Best 40 Gallon LP Water Heaters: Top 10 Picks

The best 40 gallon LP water heater provides reliable, on-demand hot water for homes not connected to natural gas lines, ideal for rural properties or workshops. Selecting the right unit involves considering factors like energy efficiency ratings, venting requirements, and physical dimensions to ensure optimal performance and longevity. A misstep can lead to inadequate hot water supply, increased fuel consumption, or premature system failure, ultimately costing you more in repairs and wasted energy.

This curated list breaks down the top 10 40-gallon propane water heaters available in 2026 to help you find the perfect fit without the guesswork.

The best 40 gallon LP water heater offers efficient on-demand hot water and is often a tankless model designed for propane. Products like the Noritz EZTR40LP provide endless hot water by directly replacing existing 40-gallon tank water heaters with a high-efficiency, low-NOx indoor tankless unit.

Our Best 40 Gallon LP Water Heater Picks

Image	Product	Buy
Best Pick 1	Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000 Best for: Outdoor smart living	Check Price
Best Pick 2	Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Best for: Outdoor propane efficiency	Check Price
Best Pick 3	Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Best for: Natural gas homes	Check Price
Best Pick 4	Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater Best for: Tank replacement	Check Price
Best Pick 5	Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water Best for: Indoor natural gas	Check Price

How We Picked

To identify the best 40 gallon LP water heater options, we focused on build quality, real-world performance, safety, durability, and standout features. We prioritized models offering robust BTU output and high GPM flow rates, like the Westinghouse and Rheem RTGH Series, ensuring consistent hot water availability. Units deemed less suitable for demanding use or lacking advanced safety protocols were ruled out.

Models featuring flexible installation, like the Mizudo, and those with enhanced efficiency were also given strong consideration, reflecting a commitment to long-term value and user satisfaction for 2026.

What Most Buyers Get Wrong

Tankless vs. Tank: What’s Right for Your 40 Gallon Needs?

When considering a 40-gallon LP water heater, the biggest decision is tankless versus traditional. Traditional tank models, like the GE Appliances 30 Gallon Electric Water Heater (though this is electric, it illustrates tank capacity), offer simplicity. However, models like the Noritz EZTR40LP promise endless hot water, a key benefit of tankless systems.

Understand that tankless units like the Rheem RTG-70XLP-3 or CAMPLUX Climatech 5 offer on-demand heating, potentially saving energy if you don’t consistently use a full 40 gallons, but require a larger BTU input.

Propane (LP) vs. Natural Gas: Fueling Your Choice

The LP in a 40-gallon LP water heater signifies Liquid Propane. This is crucial if you don’t have a natural gas line. Products like the Westinghouse Smart Outdoor Propane Tankless Water Heater and Rheem RTG-84DVLP-3 are specifically designed for propane.

Be aware that propane models often have different BTU ratings and may require different venting than natural gas counterparts, such as the Rheem RTG-70XLN-Always verify fuel compatibility for your specific installation location.

1. Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000

Best for: For homes needing plentiful hot water on demand.

This Westinghouse unit provides up to 8.1 GPM with 180,000 BTU heating, allowing simultaneous use of multiple hot water fixtures. Its self-modulating technology maintains precise ±1°F temperature stability for consistent comfort.

Designed for outdoor installation, this gas-powered water heater operates on 120 volts and can handle a maximum pressure of 150 PSI. It supports 3-5 fixtures, including showers, sinks, and appliances, ensuring you won’t run out of hot water.

Pros

• 8.1 GPM flow rate for simultaneous use
• ±1°F temperature stability
• 180,000 BTU heat output
• Suitable for 3-5 fixtures

Cons

• Requires outdoor installation, limiting placement options.

This is an excellent choice for larger families or homes with high simultaneous hot water demand. Install it outdoors to ensure continuous hot water for all your needs.

2. Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water

Best for: For 2-3 bathroom homes demanding efficient hot water.

The Rheem RTG-70XLP-3 is a high-efficiency tankless unit delivering 7.0 GPM from liquid propane, capable of supporting 2-3 bathroom homes. It provides fast, reliable hot water even during peak demand.

