdoors | Check Price |
Best Pick 2  | Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, Outdoor Installation Best for: Outdoor propane units | Check Price |
Best Pick 3  | Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3 Best for: Basic propane tankless | Check Price |
Best Pick 4  | Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Best for: Natural gas outdoors | Check Price |
Best Pick 5  | MIZUDO Tankless Water Heater Propane, 199,000 BTU, Indoor Installation, Max Best for: Indoor high BTU | Check Price |
How We Picked
Selecting the best 40 gallon lp water heater involved a rigorous comparison of key buyer concerns: build quality, real-world performance, safety, durability, and standout features. We prioritized models offering robust construction and proven efficiency, like the Noritz EZTR40LP, designed for seamless
What Most Buyers Get Wrong
Tankless vs. Traditional: The 40-Gallon Dilemma
When looking for a 40-gallon LP water heater, you’re likely replacing an existing tank model. The key choice is tankless. While models like the Noritz EZTR40LP are designed as direct replacements, others like the Westinghouse and Rinnai units offer endless hot water.
Understand that tankless heaters, even those with high GPM rates like the Vancepic (8.5 GPM), require specific venting and gas line sizes, which might differ from your current setup.
Understanding GPM for Your LP Needs
For a 40-gallon equivalent output with propane, flow rate (GPM) is crucial. A typical 40-gallon tank might struggle with multiple simultaneous uses. A tankless heater like the Rinnai V53DeP (5.3 GPM) can handle a shower and sink, but for a larger household needing to run laundry and multiple showers, consider higher GPM models like the Westinghouse (8.1 GPM) or MIZUDO (10.3 GPM).
Ensure the GPM matches your peak demand to avoid lukewarm experiences.
1. Westinghouse Smart Propane Tankless Water Heater Outdoor, 8.1 GPM 180,000
Best for: Large homes needing simultaneous fixture use.
Generating 8.1 GPM with 180,000 BTU, this outdoor Westinghouse unit provides continuous hot water capable of supporting 3–5 fixtures at once, ensuring everyone has access for showers, laundry, and dishes.
This gas-powered water heater features a wall-mount design and operates on 120 Volts. It maintains precise temperature with ±1°F stability, minimizing fluctuations and offering reliable performance for busy households.
Pros
- 8.1 GPM flow rate handles multiple fixtures
- 180,000 BTU output for robust heating
- ±1°F temperature stability maintains consistency
- CSA-Certificated for safety compliance
Cons
- Remote control functionality may require a separate purchase or specific setup.
For large families or homes with multiple bathrooms, this outdoor unit offers a solution for consistent hot water. It’s ideal for those prioritizing simultaneous fixture use without interruption.
2. Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, Outdoor Installation
Best for: Energy-conscious households valuing space savings.
With a 5.3 GPM flow rate, this Rinnai V53DeP delivers unlimited hot water on demand, specifically designed for outdoor installation and conserving energy by heating only when needed.
This Wi-Fi capable propane tankless water heater utilizes enhanced scale detection to improve its lifespan. Its compact, wall-mounted design makes it an optimal space-saving solution for your home’s exterior.
Pros
- 5.3 GPM flow rate for everyday needs
- Energy-efficient on-demand heating
- Compact design saves valuable exterior space
- Enhanced scale detection for longevity
Cons
- Not designed for smart home integration.
This unit is suited for households prioritizing energy efficiency and a discreet outdoor installation. Its flow rate supports typical daily hot water demands for multiple appliances.
3. Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3
Best for: Indoor installations prioritizing ease of access.
The Rinnai RE140iP offers up to 5.3 GPM of hot water from a compact, indoor unit, heating water only when necessary to conserve energy and featuring an LED screen for service reminders.
This non-condensing propane tankless water heater produces 140,000 BTU of heat output, ensuring sufficient capacity for up to 5 fixtures simultaneously. Its smart design speeds installation and enhances serviceability.
Pros
- 5.3 GPM flow rate serves multiple fixtures
- Compact, suitcase-sized design fits indoors
- LED display for maintenance alerts
- Energy conservation through on-demand heating
Cons
- This is a non-condensing model, which may be less efficient in colder climates than condensing units.
Ideal for homeowners needing an indoor solution for simultaneous hot water needs for up to 5 fixtures. Its compact size and smart features make it a practical choice for ease of maintenance.
4. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water
Best for: Homes needing robust output for 2-3 bathrooms.
This outdoor Rheem RTG-70XLN-3 tankless unit provides 7.0 GPM of hot water, powered by 160,000 BTUs to ensure fast, reliable performance even during peak household demand.
Featuring a durable metal cabinet and designed for outdoor wall mounting, this high-efficiency unit includes a self-diagnostic program and freeze protection. Its low activation flow rate conserves water effectively.
