The best 40 gallon LP water heater delivers consistent hot water and reliable performance for homes relying on propane. Choosing the right model ensures comfort and efficiency, preventing wasted energy and frustrating delays. Key variations include energy efficiency ratings, venting types, and specialized features like powered ventilation or electronic ignition, all impacting long-term operational costs and ease of use.
Selecting a unit that perfectly matches your household’s demand and installation constraints is crucial to avoid underperforming or unnecessarily expensive options. Explore our curated list to find the top models that excel in dependability and heating capacity for your needs.
For the best 40 gallon LP water heater, consider a tankless propane model like the Rheem RTG-84DVLP-3, which offers high GPM output for multiple simultaneous uses and 180,000 BTUs. If a direct tank replacement is preferred, the Noritz EZTR40LP provides an indoor tankless solution for the 40-gallon footprint.
Best 40 Gallon LP Water Heater, at a Glance
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000 Best for: Smart homes | Check Price |
Best Pick 2  | Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Best for: Outdoor propane | Check Price |
Best Pick 3  | Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Best for: Natural gas | 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
We prioritized build quality, real-world performance, safety, durability, and standout features when selecting the best 40 gallon LP water heater. Tankless models like the Westinghouse and Rheem RTGH84DVLN3701171 impressed with their high GPM and BTU outputs, offering endless hot water. We ruled out units reliant solely on natural gas or those with significantly lower flow rates.
The Noritz EZTR40LP’s direct tank replacement capability was a noteworthy feature, though direct comparison to true tankless models was challenging. Ultimately, robust construction and consistent, powerful heating were paramount.
What Most Buyers Get Wrong
Tankless vs. 40-Gallon Tanks: The Real Trade-Off
When considering a 40-gallon LP water heater, you’re likely choosing between a traditional tank model and a tankless system. While traditional tanks offer a set amount of hot water, tankless heaters like the Noritz EZTR40LP provide continuous hot water on demand. This means you won’t run out during peak usage, but tankless units have a flow rate limit.
For a 40-gallon equivalent, ensure the tankless GPM (gallons per minute) is sufficient for your household size and appliance needs, similar to how the Westinghouse Smart Outdoor Propane Tankless Water Heater offers 8.1 GPM.
Understanding LP vs. Natural Gas for Your Home
This roundup focuses on Liquid Propane (LP) water heaters, crucial if your home isn’t connected to a natural gas line. LP models, like the Rheem RTG-70XLP-3, rely on propane tanks and offer flexibility in placement. Natural gas models, such as the Rheem RTG-70DVLN-3, require a gas line.
If you’re unsure which fuel source is best for your situation, consult with a professional to determine the most efficient and practical option for your property and local infrastructure before investing in units like the CAMPLUX Climatech 5 or MIZUDO tankless heaters.
1. Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000
Best for: Most fixtures supported, whole-home hot water.
Delivering 8.1 GPM and 180,000 BTU, this outdoor propane tankless unit provides on-demand hot water for up to 5 fixtures simultaneously, ensuring no one waits for a hot shower or laundry cycle.
Its high flow rate supports showers, sinks, dishwashers, and laundry appliances, while precise ±1°F temperature control adds consistent comfort. This wall-mounted gas-powered heater operates using 120 volts with a maximum pressure of 150 PSI.
Pros
- 8.1 GPM flow rate for multiple simultaneous uses
- 180,000 BTU heat output for powerful performance
- ±1°F temperature stability for consistent comfort
- CSA-Certificated for safety assurance
Cons
- Requires outdoor installation only
Ideal for larger homes or properties needing to supply hot water to many points at once. This outdoor solution ensures ample hot water 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.
With 7.0 GPM and 160,000 BTUs, this outdoor tankless liquid propane heater offers high-efficiency performance suitable for homes with 2–3 bathrooms demanding reliable hot water during peak times.
