12 Tankless Propane Water Heater For Replacing Old Traditional Tank Model of 2026 Without Costly Rework

1

VEVOR Propane Tankless Water Heater, 5.3Gal Outdoor 120000 BTU Instant

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  9.0
• Brand
  VEVOR

Key specs2

Outdoor Exhaust Setup

Eliminates indoor flue ducting by venting directly outside, making it suitable for exterior wall installations where running indoor exhaust pipes is impractical.

Remote Temperature Wiring

32.8 ft wired digital wall controller

Pros & cons42

Pros

• Outdoor-ready design vents straight outside without cutting indoor exhaust pathways
• Delivers 120,000 BTU per hour with standard 3/4-inch NPT plumbing connections
• Included 32.8-foot wired control panel allows indoor temperature management
• Maintains consistent warmth using plus or minus 1 degree Fahrenheit sensor adjustments

Cons

• Outdoor mounting requires exterior wall space and freeze protection precautions
• Listing does not specify minimum activation flow rate for low-demand fixtures

2

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

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  9.6
• Brand
  Rheem

Key specs2

Simultaneous Fixture Capacity

Supports three to four showers simultaneously at 8.4 GPM under a 35-degree temperature rise, powered by a 180,000 BTU burner.

Manufacturer Warranty

15-year heat exchanger, 5-year parts

Pros & cons43

Pros

• Supplies 8.4 GPM at 35-degree rise to support 3 to 4 simultaneous showers
• Non-condensing 180,000 BTU indoor direct vent system replaces large storage tanks
• Backed by a 15-year heat exchanger warranty and 5-year parts warranty
• Precision digital control holds water temperature steady within 1 degree Fahrenheit

Cons

• Requires dedicated direct venting through an exterior wall or roof
• High 180,000 BTU propane demand may require upgrading existing gas supply lines
• Manufacturer specifies that professional installation is required

3

FOGATTI InstaShower 8 Plus RV Tankless Water Heater, Propane On

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  8.9
• Brand
  FOGATTI

Key specs2

RV Cabinet Retrofit

• Fits standard 13 x 13 inch RV cutouts
• Includes 15 x 15 inch exterior door
• Replaces Suburban and Atwood 6-gallon tanks

High-Altitude Capability

Operational up to 9,800 feet

Pros & cons42

Pros

• Direct drop-in replacement for standard 6-gallon RV tanks with a 13x13 inch opening
• High-altitude operating mode maintains steady heating performance up to 9,800 feet
• Staged combustion technology controls flame output to prevent overheating in summer
• Includes an integrated pressure relief valve and a 15x15 inch white access door

Cons

• Replacing a 10-gallon tank requires purchasing a separate 18x18 inch retrofit door
• Maximum flow rate is capped at 2.9 GPM for single-fixture mobile use

4

RVPart Pro RV Tankless Water Heater, Propane, Black Door, Remote,

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  8.5
• Brand
  RVPart Pro

Key specs2

RV Plumbing Protection

Built-in 150 PSI pressure reducing valve

Temperature Setting Range

95°F to 123°F with fault code screen

Pros & cons42

Pros

• Fits 13x13 inch cabinet cutouts with an included 15x15 inch black exterior door
• Runs on 12V DC power with forced exhaust fan and freeze protection
• Built-in 150 PSI pressure reducing valve helps protect sensitive RV plumbing
• Microcomputer controller displays fault codes and adjusts heat from 95 to 123 degrees

Cons

• Altitude capability is rated to 5,000 feet rather than higher mountain passes
• Maximum water flow rate in GPM is not specified in manufacturer data

5

18L Tankless Water Heater Propane with Digital Display 4.76 GPM

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.4
• Brand
  Baococo

Key specs2

Portable Flow Rate

4.76 GPM at 115,425 BTU/hr

Shower Attachment

Comes with a dedicated one-button shower head designed to pause water flow instantly and conserve propane in remote setups.

Pros & cons43

Pros

• Delivers up to 4.76 GPM flow with 115,425 BTU output for portable and cabin setups
• Digital display allows monitoring across an adjustable 17 to 113 degree range
• Built-in safeguards include low-flow ignition lockout and dry combustion shut-off
• Lightweight 12.6-inch square footprint allows easy transport and exterior mounting

Cons

• Maximum setpoint temperature tops out at 113 degrees Fahrenheit
• Listing does not state permanent indoor direct-vent exhaust specifications
• Unit must be drained or protected manually when exposed to freezing cold

6

GASLAND Gasmart C Propane Gas Tankless Water Heater Indoor, Max

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.8
• Brand
  GASLAND

Key specs2

Venting Hardware Included

Packaged with 3-inch exhaust pipe

Household Outlet Support

Generates 5.0 GPM from 113,000 BTUs to serve 3 to 5 domestic water outlets with smart modulation within 1 degree Fahrenheit.