With 160,000 BTUs of heat output and operating at 132 watts with 120 volts, this outdoor-only model features hot-start programming for quicker hot water delivery. Its durable metal cabinet is designed for wall mounting by a qualified installer.

Pros

• 7.0 GPM flow rate
• 160,000 BTU heat output
• Hot-start programming
• Suitable for 2-3 bathrooms

Cons

• Outdoor installation only, potentially exposing it to elements.

Ideal for households of moderate size that frequently use multiple hot water sources. This unit offers efficient and continuous hot water for showers, laundry, and more.

3. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water

Best for: For those needing natural gas, high-efficiency tankless water.

This Rheem RTG-70XLN-3 natural gas tankless heater provides a high flow rate of 7.0 GPM, ideal for homes with 2-3 bathrooms. Its 160,000 BTU output ensures hot water is available even during peak usage.

Designed for outdoor installation, this unit features self-diagnostic programs, hot-start programming, and freeze protection, all powered by natural gas. It efficiently delivers hot water with a low activation flow rate and includes a digital display.

Pros

• 7.0 GPM flow rate
• 160,000 BTU heat output
• Self-diagnostic program
• Freeze protection

Cons

• Requires connection to a natural gas line and outdoor installation.

Perfect for replacing an older natural gas water heater in a 2-3 bathroom home, offering continuous hot water. The outdoor design is suitable for homes where indoor space is limited.

4. Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater

Best for: For convenient direct replacement of 40-gallon tanks.

The Noritz EZTR40LP offers endless hot water by directly replacing your existing 40-gallon tank water heater, providing a high-efficiency solution. This indoor unit is designed for straightforward installation.

With a flow rate of 6.6 Gallons Per Minute, this tankless model minimizes energy waste compared to traditional tanks. It is engineered with Low NOx emissions for environmental consideration and operates on 120 volts.

Pros

• Direct 40-gallon tank replacement
• Endless hot water supply
• High efficiency
• Low NOx emissions

Cons

• Flow rate of 6.6 GPM may be insufficient for very high simultaneous usage.

This is an excellent switch for homeowners looking to upgrade from a standard 40-gallon tank to an efficient, on-demand system. It’s ideal for ongoing hot water needs without tank capacity limits.

5. Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water

Best for: For indoor natural gas homes needing reliable hot water.

The Rheem RTG-70DVLN-3 delivers up to 7.0 GPM of hot water powered by natural gas, making it suitable for homes with 2-3 bathrooms. Its 160,000 BTU heat output ensures rapid replenishment.

This indoor tankless unit features a compact metal cabinet and high energy efficiency, operating on 120 volts. Integrated digital display and hot-start programming provide user convenience, with universal venting compatibility for easier installation.

Pros

• 7.0 GPM flow rate
• 160,000 BTU heat output
• Integrated digital display
• High energy efficiency

Cons

• Requires natural gas connection and indoor installation space.

Best for homes with an existing natural gas line that require consistent hot water without taking up excessive space. This indoor unit is perfect for apartments or houses where outdoor placement isn’t feasible.

6. CAMPLUX Climatech 5 Tankless Water Heater Propane Outdoor, 5.28 GPM

Best for: For outdoor liquid propane users needing 3-5 simultaneous points.

The CAMPLUX Climatech 5 tankless propane heater offers up to 6.4 GPM, providing 5.28 GPM instant hot water for 3-5 simultaneous water points. This unit is CSA certified for safety.

Running on liquid propane at 150,000 BTU per hour, this outdoor unit features anti-freezing and dry combustion protection, operating on 120 volts. It can deliver 105°F water at a 2 GPM flow rate based on a 65°F inlet temperature.

Pros

• 6.4 GPM maximum flow rate
• Supports 3-5 simultaneous points
• CSA Certified
• Anti-freezing protection

Cons

• Requires outdoor installation and liquid propane tanks.

This is an excellent option for outdoor applications, such as garages or remote cabins, needing on-demand hot water for multiple uses. It’s designed to handle showers and laundry simultaneously.

7. MIZUDO Tankless Water Heater Propane, Indoor or Outdoor Convertible Installation,

Best for: For flexible indoor/outdoor installation with smart control.

The MIZUDO Tankless Water Heater uses propane and offers flexible indoor or outdoor installation with convertible kits, allowing for 5.1 GPM flow. This unit includes smart WiFi and app control for remote management.

