11 High Efficiency Propane Tankless Heater To Reduce Utility Bills of 2026 For Continuous Hot Water

1

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

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  9.6
• Brand
  Rheem

Key specs2

Venting Requirement

Requires dedicated direct-vent exhaust and intake piping routed outside, making professional indoor placement essential.

Household Demand Rating

8.4 GPM at 35°F rise (3-4 showers)

Pros & cons43

Pros

• Delivers up to 8.4 GPM at a 35 degree Fahrenheit rise with 180,000 BTU output to support 3 to 4 simultaneous showers
• Features a 0.82 Uniform Energy Factor to cut propane waste compared to continuous storage tanks
• Includes a digital LED control panel for precise adjustments within 1 degree Fahrenheit
• Backed by a 15-year heat exchanger warranty and a 5-year parts warranty

Cons

• Requires dedicated direct-vent piping through the wall or roof for indoor propane operation
• Lacks integrated WiFi connectivity for remote monitoring and temperature scheduling
• Does not reach condensing-level energy efficiency ratings above 0.90 UEF

2

Rheem Liquid Propane Condensing Tankless Water Heater Indoor Up To

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  9.3
• Brand
  Rheem

Key specs2

Condensing Efficiency

0.93 UEF (Ultra-low NOx)

Condensate Management

Extracts latent heat from exhaust gases, requiring a dedicated drain line alongside direct venting.

Pros & cons43

Pros

• Condensing design achieves a 0.93 Uniform Energy Factor to extract maximum heat and lower fuel bills
• High 9.0 GPM flow rate at a 35 degree Fahrenheit rise comfortably powers 3 to 4 showers at once
• Complies with ultra-low NOx standards while burning liquid propane
• Robust 15-year heat exchanger warranty protects the core condensing assembly

Cons

• Heavier indoor unit at nearly 60 pounds requiring reinforced wall mounting
• Condensing operation produces acidic drainage that requires dedicated condensate disposal
• Operates without built-in wireless smart controls

3

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

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  8.7
• Brand
  Rheem

Key specs2

Venting Method

Zero indoor venting needed (Outdoor wall-mount)

Outdoor Protection

Constructed with a weather-resistant metal cabinet and integrated freeze protection to endure exterior conditions.

Pros & cons42

Pros

• Outdoor wall mounting eliminates indoor exhaust vent piping and frees interior utility space
• Provides 7.0 GPM at a 35 degree Fahrenheit rise using 160,000 BTU for 2 to 3 simultaneous showers
• Durable metal cabinet includes built-in freeze and flame failure protection for outdoor weather
• Delivers reliable 0.82 UEF efficiency without standby tank reheating loss

Cons

• Outdoor installation exposes plumbing to freezing temperatures if power or freeze protection fails
• Lower 160,000 BTU burner output delivers less volume than larger 180,000 BTU heaters

4

CAMPLUX Climatech 3 Tankless Water Heater Propane 3.6 GPM, 82,000

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  7.4
• Brand
  CAMPLUX ENJOY OUTDOOR LIFE

Key specs2

Connection Sizing

• 1/2-inch NPT gas inlet
• 3/4-inch NPT water connections
• 3-inch outer diameter exhaust vent
• Standard 120V electrical plug

Freeze Activation Threshold

Automatic protection below 39°F

Pros & cons42

Pros

• Compact 20.5-pound profile fits easily into tight utility closets and small apartments
• Operates on 82,000 BTU to supply up to 3.6 GPM for smaller homes and 1 to 2 simultaneous points
• Uses a standard 120V plug and 1/2-inch NPT gas inlet for flexible residential hookups
• Automatically engages freeze protection when ambient temperatures drop below 39 degrees Fahrenheit

Cons

• Flow rate of 3.6 GPM limits use in large multi-bath households during high simultaneous demand
• Vent kit VP70T and service valves are sold separately rather than included in the box

5

Rheem High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Heater,

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  8.6
• Brand
  Rheem

Key specs2

Outdoor Capacity

8.4 GPM at 35°F rise (180,000 BTU)

Vent Infrastructure Savings

Exterior wall-hung design avoids the cost and labor of cutting vent penetrations through roofs or finished walls.

