The best propane tankless hot water heaters deliver on-demand, endless hot water for households seeking efficiency and space savings. Choosing the right model ensures a consistent supply for RVs, off-grid living, or as a primary home system without the bulk of traditional tanks. Performance varies significantly, impacting flow rate, temperature stability, and ignition reliability.
A poor selection can lead to lukewarm showers, wasted energy, and premature replacement costs. With numerous manufacturers and models available, identifying the ideal unit requires careful consideration of your specific needs and intended usage.
Below, we explore ten top-rated propane tankless water heaters that offer exceptional performance and value, helping you make an informed decision for reliable hot water.
The best propane tankless hot water heaters offer a consistent supply of hot water, with models like the Rinnai V53DeP and Rheem RTG-70XLP-3 providing 5.3 GPM and 7.0 GPM respectively. Standout choices often feature high flow rates, such as the APUS 190,000 BTU outdoor unit at 8.1 GPM, making them suitable for multiple simultaneous hot water demands. Condensing models, like the Rinnai RX199iN and Rheem RTG-95DVLP-3, offer enhanced efficiency with higher BTU ratings, ensuring performance even in colder climates.
Best Propane Tankless Hot Water Heaters: Top Picks Compared
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, Outdoor Installation Best for: Outdoor homes | Check Price |
Best Pick 2  | NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Best for: Smart homes | Check Price |
Best Pick 3  | Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Best for: Mild climates | Check Price |
Best Pick 4  | Rheem RTG-95DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water Best for: Interior homes | Check Price |
Best Pick 5  | Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3 Best for: Standard homes | Check Price |
How We Picked
To determine the best propane tankless hot water heaters, we prioritized real-world performance and build quality. We evaluated GPM (gallons per minute) for adequate hot water supply, essential for busy households, focusing on models like the Rinnai V53DeP and Rheem RTG-70XLP-Durability and safety were paramount, leading us to favor units with robust construction and reliable ignition systems.
Out of the options, we selected those offering a strong balance of these factors and standout features such as smart technology and versatile installation, ensuring long-term value.
What Most Buyers Get Wrong
Understanding GPM for Your Propane Heater
Gallons Per Minute (GPM) is crucial for propane tankless heaters. It dictates how much hot water is available simultaneously. A higher GPM, like the 8.1 GPM from the APUS 190,000 BTU or Westinghouse units, is ideal for large homes with multiple simultaneous demands, such as running a dishwasher and shower.
For smaller needs, a unit like the Rinnai V53DeP at 5.3 GPM might suffice, but always consider peak usage to avoid lukewarm surprises.
Indoor vs. Outdoor Propane Installation Needs
Choosing between indoor and outdoor installation for your propane tankless water heater hinges on venting and space. Outdoor units, like the Rinnai V53DeP and Rheem RTG-70XLP-3, are designed to vent directly outside, simplifying installation and saving interior space. Indoor models, however, may require specialized venting kits, especially for condensing units like the Rheem Liquid Propane Condensing unit.
Always check local codes and ensure proper ventilation for safety and efficiency.
1. Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, Outdoor Installation
Best for: Outdoor installation homes needing 5.3 GPM.
With a 5.3 GPM flow rate, this Rinnai V53DeP outdoor unit provides continuous hot water for multiple demands simultaneously. Its energy-efficient design heats water only when needed, enhancing longevity through improved scale detection. The compact form factor allows for discreet exterior placement.
This wall-mounted unit operates on gas power, delivering 81 Kilowatts of heat output. Its special features include tankless operation, high efficiency, Wi-Fi capability, and enhanced scale detection, ensuring consistent performance and an endless supply of hot water for busy households.
Pros
- 5.3 GPM flow rate for simultaneous use
- Energy-efficient heating on demand
- Improved scale detection for longevity
- Compact, outdoor space-saving design
Cons
- Not smart home compatible, requiring manual adjustments if needed.
Ideal for homeowners seeking reliable outdoor hot water solutions. This Rinnai model is well-suited for those who prioritize continuous hot water supply and energy efficiency in their installation.
2. NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane
Best for: Versatile indoor/outdoor use with smart features.
This Rinnai RX199iN model offers installation flexibility for both indoor and outdoor settings, powered by either propane or natural gas with its Smart Sense system. Its compact, suitcase-sized design belies its capacity to deliver up to 11.1 GPM, supporting up to 7 fixtures at once.
Featuring Smart Sense gas control and the Versa Vent system, this unit boasts 98 watts and 120 volts. It achieves high efficiency with a UEF of .98 and can reach a maximum temperature of 140°F, managing up to 150 PSI safely.
Pros
- Installs indoors or outdoors with Versa Vent
- Uses Smart Sense for propane/natural gas
- Up to 11.1 GPM for 7 fixtures
- Compact suitcase-like dimensions
Cons
- Requires RX-OVC vent cap for outdoor installations.
Perfect for homeowners who need a flexible installation solution for propane or natural gas. This Rinnai unit is designed for households requiring substantial hot water from a compact, smart unit.
3. Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water
Best for: Outdoor, 7 GPM for moderate needs.
Delivering up to 7.0 GPM, this Rheem RTG-70XLP-3 is ideal for 2–3 bathroom homes needing reliable hot water for showers and laundry. Fueled by liquid propane at 160,000 BTUs, this durable unit ensures rapid, consistent hot water during peak usage.
Designed for outdoor wall mounting, it operates on AC/DC power with 132 watts and 120 volts. Key features include hot-start programming for quicker response, compatibility with 1/2 inch gas lines, and industry-leading side-to-side clearance requirements.
Pros
- 7.0 GPM flow rate for 2-3 bathrooms
- 160,000 BTUs of heating power
- Durable metal cabinet for outdoor resilience
- Hot-start programming for faster hot water
Cons
- Limited to outdoor installations only.
This Rheem unit is a strong choice for homeowners with 2 to 3 bathrooms who need a dedicated outdoor hot water solution. It provides dependable performance for simultaneous hot water demands.
4. Rheem RTG-95DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water
Best for: Indoor, 9.5 GPM for large homes.
With a powerful 9.5 GPM flow rate, the Rheem RTG-95DVLP-3 provides ample hot water for 2–3 bathroom homes supporting simultaneous demands like showers and laundry. Its 199,900 BTUs ensure fast, reliable hot water, even during peak household activity.
This indoor-rated unit operates on AC/DC power (132W, 120V) and features an integrated digital display for easy monitoring. It boasts hot-start programming, high energy efficiency, and universal venting compatibility for installation flexibility.
Pros
- 9.5 GPM flow rate for busy households
- 199,900 BTUs for rapid heating
- Integrated digital display for convenience
- Suitable for indoor installation
Cons
- Not smart home compatible, requires manual control.
This Rheem tankless water heater is perfect for larger homes with higher hot water demands, especially those with multiple bathrooms. It’s designed for efficient indoor use and provides consistent performance.
5. Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3
Best for: Indoor, 5.3 GPM for smaller spaces.
The Rinnai RE140iP offers a smart, energy-conserving design that heats water only when needed, suitable for indoor installations. Its clean internal layout speeds installation and enhances serviceability, while the LED screen provides important service reminders and error codes.
This non-condensing unit delivers up to 5.3 GPM, ideal for up to 5 fixtures concurrently. It operates at 140,000 BTU and utilizes 120 volts with 140,000 watts, providing high efficiency in a compact, suitcase-sized form factor ideal for apartments or smaller homes.
Pros
- 5.3 GPM flow rate for up to 5 fixtures
- Energy-saving on-demand heating
- LED display for service alerts
- Compact indoor design
Cons
- Non-condensing unit may be less efficient than condensing models.
This Rinnai heater is an excellent choice for smaller homes or apartments requiring an efficient indoor hot water solution. It balances capacity with a compact design for convenience.
6. APUS Tankless Water Heater Propane Gas, Up to 5.43 GPM,
Best for: 24/7 reliable hot water, low flow start.