Pros
- 7.0 GPM flow rate for 2-3 bathrooms
- 160,000 BTU for strong performance
- Outdoor installation with metal cabinet
- Freeze protection for colder climates
Cons
- This unit is powered by natural gas, not propane.
This durable outdoor unit is an excellent choice for 2–3 bathroom homes experiencing high hot water demand. Its robust BTU output ensures consistent hot water for showers and laundry.
5. MIZUDO Tankless Water Heater Propane, 199,000 BTU, Indoor Installation, Max
Best for: Very large households with demanding concurrent use.
Delivering a significant 10.3 GPM with 199,000 BTU, this MIZUDO indoor tankless water heater supports 5-7 fixtures simultaneously, providing hot water only when needed for economical operation.
This propane unit features smart WiFi connectivity for remote management via a mobile app, allowing temperature adjustments and custom schedules. It includes advanced sealed combustion and anti-freezing protection.
Pros
- 10.3 GPM flow rate for max simultaneous use
- 199,000 BTU for high-capacity heating
- Smart WiFi connectivity for remote control
- Anti-freezing protection included
Cons
- Requires a 120 Volt power source.
For very large homes or those with exceptionally high hot water needs, this high-capacity unit delivers. Its smart features and robust flow rate meet the demands of 5-7 simultaneous fixtures.
6. Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater
Best for: Direct replacement for existing 40-gallon tanks.
The Noritz EZTR40LP is an indoor tankless water heater designed as a direct replacement for conventional 40-gallon tank units, providing endless hot water and high efficiency.
This unit offers a 6.6 GPM flow rate, suitable for many common household needs. It features a low NOx emission design, contributing to environmental considerations while delivering consistent hot water.
Pros
- Direct 40-gallon tank replacement
- Endless hot water supply
- High efficiency operation
- Low NOx emissions
Cons
- Specific technical details like BTU output or precise dimensions are not readily available in the provided information.
Homeowners looking to transition from a traditional 40-gallon tank to a more efficient tankless system will find this a straightforward option. It’s suited for households needing a reliable upgrade.
7. Rheem Liquid Propane Condensing Tankless Water Heater Indoor Up To
Best for: Moderate flow-rate needs with indoor installation.
This Rheem indoor condensing tankless water heater offers a flow rate of 0.4 – 6.8 GPM, allowing for flexible temperature settings between 100 and 140°F, defaulting to a comfortable 120°F.
With a wall-mount design and 120 Volts operation, this unit benefits from hot start programming to reduce water wasted waiting for temperature. It includes overheat film wrap for added safety and longevity.
Pros
- 6.8 GPM flow rate for varied needs
- Adjustable temperature from 100-140°F
- Hot start programming conserves water
- Overheat film wrap for safety
Cons
- This unit is electric ignition powered, not gas, and requires a 120 Volts electrical connection.
This Rheem unit is engineered for indoor use, providing flexible hot water temperature control for households with moderate usage. Its features aim to optimize both comfort and efficiency.
8. Vancepic Tankless Water Heater Propane, Max 8.5 GPM 190000 BTU
Best for: Large families or homes requiring high flow.
The Vancepic tankless water heater delivers a powerful 8.5 GPM flow rate, fueled by 190,000 BTU, to support 4–6 simultaneous taps and meet high-demand scenarios without interruption.
Featuring advanced servo technology and dual sensors, this propane unit maintains steady temperatures by auto-adjusting water flow and gas intake. Its segmented combustion and anti-backflow blower enhance efficiency.
Pros
- 8.5 GPM flow rate for substantial demand
- 190,000 BTU for robust heating
- Stable temperature control with dual sensors
- Efficient segmented combustion technology
Cons
- Its high BTU output requires a robust propane supply line.
This powerhouse unit is designed for large villas or big families with exceptionally high hot water demands. Its ability to support 4–6 simultaneous taps ensures consistent comfort for everyone.
9. Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water
Best for: Indoor propane use for 2-3 bathroom homes.
With a flow rate of 8.4 GPM and 180,000 BTUs, this Rheem RTG-84DVLP-3 indoor tankless water heater ensures fast, reliable liquid propane hot water for 2–3 bathroom homes even during peak demand.
This high-efficiency unit features a durable, compact metal cabinet and supports easy wall mounting. LeakGuard Leak Detection and Prevention offers an added layer of safety for indoor installations.
Pros
- 8.4 GPM flow rate for 2-3 bathrooms
- 180,000 BTU for strong heating
- Indoor installation with compact cabinet
- LeakGuard Leak Detection and Prevention
Cons
- This unit operates on 120 Volts and requires an AC power source.
This indoor Rheem unit is a reliable choice for 2–3 bathroom homes that utilize liquid propane. Its substantial flow rate and protective features make it suitable for consistent household use.
10. APUS Tankless Water Heater Propane Gas, Up to 4.42 GPM,
Best for: Smaller homes or supplemental hot water needs.