Pros & cons42

Pros

• Mounts outside to eliminate expensive interior vent kits while delivering a high 8.4 GPM capacity
• Supplies 180,000 BTU to effortlessly support 3 to 4 simultaneous hot water points
• Weather-resistant metal enclosure protects core heating elements from outdoor exposure
• Features a 15-year heat exchanger warranty backed by CSA safety certification

Cons

• Must be installed outdoors, requiring accessible exterior gas lines and electrical outlets
• Non-condensing 0.82 UEF does not match the fuel extraction of condensing units

6

Westinghouse Tankless Water Heater Propane Outdoor, 8.1 GPM, 180,000 BTU

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  7.8
• Brand
  Westinghouse

Key specs2

Water Temperature Control

95°F to 158°F via wired remote

Modulation Technology

Uses self-modulating gas-water linkage to maintain water output within 1 degree Fahrenheit of the target setting.

Pros & cons42

Pros

• Supplies up to 8.1 GPM and 180,000 BTU to run 3 to 5 plumbing fixtures at once
• Includes a wired digital remote controller with an adjustable temperature range of 95 to 158 degrees Fahrenheit
• Self-modulating water-gas linkage automatically matches propane burner output to water demand
• Variable-speed combustion fan and outdoor freeze protection ensure reliable cold-weather operation

Cons

• Heat exchanger warranty coverage is limited to 5 years compared to 15 years on competing units
• Requires outdoor mounting with 120V power and accessible 3/4-inch plumbing lines

7

Rheem RTGH Series 6.8 GPM Liquid Propane Tankless Water Heater

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  7.6
• Brand
  Rheem

Key specs2

Fuel Efficiency Rating

0.93 UEF Condensing

Target Household Scale

Optimized for homes needing 2 to 3 simultaneous hot water taps without burning excessive propane.

Pros & cons42

Pros

• Condensing technology achieves an ultra-high 0.93 UEF to minimize propane consumption and utility bills
• Efficient 120,000 BTU burner provides 6.8 GPM at a 35 degree Fahrenheit rise for 2 to 3 showers
• Ultra-low NOx burner produces cleaner exhaust emissions inside residential settings
• Backed by Rheem with a 15-year heat exchanger warranty and 5-year parts warranty

Cons

• Maximum 120,000 BTU output may struggle in colder regions with freezing incoming groundwater
• Requires direct venting and proper condensate drainage piping during indoor installation

8

Rheem RTG Series 9.5 GPM Liquid Propane Tankless Water Heater

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  7.5
• Brand
  Rheem

Key specs2

Peak Flow Performance

9.5 GPM at 35°F rise (199,900 BTU)

Gas Supply Requirement

High 199,900 BTU rating demands verifying adequate propane supply lines and regulator capacity before setup.

Pros & cons42

Pros

• Massive 199,900 BTU output delivers 9.5 GPM at a 35 degree Fahrenheit rise for large households
• Outdoor installation avoids complex indoor vent pipe routing through ceilings or walls
• Handles multiple high-flow demands like simultaneous showers and laundry without temperature drops
• Metal exterior housing includes freeze protection and flame failure sensors for peace of mind

Cons

• Non-condensing 0.82 UEF burns more fuel at peak demand than a 0.93 UEF condensing heater
• Demands an adequate propane gas line volume capable of supplying nearly 200,000 BTU per hour

9

Novieex Propane Gas Tankless Water Heater Up to 4.3 GPM

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  7.2
• Brand
  NOVIEEX

Key specs2

Gas Pressure Specification

11.24 in w.c. (2.8 kPa) rated pressure

Plumbing Interface

• 1/2-inch NPT gas inlet
• 1/2-inch NPT water inlet and outlet
• 110V-120V AC electrical connection

Pros & cons42

Pros

• Delivers up to 4.3 GPM with 100,000 BTU to support a shower and sink simultaneously
• Sectional burner system adjusts the propane flame dynamically to avoid wasting gas on small flows
• Modern LED touchscreen allows precise temperature settings between 95 and 149 degrees Fahrenheit
• Operates across a wide water pressure range from 1.5 psi up to 116 psi

Cons

• Uses 1/2-inch NPT plumbing fittings which may require adapters for standard 3/4-inch household pipe
• Indoor venting pipes and intake materials are not bundled and must be planned separately

10

Novieex Propane Gas Tankless Water Heater Up to 4.75 GPM

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  8.5
• Brand
  NOVIEEX

Key specs2

Water Operating Pressure

1.5 to 116 psi (0.01 to 0.8 MPa)

Burner Modulation System

Sectional burner stages heating zones based on water flow rate to maintain temperature without wasting gas.