This APUS tankless water heater provides a 120,000 BTU heating capacity with a 5.43 GPM flow rate, complemented by innovative 0.66 GPM low-flow start technology. It efficiently meets simultaneous hot water demands for multiple fixtures, maintaining stable temperatures.
Featuring high-precision sensors and smart CPU technology, it ensures precise and steady temperature control up to 140°F. Special features include anti-freezing protection, dry combustion protection, flame failure protection, and an LED display for status monitoring.
Pros
- 5.43 GPM flow rate for multiple fixtures
- 0.66 GPM low-flow start reduces waste
- Smart CPU for precise temperature control
- Multiple safety protections (anti-freeze, overheat)
Cons
- Maximum temperature limited to 140°F.
This APUS unit is ideal for households needing consistent hot water with features that ensure reliability and efficiency. Its low-flow start technology is beneficial for settings with low demand simultaneous use.
7. Rheem Liquid Propane Condensing Tankless Water Heater Indoor Up To
Best for: Condensing, 6.8 GPM for whole-house.
With a flow rate of 0.4 – 6.8 GPM, this Rheem condensing tankless water heater offers efficient whole-house hot water. Its available temperature settings range from 100 to 140°F, with a default of 120°F, ensuring customizable comfort for various household needs.
This fuel-powered unit operates on 120 volts and 132 watts, delivering a high efficiency rating and 120 BTUs of heat output. Special features include hot start programming and overheat film wrap, contributing to its performance and longevity.
Pros
- 6.8 GPM flow rate for whole-house applications
- 100-140°F adjustable temperature range
- High efficiency condensing technology
- Includes hot start programming
Cons
- Covers include only 1 year labor warranty out of three.
This Rheem condensing tankless water heater is designed for homeowners seeking an efficient, high-capacity solution for their entire home. Its adjustable temperature range makes it versatile for various comfort preferences.
8. Rinnai CX199iN Condensing Smart Sense Commercial Natural Gas or Propane
Best for: Commercial/Residential, 11.1 GPM.
The Rinnai CX199iN offers versatility for both commercial and residential use, installable indoors or outdoors with its Versa Vent system. Powered by either propane or natural gas via its Smart Sense gas control system, it supports up to 11.1 GPM, accommodating 7 fixtures simultaneously.
This condensing unit operates at 600 watts and 120 volts, delivering 199,000 BTUs with 96% efficiency. Its maximum temperature reaches 185°F, and it can handle pressures up to 150 PSI, making it suitable for demanding applications.
Pros
- 11.1 GPM flow rate for high-demand use
- Dual fuel compatibility (propane/natural gas)
- Indoor or outdoor installation options
- Smart Sense gas control system
Cons
- Requires RX-OVC vent cap for outdoor installations.
This Rinnai CX199iN is an excellent option for demanding commercial applications or large residential settings. Its ability to handle multiple fixtures and dual fuel types offers significant flexibility.
9. APUS 190,000 BTU Outdoor Tankless Water Heater, 8.1 GPM Propane
Best for: Remote control, app for whole-home.
This APUS 190,000 BTU outdoor tankless water heater delivers 8.1 GPM of instant hot water, perfect for whole-house use. It effortlessly supplies 3 showers and 2 faucets simultaneously, while its ultra-low 0.79 GPM minimum flow ensures reliability even with weak water pressure.
Featuring APP control through Tuya APP and remote control capabilities, you can adjust settings remotely. Its advanced heat exchanger and smart seasonal technology provide efficient operation. The unit handles 120 volts (AC) and delivers up to 149°F maximum temperature.
Pros
- 8.1 GPM flow rate for whole-house demands
- App and remote control capabilities
- Ultra-low 0.79 GPM startup flow
- Smart Seasonal Technology for efficiency
Cons
- Outdoor installation only.
This APUS tankless water heater is perfectly suited for large homes requiring consistent, high-volume hot water, especially when remote control is desired. Its low-pressure startup is a key benefit for areas with inconsistent water flow.