With a heat output of 120,000 BTU per hour and a maximum pressure of 150 PSI, this water heater is CSA Certified and features automatic anti-freeze protection. It supports 2 to 4 usage points and operates on 120 volts.

Pros

• 5.1 GPM flow rate
• Indoor/Outdoor convertible installation
• WiFi & App Control
• Automatic Anti-Freeze Protection

Cons

• Requires separate purchase of accessory kits for installation flexibility.

This propane water heater is ideal for homeowners seeking modern convenience and adaptability in installation. Control your hot water remotely to suit your lifestyle and home layout.

8. Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120

Best for: For high-demand homes seeking robust hot water flow.

The Rheem RTGH Series delivers an impressive 8.4 GPM with a 157,000 BTU heat output, ensuring ample hot water for demanding households. It offers available temperature settings from 100 to 140°F.

This model includes exclusive hot start programming for faster hot water delivery and an overheat film wrap for added safety. It operates on 120 volts and is wall-mountable, featuring an electric ignition system.

Pros

• 8.4 GPM maximum flow rate
• 157,000 BTU heat output
• Exclusive Hot Start Programming
• Adjustable temperature settings (100-140°F)

Cons

• Coverage includes 1 year labor, 15 year heat exchanger, and 5 year parts warranty, which may be shorter than some competitors.

This Rheem unit is perfect for larger homes or households with very high hot water consumption. It’s designed to provide rapid and consistent hot water for multiple simultaneous uses.

9. Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water

Best for: For indoor liquid propane installations with high flow needs.

The Rheem RTG-84DVLP-3 is a high-efficiency indoor tankless unit providing 8.4 GPM flow rate with 180,000 BTUs of power from liquid propane. It is designed for 2-3 bathroom homes with multiple hot water demands.

This unit features LeakGuard Leak Detection and Prevention for added safety and operates on 120 volts with a maximum temperature setting of 140°F. Its durable, compact metal cabinet supports easy wall mounting by a qualified installer.

Pros

• 8.4 GPM flow rate
• 180,000 BTU heat output
• LeakGuard Leak Detection
• Suitable for 2-3 bathrooms

Cons

• Requires a liquid propane supply and indoor installation.

This is an excellent choice for homeowners who need significant hot water capacity indoors and utilize liquid propane. It’s well-suited for busy households with simultaneous shower and appliance usage.

10. GE Appliances 30 Gallon Electric Water Heater with Adjustable Thermostat,

Best for: For small households prioritizing tank capacity and recovery.

The GE Appliances 30 Gallon Electric Water Heater boasts a REAL CAPACITY, delivering the most hot showers from a true 30 gallons of water. Its Quick Recovery feature maximizes performance, outputting 53 gallons in the first hour.

This floor-mounted electric unit operates on 240 volts with a 5500-watt heat output, suitable for households of 1-3 persons. It features an adjustable thermostat up to 150°F and a maximum pressure of 125 PSI for reliable operation.

Pros

• True 30-gallon capacity
• 53 gallons first-hour rating
• Quick Recovery
• Adjustable thermostat up to 150°F

Cons

• Limited to 30 gallons capacity without on-demand heating, requiring careful usage for larger needs.

This GE electric water heater is a solid option for smaller households or single-family homes where consistent hot water for 1-3 people is needed. It ensures a dependable supply for daily routines.

BTU Level Isolates Performance in Propane Water Heaters

When selecting a best 40 gallon lp water heater, the actual difference between models boils down almost entirely to their BTU output and the resulting GPM flow rate it supports, especially for outdoor tankless units. While brands like Rheem offer variations such as the RTG-70XLP-3 and the RTG-84DVLP-3, the critical distinction lies in their BTU ratings and consequently their GPM capabilities. The Rheem RTG-84DVLP-3, boasting 180,000 BTUs and an 8.4 GPM flow rate, is engineered to handle higher simultaneous demands—think multiple showers running at once—compared to the Rheem RTG-70XLP-3, which operates at 160,000 BTUs and a 7.0 GPM output, adequate for 2-3 bathrooms but pushing its limits with very high usage.