This unit supports busy households with needs like simultaneous showers and laundry, powered by liquid propane for fast, consistent results. It’s designed for wall mounting with a durable metal cabinet and features hot-start programming for quicker hot water delivery.
Pros
- 7.0 GPM flow rate for moderate use
- 160,000 BTU heat output for strong performance
- Hot-start programming for faster hot water
- Designed for outdoor wall mounting
Cons
- Requires 132 watts of power
Best for homeowners prioritizing efficiency and reliable hot water in 2-3 bathroom residences. This outdoor unit ensures consistent performance during high demand.
3. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water
Best for: Natural gas outdoor tankless for 2-3 bathrooms.
Delivering 7.0 GPM and 160,000 BTUs, this high-efficiency tankless natural gas heater is tailored for homes with 2–3 bathrooms, providing rapid hot water for showers and laundry rooms.
This unit powers through peak demand, ensuring continuous hot water with its robust BTU output, and features a self-diagnostic program for ease of monitoring. Designed for outdoor installation, it offers freeze protection and a low activation flow rate for efficiency.
Pros
- 7.0 GPM flow rate for moderate use
- 160,000 BTU heat output for robust performance
- Freeze protection for colder climates
- Low activation flow rate for efficiency
Cons
- Natural gas power source only
Suitable for homes using natural gas needing dependable hot water for up to three bathrooms. This outdoor installer-friendly unit offers consistent performance and smart features.
4. Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater
Best for: Direct 40-gallon tank replacement, indoor tankless.
This indoor tankless water heater acts as a direct replacement for a 40-gallon tank, offering endless hot water without the space constraints of traditional tanks.
With a flow rate of 6.6 GPM, it provides continuous hot water for household needs, efficiently meeting demand while maintaining a compact footprint. The unit is designed for indoor installation and features high efficiency.
Pros
- Endless hot water supply
- Direct 40-gallon tank replacement
- High efficiency operation
- Space-saving indoor design
Cons
- Specific power source not detailed
Perfect for homeowners looking to upgrade from a standard 40-gallon tank without sacrificing hot water availability. This indoor tankless unit offers a modern, efficient solution.
5. Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water
Best for: Indoor natural gas tankless with digital display.
Featuring an integrated digital display, this high-efficiency indoor tankless natural gas water heater delivers up to 7.0 GPM, perfect for 2–3 bathroom homes with multiple hot water demands.
Powered by natural gas with 160,000 BTUs, it ensures fast, reliable hot water with hot-start programming for immediate availability. This durable, compact unit supports easy wall mounting and offers universal venting compatibility.
Pros
- 7.0 GPM flow rate for multiple fixtures
- 160,000 BTU heat output for robust performance
- Integrated digital display for easy monitoring
- Universal venting compatibility for flexible installation
Cons
- Not Smart Home Compatible
Ideal for families in 2-3 bathroom homes using natural gas who desire quick, consistent hot water indoors. The digital display and compact design offer added convenience.
6. CAMPLUX Climatech 5 Tankless Water Heater Propane Outdoor, 5.28 GPM
Best for: Outdoor propane with anti-freezing for 3-5 points.
This outdoor tankless propane water heater delivers up to 6.4 GPM, providing instant hot water on demand for 3-5 simultaneous water points like bathrooms and laundry rooms.
With a heat output of 150,000 BTU per hour, it ensures comfortable water temperatures for various uses. The unit features anti-freezing protection, dry combustion protection, and high water pressure protection for durability and safety.
Pros
- 6.4 GPM flow rate for multiple simultaneous uses
- 150,000 BTU heat output for efficient heating
- Anti-freezing protection for cold climates
- CSA Certified for safety and quality
Cons
- Requires 120 Volts (AC) power
Suitable for outdoor installation needing hot water at multiple points, such as cabins or workshops with 3-5 fixtures. This propane unit offers robust safety features and on-demand performance.
7. MIZUDO Tankless Water Heater Propane, Indoor or Outdoor Convertible Installation,
Best for: Wi-Fi controlled indoor/outdoor propane tankless.