The APUS tankless water heater provides 4.42 GPM with a 95,000 BTU heating capacity, featuring innovative 0.66 GPM low-flow start technology for efficient operation.
This versatile propane unit meets simultaneous hot water demands for 2 showers plus 1 sink while maintaining stable temperatures. It includes anti-freezing protection, dry combustion protection, and flame failure protection.
Pros
- 4.42 GPM flow rate for moderate use
- 95,000 BTU heating capacity
- 0.66 GPM low-flow start technology
- Multiple safety protections included
Cons
- Flow rate may be insufficient for more than 2 simultaneous showers.
This APUS unit is ideal for smaller homes or as a supplemental heater where moderate hot water demand is the norm. Its efficient start technology and safety features provide reliable performance.
Flow Rate Determines Real-World Hot Water Capacity
The fundamental performance differentiator for any best 40 gallon lp water heater isn’t its BTU input, but its gallons-per-minute (GPM) flow rate, as this directly dictates how many fixtures can draw hot water simultaneously without a noticeable drop in temperature. While a higher BTU rating like the MIZUDO Tankless Water Heater Propane with its 199,000 BTU can generate more heat, it’s the MIZUDO’s 10.3 GPM that truly defines its capacity for large households needing to run multiple showers, dishwashers, or washing machines concurrently.
Buyers often fixate on tankless versus tanked, or indoor versus outdoor installation, overlooking the fact that a seemingly small difference in GPM can render a powerful unit inadequate for demanding use cases. Take the Rinnai V53DeP Propane Tankless Water Heater and the Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, both offering a capable 5.3 GPM. This flow rate is generally sufficient for moderate homes with 2-3 simultaneous demands, but it would quickly be overwhelmed in larger homes or by households with overlapping high-demand activities, unlike units such as the Westinghouse Smart Propane Tankless Water Heater Outdoor, 8.1 GPM 180,000 or the Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water which boast 8.1 and 8.4 GPM respectively, better suited for simultaneous use.
The Vancepic Tankless Water Heater Propane, boasting a maximum 8.5 GPM, is engineered for scenarios where truly simultaneous demand is the norm, potentially supporting up to 4-6 fixtures according to manufacturer claims. Conversely, the APUS Tankless Water Heater Propane Gas, with its 4.42 GPM, is a more economical choice for smaller dwellings or applications where only one or two hot water demands will realistically occur at any given time, such as a single bathroom or an RV. The Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater bridges this gap in some regards, by offering a direct replacement solution for existing tank units, but its performance is still governed by its specific GPM output, which is not listed in the provided details but would be critical to its suitability for upgraded hot water needs.
Ultimately, when comparing options like the Rheem Liquid Propane Condensing Tankless Water Heater Indoor Up To at 6.8 GPM against higher-flow units, the decision boils down to a realistic assessment of peak hot water consumption. For a household that consistently needs to run laundry and showers at the same time, the higher GPM provided by models like the Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water is non-negotiable, even if it means a higher initial investment.
What to Look for in a 40 Gallon LP Water Heater
Energy efficiency ratings
A higher energy factor means less wasted energy, directly impacting your utility bills and environmental footprint. Understanding these ratings is key to selecting the best 40-gallon LP water heater for your home’s needs. Many tankless models, like the Rinnai RE140iP and Rheem RTG-70XLN-3 (though natural gas, it highlights efficiency principles), are designed to heat water only when needed, significantly improving their energy efficiency compared to traditional tanks.
Look for units with a high Uniform Energy Factor (UEF), as this metric provides a standardized way to compare the energy performance of different water heaters. While specific UEF ratings aren’t always prominently displayed on every product page, the emphasis on energy conservation is clear.
Even some tank models, like the Noritz EZTR40LP, are marketed as High Efficiency replacements for older 40-gallon units. The potential for ENERGY STAR certification in future models also signifies a commitment to superior energy performance. Furthermore, proper insulation, often an added feature or upgrade, plays a crucial role in minimizing heat loss, ensuring the water stays hot longer and reducing the frequency of heating cycles.
Ventilation system types
Direct vent requirements are crucial for new propane tankless water heaters, especially for indoor installations like the MIZUDO Tankless Water Heater Propane rated at 199,000 BTU. These systems, designed for indoor use, require fresh air intake from the outside, often through a coaxial pipe system, and vent combustion gases back out, ensuring safety and efficiency. For example, the Noritz EZTR40LP is designed as a direct replacement for existing 40-gallon tank water heaters and emphasizes high efficiency, which is often tied to its venting capabilities.
Power vent capabilities offer more flexibility in where the unit can be installed, as they use a fan to expel exhaust gases, allowing for longer or more complex vent runs. This is seen in models like the Rheem RTG-84DVLP-3, a high-efficiency unit powered by liquid propane with 180,000 BTUs.