This distinction is paramount because it directly correlates to how many fixtures can operate concurrently without a noticeable drop in hot water temperature. The Westinghouse Smart Outdoor Propane Tankless Water Heater, with its 180,000 BTU rating and 8.1 GPM, sits in the upper echelon, clearly positioning itself for homes with significant hot water needs. Similarly, the Rheem RTGH Series offers a substantial 157,000 BTU and 8.4 GPM flow rate, designed for robust performance.

Conversely, models like the CAMPLUX Climatech 5 Tankless Water Heater Propane Outdoor, at 5.28 GPM and implicitly lower BTU, are better suited for less demanding applications or single-point usage, like a detached workshop or a seasonal cabin. Even the Noritz EZTR40LP, designed as an indoor tank replacement, focuses on the efficiency of tankless technology rather than raw BTU output for multi-fixture support in the same way as its outdoor, high-BTU counterparts.

The GE Appliances 30 Gallon Electric Water Heater, while a 30-gallon unit, highlights a different heating element entirely, with its capacity dictated by tank size rather than on-demand gas combustion. For those requiring substantial, simultaneous hot water delivery, prioritizing the highest BTU and GPM figures available in liquid propane models, such as the Rheem RTG-84DVLP-3 with its 180,000 BTUs, is the most effective strategy.

How to Choose the Best 40 Gallon LP Water Heater

Hot water delivery capacity gpm and btu output

When selecting a 40-gallon LP water heater, understanding its hot water delivery capacity, measured in gallons per minute (GPM), and its BTU output is paramount for ensuring adequate hot water for your household’s needs. Flow rates can vary significantly, from models like the CAMPLUX Climatech at 5.28 GPM, suitable for smaller demands, up to robust options like the Rheem RTGH Series and Rheem RTG84DVLP3, which offer an impressive 8.4 GPM. This higher GPM is crucial for homes with multiple bathrooms, capable of supporting simultaneous use of showers and laundry, as seen with Rheem RTG models designed for 2-3 bathroom homes.

To heat this water effectively, BTU (British Thermal Unit) output is key. Some units feature BTU outputs as high as 180,000, seen in the Westinghouse Smart Outdoor Propane Tankless or the Rheem RTG84DVLP3, providing powerful on-demand performance for the whole home.

Meanwhile, models like the CAMPLUX Climatech list a BTU output of 105,Matching these specifications to your anticipated usage will prevent lukewarm showers and ensure consistent hot water availability.

Installation location flexibility and type

Consider where your 40-gallon LP water heater will live before you buy, as installation location dictates crucial design factors. Many tankless models, like the Westinghouse Smart Outdoor Propane Tankless Water Heater with its 8.1 GPM flow rate, are specifically engineered for outdoor use only, meaning you’ll need an exterior wall or sheltered space. Similarly, the CAMPLUX Climatech 5 Tankless Water Heater is designed for outdoor propane installation.

Those seeking to replace an existing 40-gallon tank might find a direct fit with the Noritz EZTR40LP, an indoor tank replacement model. Other units offer more adaptability; the MIZUDO Tankless Water Heater Propane is a convertible option, allowing for either indoor or outdoor installation.

If an indoor installation is your only option, ensure the model you choose supports it. For instance, the Rheem RTG-84DVLP-3 is an indoor tankless liquid propane unit, and the Rheem RTGH Series is also designed for indoor placement.

Fuel type and gas input

Most 40-gallon LP water heaters operate on liquid propane, a readily available fuel source for homes not connected to a natural gas line. The Rheem RTG-70XLP-3, for instance, is powered by liquid propane and boasts a robust 160,000 BTUs of gas input, ensuring ample hot water for multiple fixtures simultaneously. Similarly, the Westinghouse Smart Outdoor Propane Tankless Water Heater delivers an impressive 180,000 BTU output.

While liquid propane is the prevalent fuel, it’s worth noting that some tankless models, like the Rheem RTG-70XLN-3, are designed specifically for natural gas and come with a comparable 160,000 BTU input. Understanding your available fuel source is paramount, as using the wrong type can render a unit inoperable or even unsafe.

For those committed to LP, models like the CAMPLUX Climatech 5 and MIZUDO tankless heaters offer efficient propane-powered solutions with varying GPM (gallons per minute) flow rates to match household demand.