Offering flexible indoor or outdoor installation and smart WiFi control, this propane tankless water heater provides instant hot water with a flow rate of 5.1 GPM, manageable via a mobile app.
With a heat output of 120,000 BTU, it supports 2 to 4 usage points, and its automatic anti-freeze protection ensures reliable operation. Users can adjust temperature settings and monitor energy usage remotely through the dedicated app.
Pros
- 5.1 GPM flow rate for moderate use
- 120,000 BTU heat output for efficient heating
- Smart WiFi and App control for remote management
- Indoor/Outdoor convertible installation flexibility
Cons
- Accessory kits required for installation flexibility
Ideal for tech-savvy homeowners seeking flexible installation and remote control over their hot water. This propane tankless unit is great for managing comfort and energy usage.
8. Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120
Best for: High flow rate indoor propane tankless.
Delivering an impressive flow rate of 8.4 GPM, this indoor tankless unit provides 157,000 BTUs of heating power, ensuring ample hot water for demanding households with multiple simultaneous needs.
With available temperature settings from 100 to 140°F, it accommodates various preferences, featuring an electric ignition for straightforward operation. The unit is covered by manufacturer warranties for parts and heat exchanger.
Pros
- 8.4 GPM flow rate for high demand
- 157,000 BTU heat output for powerful heating
- Electric ignition for easy start-up
- Adjustable temperature settings from 100-140°F
Cons
- Requires 120 Volts power
Best for large families or homes with high hot water consumption requiring a powerful indoor solution. This unit ensures immediate hot water availability for all needs.
9. Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water
Best for: High-efficiency indoor propane for 2-3 bathrooms.
This high-efficiency indoor liquid propane tankless water heater delivers 8.4 GPM with 180,000 BTUs, ideal for 2–3 bathroom homes needing fast, reliable hot water during peak household demand.
Featuring LeakGuard Leak Detection and Prevention, this durable unit ensures safety and efficiency. It supports easy wall mounting by a qualified installer and provides consistent hot water for showers and laundry appliances.
Pros
- 8.4 GPM flow rate for major use
- 180,000 BTU heat output for maximum performance
- LeakGuard Leak Detection for safety
- Designed for indoor wall mounting
Cons
- Requires 132 watts of power
Perfect for larger homes using liquid propane that require a high-capacity indoor hot water solution. This unit offers robust performance and safety features for busy households.
10. GE Appliances 30 Gallon Electric Water Heater with Adjustable Thermostat,
Best for: 30-gallon electric with quick recovery, 1-3 persons.
This 30-gallon electric water heater provides a real 30 gallons of hot water, delivering 53 gallons in the first hour for households of 1 to 3 persons.
With a 5500-watt heating element and 240-volt power, this unit offers quick recovery to ensure hot water availability. It features an adjustable thermostat up to 150 degrees Fahrenheit and a maximum pressure of 125 PSI.
Pros
- True 30-gallon capacity for maximum showers
- 53 gallons First Hour Rating for ample hot water
- Quick Recovery ensures less waiting
- Adjustable thermostat up to 150°F
Cons
- Floor mount type requires specific installation space
Best for smaller households (1-3 people) needing dependable hot water with quick recovery for their daily needs. This electric heater provides efficient hot water for apartments or smaller homes.
Gas Type and Installation Location Overrule All Else
When selecting a best 40 gallon lp water heater, the single most impactful, non-negotiable factor is your existing utility infrastructure combined with intended placement: indoor vs. outdoor. Trying to retrofit a natural gas unit like the Rheem RTG-70XLN-3 or Rheem RTG-84DVLP-3, which uses entirely different gas lines and venting, is a fool’s errand compared to the direct propane solution.