10. Westinghouse Smart Propane Tankless Water Heater Outdoor, 8.1 GPM 180,000
Best for: Outdoor smart control, ±1°F stability.
Designed for outdoor installation, this Westinghouse smart propane tankless water heater delivers up to 8.1 GPM and 180,000 BTU for whole-home on-demand performance. It comfortably supports 3–5 fixtures simultaneously, including showers, sinks, and appliances.
Featuring advanced self-modulating technology, it automatically adjusts gas and water flow to maintain precise ±1°F temperature stability. This unit operates on 120 Volts (AC) and can handle up to 150 PSI, offering easy installation and CSA certification.
Pros
- 8.1 GPM flow rate for 3-5 fixtures
- Precise ±1°F temperature stability
- Outdoor installation friendly
- Remote control functionality
Cons
- Requires AC power, indicated by ‘Is Electric: Yes’.
This Westinghouse unit is an excellent upgrade for homeowners wanting precise temperature control and smart features for their outdoor hot water needs. It’s ideal for families needing simultaneous appliance use without temperature fluctuations.
GPM vs. BTU: The Real Propane Tankless Trade-off
When evaluating the best propane tankless hot water heaters, the single most critical determinant is matching the flow rate (GPM) and heating capacity (BTU) to your peak simultaneous demand. Failing to do so means either lukewarm water when you need it most or an unnecessarily oversized, inefficient unit.
Consider the Rheem RTG-70XLP-3 and the Rheem RTG-95DVLP-While both are Rheem High Efficiency Non-Condensing Outdoor Liquid Propane Water heaters, their GPM ratings tell a story. The RTG-70XLP-3 offers up to 7.0 GPM, suitable for 2-3 bathrooms with moderate usage.
Step up to the RTG-95DVLP-3, and you get a higher 9.5 GPM, powered by a substantially larger 199,900 BTU input. This isn’t just an incremental upgrade; it’s a capacity leap that directly translates to being able to run a high-demand shower and a dishwasher concurrently without a noticeable drop in temperature.
The APUS 190,000 BTU Outdoor Tankless Water Heater, 8.1 GPM Propane, and the Westinghouse Smart Propane Tankless Water Heater Outdoor, 8.1 GPM 180,000, also fall into this higher performance tier. They are designed for households with multiple simultaneous heavy hot water needs, such as large families where showers, laundry, and dishwashing often overlap.
Conversely, units like the Rinnai V53DeP Propane Tankless Water Heater, 5.3 GPM, and the Rinnai RE140iP Non-Condensing Propane Tankless Water Heater, Up to 5.3, are engineered for more modest requirements. Their 5.3 GPM flow rate, generally coupled with lower BTU inputs (often around 120,000 for the APUS Tankless Water Heater Propane Gas, Up to 5.43 GPM), are ample for single-bathroom applications or smaller homes where simultaneous demand is rare. Attempting to push these lower-capacity units beyond their designed limits will inevitably lead to shortcycling, reduced hot water temperature, and dissatisfaction.
The distinction between condensing and non-condensing models, such as the NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane versus the Rheem RTG-70XLP-3, is primarily about energy efficiency and installation location. Condensing units, while often more expensive upfront, recapture heat from exhaust gases for greater fuel efficiency. However, this benefit is secondary to ensuring the fundamental GPM and BTU rating meets your household’s actual peak demand.
For a household prioritizing running multiple high-demand appliances simultaneously, the Rheem RTG-95DVLP-3 offers the necessary capacity without compromise.
What to Look For in Best Propane Tankless Hot Water Heaters
Heating capacity and flow rate
When selecting a propane tankless water heater, prioritize its heating capacity by matching the Gallons Per Minute (GPM) to your household’s demand, especially for simultaneous use. For a 2-bathroom home, aim for a 6.6 GPM unit ensuring a 55°F temperature rise. Homes with 3 or more bathrooms require 8 GPM or higher for uninterrupted hot water.