Pros & cons42

Pros

• Provides up to 4.75 GPM using a 120,000 BTU burner for simultaneous bathroom and kitchen use
• Built-in sectional burner modulates flame height to match hot water demand and trim propane bills
• Digital touchscreen interface gives clear readout and ±1 degree Fahrenheit thermostat adjustments
• Compact 28-pound wall-mount chassis saves over 50 percent of floor space versus standard tanks

Cons

• All connections use 1/2-inch NPT threads, requiring adaptors if tying into 3/4-inch plumbing runs
• Specific exhaust venting components must be verified and acquired prior to indoor setup

11

Propane Tankless Water Heater with Vent Pipe, Up to 4.3

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  8.5
• Brand
  QERPRE

Key specs2

Included Venting

Dedicated exhaust pipe included in box

Operating Modes

• 4-Season Mode for seasonal climate tracking
• Kitchen Mode preset to 100°F
• Bathtub Mode with alert notification

Pros & cons42

Pros

• Includes a dedicated exhaust vent pipe in the box to simplify indoor installation setup
• Features a four-sectional burner with micro-flame combustion to cut propane use and operating noise
• Offers specialized operation modes including an automated 4-Season Mode and a 100-degree Kitchen Mode
• Built with an oxygen-free copper heat exchanger designed for rapid and efficient heat transfer

Cons

• Water and gas ports are 1/2-inch NPT rather than larger 3/4-inch commercial standard lines
• Flow rate of 4.3 GPM will reduce under severe winter groundwater conditions

Last update on 2026-10-11 / Affiliate links / Images, Product Titles, and Product Highlights from Amazon Product Advertising API

How much energy can a high-efficiency propane tankless water heater save compared to a storage tank?

Switching to a non-condensing propane tankless model with a 0.82 Uniform Energy Factor (UEF) can save up to 34% on energy costs compared to a traditional 50-gallon electric storage tank. Standard storage tanks constantly burn fuel to keep water hot throughout the day, creating continuous standby heat loss. Tankless systems heat water strictly on demand, and condensing designs push efficiency further with ratings up to 0.93 UEF to minimize fuel usage during active operation.

What is the difference between a 0.93 UEF condensing heater and a 0.82 UEF non-condensing heater?

The primary difference centers on heat exchange efficiency, burner output, and exhaust management. Condensing models achieve a 0.93 UEF by capturing extra heat from combustion gases, operating with ultra-low NOx emissions and burner ratings between 120,000 BTU/hr and 180,000 BTU/hr for indoor direct-vent installations. Non-condensing models carry a 0.82 UEF rating across capacities up to 199,900 BTU, delivering continuous hot water with slightly higher exhaust temperatures that dictate specific venting layouts.

What flow rate in GPM is required to run multiple fixtures simultaneously?

Your required gallons per minute (GPM) depends on how many fixtures you use at once and the required temperature rise. Compact units producing 3.6 GPM at 82,000 BTU or 4.3 GPM to 4.75 GPM at 100,000 to 120,000 BTU are rated to supply two to three fixtures simultaneously, such as a shower and a sink. For whole-home demand with multiple showers running at once, higher-capacity models deliver 6.8 GPM, 7.0 GPM, 8.4 GPM, 9.0 GPM, or up to 9.5 GPM based on a 35°F temperature rise. If you have an isolated bathroom or remote sink that demands immediate flow without taxing your central unit, pairing a whole-house setup with an instant hot water heater under the cabinet can solve localized delays.

Should you install an indoor direct-vent unit or an outdoor wall-mounted heater?

Outdoor wall-mounted units eliminate indoor exhaust piping entirely by venting directly into the open air. Outdoor models delivering between 7.0 GPM and 9.5 GPM free up indoor utility space and remove the expense of indoor venting materials. Indoor models are necessary in regions where freezing outdoor temperatures would damage exposed plumbing, requiring direct-vent configurations or dedicated exhaust piping, such as a 3-inch outer diameter vent pipe, to discharge combustion air safely outside.

What gas line size and propane pressure does a tankless unit require?

Propane tankless heaters require adequate gas volume to support high-output burners without causing fuel starvation. Compact models between 82,000 BTU and 120,000 BTU generally utilize a 1/2-inch NPT gas inlet and specify a rated gas pressure of 11.24 inches water column (2.8 kPa). Larger whole-house burners reaching up to 199,900 BTU consume significantly more fuel per hour, so you must verify your existing supply line diameter and regulator capacity to confirm your tank setup can maintain proper operating pressure.

How do tankless propane units prevent sudden temperature drops during showers?

Temperature drops and cold bursts are prevented by self-modulating water-gas linkage systems. These controls continuously monitor incoming water flow and adjust the burner flame in real time to match demand. Units equipped with self-modulating temperature controls hold the water temperature stable within plus or minus 1°F, ensuring that opening a kitchen faucet or running an appliance does not cause an unexpected chill in the shower.