Similarly, while units like the MIZUDO Tankless Water Heater Propane, Indoor or Outdoor Convertible Installation, offer flexibility, the decision point of where it will physically reside dictates whether you prioritize an outdoor-specific model like the Westinghouse Smart Outdoor Propane Tankless Water Heater, 8.1 GPM 180,000, or an indoor-rated unit. Attempting to force a solution into the wrong environment leads to costly modifications or outright failure to operate safely and efficiently.
The discrepancy between liquid propane (LP) and natural gas (NG) is fundamental. The Rheem RTG-70XLN-3, for instance, is a natural gas unit requiring the appropriate supply and ventilation. The Rheem RTG-84DVLP-3, on the other hand, is designed for liquid propane and operates on a different gas pressure and with a different delivery system.
This isn’t merely a matter of preference; it’s a matter of compatibility with your home’s fuel source. For LP users, the choice is narrowed to those explicitly designed for it, eliminating a host of otherwise capable natural gas models.
This fundamental distinction between fuel types is the first and most critical filter, rendering many otherwise attractive options irrelevant from the outset.
Following gas type and installation location, the primary differentiator among the remaining propane options is the GPM (gallons per minute) and BTU (British Thermal Unit) output. While the CAMPLUX Climatech 5 Tankless Water Heater Propane Outdoor offers up to 6.4 GPM, it might struggle with simultaneous high demand compared to the Westinghouse Smart Outdoor Propane Tankless Water Heater at 8.1 GPM or the Rheem RTG-84DVLP-3 at 8.4 GPM. These higher flow rates, coupled with higher BTU ratings like the 180,000 BTU of the Westinghouse unit, translate directly to the ability to serve multiple fixtures at once without a noticeable drop in hot water temperature.
A family needing to run a shower, dishwasher, and washing machine concurrently will find the 5.28 GPM CAMPLUX unit strained, whereas the higher-output Rheem and Westinghouse models are engineered for this higher load.
For those replacing an existing tanked unit, the Noritz EZTR40LP 40 gal Tank Replacement Indoor Tankless Water Heater offers a specific advantage in installation convenience due to its design as a direct swap. However, for most users prioritizing pure performance and flexibility within the propane realm, understanding the interplay between indoor/outdoor installation and the availability of LP fuel is paramount. The Rheem RTG-84DVLP-3 is an excellent choice for larger propane households needing high simultaneous flow.
How to Choose the Best 40 Gallon LP Water Heater
Energy efficiency ratings
When evaluating energy efficiency for your 40-gallon LP water heater, focus on the Uniform Energy Factor (UEF) rating. Higher UEF scores equate to greater efficiency, meaning less energy wasted. Look for models with UEF ratings above 0.60, indicating superior performance.
Gas input capacity, measured in BTUs per hour (BTUH), should align with your household’s demand; a range of 40,000 to 50,000 BTUH is typical for this size. The First Hour Rating (FHR) is crucial for peak usage; aim for an FHR of at least 70 gallons.
Low standby loss, ideally below 5%, is also a key indicator of an efficient unit. For optimal savings and consistent hot water, select a model with the highest UEF and FHR within your budgetary constraints.
Ignition systems
The ignition system significantly impacts ease of use and reliability for your LP water heater. Electronic ignition is the most convenient, eliminating the need for a constantly burning pilot light and saving fuel. Intermittent pilot ignition systems are a good compromise, igniting only when hot water is needed, offering better efficiency than standing pilots.
Standing pilot ignition, while simple, is the least efficient as it continuously burns gas. For maximum fuel savings and user convenience, an electronic ignition system is the preferred choice.
It offers a modern user experience and is generally more reliable over time compared to older pilot light technologies.
Ventilation requirements
Understanding ventilation is paramount for safe and efficient operation of your 40-gallon LP water heater. Directvent systems pull combustion air from outside and vent exhaust gases directly through the wall, offering flexibility in installation location and enhanced safety by isolating combustion. Powerventing uses a fan to assist exhaust, allowing for longer vent runs and installation in more varied spaces.