Pros & cons42

Pros

• Supplies up to 5.0 GPM with 113,000 BTU output to serve 3 to 5 water outlets
• Bundles a 3-inch diameter exhaust pipe directly inside the product package
• Standard 3/4-inch NPT plumbing ports match standard residential water lines
• Automatic freeze prevention heats the unit below 41 degrees Fahrenheit when powered

Cons

• Requires an active 120V electrical connection to operate internal freeze protection
• Direct-vent indoor installation requires cutting an exterior wall opening

7

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

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  8.7
• Brand
  Rheem

Key specs2

Zero Indoor Venting

Exterior wall mounting expels combustion gases directly into open air, eliminating the need to cut exhaust flues through walls or ceilings.

Concurrent Shower Rating

2 to 3 simultaneous showers at 7.0 GPM

Pros & cons43

Pros

• Outdoor wall mounting eliminates the labor and cost of indoor vent ducting
• Produces 7.0 GPM at 35-degree rise with 160,000 BTUs for 2 to 3 simultaneous showers
• Durable metal exterior housing withstands outdoor weather while freeing floor area
• Includes a 15-year heat exchanger warranty and 5-year parts warranty from Rheem

Cons

• Exclusively engineered for outdoor installation and cannot be mounted indoors
• High-demand homes running 4 or more fixtures at once may exceed 7.0 GPM capacity
• Manufacturer indicates professional installation is required

8

Rheem RRTGH95DVLP3701178 Rheem RTGH Series 9.5 GPM 199,900 BTU 120

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.1
• Brand
  Rheem

Key specs2

Condensing Thermal Efficiency

0.93 UEF rating

Whole-House Peak Output

Supplies up to 9.5 GPM at a 35-degree rise using 199,900 BTUs to power multiple showers and laundry appliances simultaneously.

Pros & cons43

Pros

• High-capacity 9.5 GPM flow at 199,900 BTU easily supports 3 to 4 simultaneous showers
• Condensing design delivers a 0.93 Uniform Energy Factor for maximum fuel savings
• Meets ultra-low NOx standards for clean indoor residential operation
• Backed by a 15-year heat exchanger warranty and 5-year parts warranty

Cons

• Maximum 199,900 BTU firing rate may necessitate upgrading gas supply line sizing
• Direct-vent condensing installation requires both exhaust piping and a condensate drain
• Substantial 59.88-pound weight requires reinforced wall mounting support

9

FOGATTI RV Tankless Water Heater, with 15 x 15 inches

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  8.4
• Brand
  FOGATTI

Key specs2

RV Door Finish

15 x 15 inch matte black exterior door

High-Altitude Capability

Operational up to 9,800 feet

Pros & cons42

Pros

• Direct drop-in fit for standard 13x13 inch RV openings with a 15x15 inch black door
• High-altitude mode enables stable burner operation up to 9,800 feet elevation
• Staged combustion adjusts flame height to avoid scalding during warm summer runs
• Built-in pressure relief valve and 2-meter remote control simplify operation

Cons

• Peak flow rate of 2.9 GPM is designed for single-fixture RV use
• Replacing a 10-gallon tank cutout requires an optional 18x18 inch door retrofit

10

GASLAND Gasmart E Propane Tankless Gas Water Heater Indoor, Max

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.7
• Brand
  GASLAND

Key specs2

Suitcase-Sized Footprint

14.25 x 14.25 x 24.69 inches

Energy Factor Rating

0.80 UEF

Pros & cons43

Pros

• Generates up to 7.6 GPM using 199,000 BTUs to serve continuous household demands
• High 0.80 UEF rating cuts fuel use by 34 percent compared to standard 50-gallon tanks
• Compact wall-mount design frees floor space in basements and utility closets
• Comes with full one-year replacement protection backed by US customer support

Cons

• High 199,000 BTU burner requires confirming propane gas line supply size
• One-year coverage period is shorter than the multi-year warranties on premium brands
• Venting pipes must be sourced separately to complete indoor wall installation

11

Rheem RTG Series 9.5 GPM Liquid Propane Tankless Water Heater

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.5
• Brand
  Rheem

Key specs2

Exterior High-Flow Capacity

Combines a 9.5 GPM flow rate and 199,900 BTUs with an outdoor cabinet, avoiding complex indoor vent runs while serving 3 to 4 showers.