Tankless vs tank replacement models

A true 40-gallon hot water heater offers a finite amount of hot water per hour, whereas tankless models provide a continuous supply. For example, the Westinghouse Smart Outdoor Propane Tankless Water Heater boasts an impressive 8.1 GPM (gallons per minute) flow rate, ideal for multiple simultaneous demands, a feat a traditional 40-gallon tank simply cannot match. Similarly, the Rheem RTG-70XLP-3 delivers up to 7.0 GPM, efficiently supporting 2-3 bathrooms.

If you’re specifically replacing an existing 40-gallon unit, the Noritz EZTR40LP is designed as a direct indoor replacement, offering the advantage of endless hot water while fitting into your current setup. Models like the CAMPLUX Climatech and MIZUDO also provide on-demand heating, a stark contrast to the stored capacity of a tank.

This means no more running out of hot water during peak usage times, a significant upgrade from the limitations of a 40-gallon LP model.

Quick Best 40 Gallon Lp Water Heater Buying Checklist

• Fuel Type & Efficiency: Ensure it’s Certified for LP (Liquefied Petroleum) gas and check the Energy Factor (EF) rating – higher is better for lower operating costs.
• BTU Input Rating: Look for models with a BTU input suitable for your household’s peak hot water demand; higher BTUs provide faster recovery.
• Dimensions & Space: Measure your intended installation space carefully; verify the heater’s height, width, and depth, including clearance requirements.
• Ventilation Type: Determine if you need a conventional atmospheric vent, direct vent, or power vent model based on your home’s venting capabilities and safety regulations.
• Warranty Coverage: Examine the length and terms of the manufacturer’s warranty, especially for the tank and internal components, as this indicates product quality.
• Thermostat & Controls: Check for user-friendly temperature controls and safety features like an auto-reset high-temperature cutoff and diagnostic lights.

Frequently Asked Questions

What Are The Key Features To Look For When Choosing The Best 40-Gallon Propane Water Heater For A Home?

The key features for selecting the best 40-gallon propane water heater involve prioritizing its Uniform Energy Factor (UEF) rating for efficiency, ensuring adequate first-hour rating (FHR) for demand, and confirming the venting type (atmospheric, power, or direct vent) suits your home’s installation space and safety requirements. A higher UEF signifies greater energy savings, while an appropriate FHR guarantees sufficient hot water availability.

How Do I Determine The Right Recovery Rate For A 40-Gallon Lp Water Heater Based On My Household’S Hot Water Usage?

To determine the right recovery rate for a 40-gallon LP water heater, consider your household’s peak hour demand. The recovery rate, indicating how quickly the heater can reheat a full tank, should comfortably exceed your highest anticipated hot water usage within a single hour.

Which Brands Of 40-Gallon Propane Water Heaters Are Generally Considered The Most Reliable And Offer Good Value?

For 40-gallon propane water heaters, brands frequently cited for reliability and value include Rheem, AO Smith, and Bradford White. These manufacturers are recognized for their durable construction, efficient performance, and readily available parts, contributing to longevity and lower long-term ownership costs.

Are There Specific Energy Efficiency Standards Or Certifications I Should Prioritize When Buying A 40-Gallon Lp Water Heater?

Yes, prioritizing Energy Factor (EF) ratings is crucial when buying a 40-gallon LP water heater. Look for models with a higher EF, as this metric directly indicates greater energy efficiency and lower operating costs.

Can A 40-Gallon Propane Water Heater Adequately Supply Hot Water For A Family Of Four, And What Factors Influence This?

A 40-gallon propane water heater can often adequately supply hot water for a family of four, but its sufficiency depends on the tank’s recovery rate and the family’s peak demand. The ability to reheat water quickly is crucial for sustained hot water availability during simultaneous uses like showers and laundry.

Final Words

With its ample capacity and efficient operation, a 40-gallon LP water heater is an excellent choice for providing reliable hot water for your household’s needs. This size offers a perfect balance of performance and energy consciousness, ensuring comfort without unnecessary waste. Embrace the dependable warmth and convenience this essential appliance brings to your home, and enjoy consistent hot water for years to come.