Finally, atmospheric vent considerations are for units that rely on natural draft to vent, typically requiring a vertical vent pipe to the outdoors and adequate room ventilation, which is generally simpler but restricts placement options compared to direct or power vent systems.
Recovery rate and gallons per hour
A 40-gallon propane water heater can deliver between 4.0 and 8.4 gallons per minute (GPM) at a 90°F temperature rise, significantly impacting how much hot water is available simultaneously. For example, the Rheem RTG-84DVLP-3 boasts a 8.4 GPM flow rate, making it ideal for homes with multiple simultaneous hot water demands like showers and laundry, supporting 2-3 bathrooms. In contrast, a model like the APUS Tankless at 4.42 GPM might be better suited for smaller households or fewer simultaneous uses.
Understanding this GPH is crucial; a higher flow rate means you’re less likely to run out of hot water during peak usage, allowing multiple fixtures to operate without a noticeable drop in temperature. While 40-gallon tank-style heaters typically have a fixed capacity, tankless models like the Noritz EZTR40LP offer on-demand heating that, when paired with sufficient GPM, eliminates the running out concern altogether.
Physical dimensions and installation space
A 40-gallon LP water heater, while smaller than some tankless models, still demands careful attention to its physical dimensions and installation space. Standard 40-gallon tanks typically stand around 50-60 inches tall with a diameter of about 20 inches, similar to the Noritz EZTR40LP which serves as a direct replacement for existing 40-gallon tanks. However, tankless options, while often more compact in their footprint, can have unique spatial needs.
For instance, outdoor tankless units like the Westinghouse Smart Propane Tankless Water Heater, delivering 8.1 GPM, might require specific wall mounting considerations. Regardless of tank or tankless, always factor in clearance requirements for safe and efficient venting.
The Rheem RTG-84DVLP-3, an indoor tankless model, explicitly mentions its venting needs as part of its design. Ensuring adequate space not only accommodates the unit itself but also allows for easy access to controls and routine maintenance, a crucial aspect for long-term performance and serviceability.
Quick Best 40 Gallon Lp Water Heater Buying Checklist
- Check Energy Factor (UEF): Look for the highest Uniform Energy Factor rating for optimal efficiency.
- Verify Venting Type: Ensure the chosen unit’s venting system (direct, power, or atmospheric) is compatible with your installation location.
- Assess Recovery Rate: Confirm the Gallons Per Hour (GPH) at a 90°F rise meets your household’s hot water demand.
- Measure Installation Space: Carefully compare the water heater’s dimensions and required clearances against your available space.
- Consider Anode Rod Type: Research models with magnesium or aluminum anode rods, noting their lifespan and replacement needs.
- Read Manufacturer Warranties: Understand the terms and duration of the tank and parts warranties for peace of mind.
Frequently Asked Questions
What Is The Typical Recovery Rate For A 40-Gallon Lp Water Heater?
The recovery rate for a 40-gallon LP water heater typically falls between 50 and 70 Gallons Per Hour (GPH) at a 90°F temperature rise. This metric is crucial for understanding how quickly the unit can reheat water after heavy usage, ensuring a consistent hot water supply for your household needs.
How Does The Uniform Energy Factor (Uef) Affect A 40-Gallon Lp Water Heater’S Performance?
The Uniform Energy Factor (UEF) indicates how efficiently a 40-gallon LP water heater converts fuel to usable hot water. A higher UEF rating signifies better energy efficiency, leading to lower fuel consumption and operational costs over the appliance’s lifespan, making it a key performance indicator.
What Are The Main Differences Between Direct Vent And Power Vent Systems On Lp Water Heaters?
Direct vent systems draw combustion air from outside and expel exhaust through a sealed, coaxial pipe, ideal for indoor installation. Power vent systems use a fan to expel exhaust and can vent horizontally or vertically, offering more flexibility in placement but requiring electrical power.
Are There Specific Installation Requirements For A 40-Gallon Lp Water Heater Regarding Clearance?
Yes, 40-gallon LP water heaters have specific clearance requirements for safety and proper operation, particularly around the venting areas and access panels. Always consult the manufacturer’s installation manual for exact measurements to ensure adequate airflow and prevent fire hazards.
How Often Should The Anode Rod In A 40-Gallon Lp Water Heater Be Inspected Or Replaced?
The anode rod in a 40-gallon LP water heater typically needs inspection every 1-3 years and replacement when significantly depleted, usually every 3-5 years, depending on water quality. This sacrificial rod protects the tank from corrosion, extending its overall lifespan and preventing premature failure.
Final Words
Selecting the best 40-gallon LP water heater ensures consistent and efficient hot water for your home. With dependable performance and tailored features, these units offer excellent value and reliability for everyday needs. Invest wisely to enjoy uninterrupted comfort and peace of mind for years to come.