Zero Indoor Venting

Direct outdoor exhaust, no flue ducting

Pros & cons43

Pros

• Delivers 9.5 GPM at 35-degree rise with 199,900 BTUs to handle 3 to 4 showers at once
• Outdoor cabinet discharges exhaust directly into the air with no flue pipe needed
• Durable metal enclosure protects components outside while recovering indoor space
• Supported by Rheem with a 15-year heat exchanger warranty and 5-year parts warranty

Cons

• Outdoor installation requires freeze precautions and an exterior mounting spot
• Peak 199,900 BTU consumption requires a properly sized propane supply pipe
• Manufacturer specifies that professional installation is required

12

Novieex Propane Gas Tankless Water Heater Up to 4.3 GPM

View on Amazon

• BWP Score

  BWP Score is a ranking system developed by Bestwinterproducts.com. BWP score has no relationship or impact from any manufacturers or sales agent websites. Learn more

  7.2
• Brand
  NOVIEEX

Key specs2

Plumbing Port Dimensions

1/2-inch NPT gas and water connections

Water Temperature Span

95°F to 149°F with ±1°F control

Pros & cons43

Pros

• Delivers up to 4.3 GPM with 100,000 BTUs to run a shower and faucet simultaneously
• Offers a wide temperature adjustment span from 95 to 149 degrees Fahrenheit
• Modulating burner precisely adjusts flame height to prevent unnecessary gas consumption
• Lightweight 19.84-pound profile installs easily in tight closets or laundry areas

Cons

• Uses 1/2-inch NPT connections which may require adapters for 3/4-inch plumbing
• Requires an active 110V to 120V AC electrical receptacle to power internal controls
• Exhaust flue venting components are not detailed and must be verified separately

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

How many gallons per minute (GPM) are required to run multiple fixtures at the same time?

Running simultaneous showers and faucets generally requires a flow rate between 7.0 GPM and 9.5 GPM at a 35°F temperature rise. Units delivering 9.5 GPM utilize 199,900 BTU/hr to provide continuous hot water across an entire household, while 7.0 GPM and 8.4 GPM models handle slightly smaller simultaneous demands. Compact indoor heaters rated at 4.3 GPM with 100,000 BTU or 5.0 GPM with 113,000 BTU comfortably support a single shower alongside a sink faucet. If you have distant bathroom sinks where waiting for hot water is an issue, adding an instant hot water heater under the vanity can supply individual fixtures without pulling volume away from your primary propane unit.

Can an outdoor propane tankless water heater eliminate indoor venting requirements?

Yes, choosing an exterior-mounted propane unit allows combustion exhaust to vent directly outdoors, eliminating the need to cut flue openings through interior walls or ceilings. Exterior models with flow ratings of 7.0 GPM, 9.5 GPM, or 5.3 gallons mount on outside walls and feature a 0.82 Uniform Energy Factor (UEF). These outdoor systems produce up to 199,900 BTUs while keeping all combustion gases outside your living space. Selecting an outdoor model also frees up utility closet floor space previously occupied by a traditional 50-gallon tank, though you must confirm clearance requirements on your exterior wall before mounting.

Will an existing propane supply line deliver enough BTUs for an on-demand unit?

Your existing propane supply line must be verified to confirm it can handle burner outputs between 100,000 BTU and 199,900 BTU/hr. Traditional storage tanks heat water slowly using smaller burners, but tankless systems require immediate fuel delivery to heat incoming cold water instantly. For instance, a 4.3 GPM heater requires 100,000 BTU at a gas rated pressure of 11.24" w.c. (2.8 kPa), while high-capacity units draw up to 199,900 BTU/hr. If your existing line or regulator cannot supply the necessary gas pressure during peak demand, the heater may shut down or produce unexpected cold water fluctuations.

What cutout dimensions and power connections are needed when replacing an RV water heater tank?

Replacing a standard 6-gallon RV storage tank requires a 13 x 13-inch rough opening, a 15 x 15-inch outer door, and a 12V DC power connection. On-demand RV units deliver 60,000 BTU of heat output per minute using an oxygen-free copper heat exchanger and a brushless DC fan. Certain RV models also feature high-altitude modes designed to operate smoothly up to 9,800 feet. If you are preparing your rig for cold-weather adventures alongside a diesel heater for camper travel, check that your 12V battery system has adequate capacity to power the water heater control board and exhaust blower.

What venting and electrical connections are required for an indoor propane tankless heater?

Indoor installations require dedicated exhaust ducting, such as a 3-inch exhaust pipe or a direct-vent system, as well as a 120-volt electrical supply. Non-condensing indoor models rated at 5.0 GPM and 113,000 BTU rely on a 3-inch exhaust pipe, whereas condensing models with a 0.93 UEF utilize direct venting through an exterior wall. Indoor units require 110V to 120V AC electrical power to run internal control boards, digital displays, and essential safety hardware like freeze protection, inlet and outlet thermistors, and overheat cutoff fuses. You cannot vent a tankless propane unit into an old passive chimney or standard atmospheric tank vent.

How do water pipe connections and temperature controls compare to old tank water heaters?

Tankless propane water heaters use standard 1/2-inch NPT or 3/4-inch NPT water connections while offering precise digital temperature regulation rather than a rough mechanical dial. Advanced outdoor units include smart sensors that maintain water temperatures within ±1°F of the selected temperature setting, preventing large swings during use. Replacing an old 50-gallon tank with an on-demand unit that achieves a 0.80 to 0.82 UEF can save up to 34% on energy costs by eliminating standby heat loss. Always check whether your existing hot and cold supply lines match the 1/2-inch or 3/4-inch NPT interfaces before finalizing your installation layout.