Natural vent systems rely on the natural buoyancy of hot gases to rise and exit through a vertical flue, requiring a clear path to the outdoors and specific clearances. For most modern installations demanding flexibility and safety, a directvent or powervent system is the superior option, ensuring proper air exchange and exhaust removal.
Physical dimensions and capacity
Beyond its 40-gallon capacity, consider the physical dimensions and construction of your LP water heater. Height and diameter (typically around 20-22 inches wide and 50-60 inches tall for a 40-gallon tank) are important for fitting into your installation space. The tank’s material is critical for longevity; stainless steel or glass-lined steel tanks offer superior corrosion resistance.
Water recovery rates, indicated by the BTUH input, determine how quickly the tank reheats after use. Look for models with adequately sized components and durable tank linings.
For long-term value and reliable performance, a model with a robust, corrosion-resistant tank and a sufficient gas input to ensure quick recovery is recommended.
Which Should You Choose?
- If you need to replace an existing 40-gallon tank heater and want endless hot water with minimal installation hassle, look for an indoor tankless unit designed as a direct replacement.
- If you have multiple bathrooms and frequent high hot water demand (like running laundry and showers simultaneously), choose a high-flow rate (7.0 GPM or higher) propane tankless water heater for continuous hot water.
- If you have limited indoor space or prefer to keep water heating equipment outside, opt for an outdoor-rated propane tankless water heater.
- If you’re looking for a versatile installation option, either indoors or outdoors, select a convertible tankless water heater.
Quick Best 40 Gallon Lp Water Heater Buying Checklist
- Check Energy Factor: Look for a Uniform Energy Factor (UEF) rating to understand its efficiency.
- Verify Venting Type: Ensure the chosen model’s venting system (direct, power, or natural) is compatible with your installation space.
- Consider Ignition Type: Electronic ignition offers convenience, while intermittent pilots can save energy compared to standing pilots.
- Review Dimensions: Measure your available space to confirm the physical dimensions will fit.
- Assess Recovery Rate: Understand how quickly the heater can replenish hot water for your household needs.
- Check Warranty: Review the manufacturer’s warranty for peace of mind.
Frequently Asked Questions
What Is The Typical Temperature Range For A 40-Gallon Lp Water Heater?
Most 40-gallon LP water heaters allow users to adjust the temperature between 100°F and 140°F. This range ensures sufficient hot water for various household needs, from daily showers to dishwashing, while also providing safety to prevent scalding.
How Do I Ensure Proper Ventilation For A 40-Gallon Lp Water Heater?
Proper ventilation is crucial for safety and performance, preventing carbon monoxide buildup. Ensure the chosen model’s venting system, whether direct, power, or natural, is installed according to manufacturer guidelines and local codes to exhaust fumes safely.
What Is The Uniform Energy Factor (Uef) For A 40-Gallon Lp Water Heater?
The Uniform Energy Factor (UEF) measures the energy efficiency of a 40-gallon LP water heater, with higher numbers indicating greater efficiency. Models typically range from 0.59 to over 0.70 UEF, impacting fuel consumption and operating costs.
How Does Ignition Type Affect A 40-Gallon Lp Water Heater?
Ignition type influences efficiency and convenience. Electronic ignition offers automatic activation, while intermittent pilot lights save gas when the heater isn’t in use. Standing pilot lights offer simplicity but consume fuel constantly.
What Is The First Hour Rating (Fhr) Of A 40-Gallon Lp Water Heater?
The First Hour Rating (FHR) indicates how much hot water a fully heated 40-gallon LP water heater can deliver in the first hour of use. This metric is vital for households with high simultaneous hot water demands, like multiple showers.
Final Words
Investing in the best 40 gallon LP water heater provides reliable hot water for your home, offering crucial energy efficiency and convenience. These units ensure you always have the hot water you need for daily tasks without excessive fuel consumption. Make an informed choice today to enhance your home’s comfort and performance.