Look for models explicitly stating their GPM at different temperature rises. A unit with a higher GPM rating at a substantial temperature rise is the optimal choice for consistently meeting your hot water needs across multiple fixtures.
Choose the highest GPM unit your home can support for superior performance and comfort.
Energy efficiency and ignition type
Evaluate energy efficiency by scrutinizing the Energy Factor (EF) rating; higher numbers, typically above 0.8, indicate a more efficient unit that conserves propane. Opt for electronic ignition systems over standing pilot lights, as they only activate the burner when hot water is demanded, leading to significant propane savings. For venting, direct-vent models are superior as they draw combustion air from outside and vent exhaust directly through a wall, making them ideal for indoor installations and maximizing safety.
Choose an electronic ignition, direct-vent model with an EF of 0.85 or higher for the most economical and efficient operation.
Size and installation space
Consider the physical dimensions and installation requirements to ensure a proper fit within your available space. Compact dimensions are crucial for dwellings with limited utility areas. Wall-mounting capabilities are a significant advantage, freeing up floor space and simplifying installation.
Lightweight models reduce the complexity and cost of mounting. For most homes, a unit around 20-30 pounds with a wall-mount bracket is the easiest to install.
Select a unit with compact, wall-mountable dimensions for straightforward installation and space optimization, guaranteeing it fits where you need it without compromise.
Which Should You Choose?
- If you need hot water for a large household with multiple simultaneous demands (showers, laundry, etc.), look for a model with a flow rate of 7.0 GPM or higher.
- If you want the flexibility to install the heater either indoors or outdoors or run it on natural gas or propane, choose a condensing model with versatile venting options.
- If you have limited space or prefer a quieter operation, consider a non-condensing model, especially for outdoor installations.
- If you’re looking for efficient operation and don’t need extreme flow rates, a model designed to heat only when necessary with a flow rate of around 5.3 GPM is a good choice.
Quick Best Propane Tankless Hot Water Heaters Buying Checklist
- Flow Rate: Ensure the GPM meets your household’s simultaneous hot water demands.
- Temperature Rise: Check if the heater can effectively raise water temperature in your climate.
- Venting: Confirm the venting type (direct, natural) is compatible with your installation location.
- Ignition Type: Electronic ignition is generally more efficient than continuous pilot lights.
- Thermostat Control: Look for precise temperature adjustments for consistent hot water.
- Safety Features: Verify built-in safety mechanisms like flame failure protection and overheat shutoff.
Frequently Asked Questions
What Is The Minimum Gpm For A Propane Tankless Water Heater?
The minimum GPM for a propane tankless water heater typically ranges from 4 to 7 GPM. This flow rate is usually sufficient for small homes or apartments with one or two bathrooms, ensuring adequate hot water for basic needs.
Can A Propane Tankless Water Heater Provide Enough Hot Water For Multiple Showers?
Yes, higher-end propane tankless water heaters can provide enough hot water for multiple showers simultaneously. Models with higher GPM ratings and robust temperature rise capabilities are designed to handle significant demand without a drop in hot water.
How Does The Temperature Rise Affect Performance Of Propane Tankless Water Heaters?
Temperature rise indicates how much a propane tankless water heater can increase the incoming water temperature. A higher temperature rise is crucial in colder climates to ensure sufficient hot water output even when the incoming water is very cold.
What Are The Power Requirements For Propane Tankless Water Heaters?
Propane tankless water heaters require electricity to power their electronic ignition and control systems, not for heating the water itself. They typically use standard household outlets, but always check the specific model’s power consumption.
Are Propane Tankless Water Heaters Safe For Indoor Installation?
Many propane tankless water heaters are designed for safe indoor installation, provided they are properly vented. Direct-vent models draw combustion air from outside and exhaust safely outside, making them suitable for different indoor spaces.
Final Words
Investing in one of the best propane tankless hot water heaters offers an efficient and on-demand solution for your home’s hot water needs. These units provide continuous hot water, save energy, and can free up space. Upgrade your system today for consistent comfort and modern convenience.
