Buying guide · 10 min read · Updated October 2, 2026

4 Best RV Tankless Water Heater With Mixing Tank in 2026: A Practical RV Guide

Best RV tankless water heaters with a built-in mixing tank compared on buffer design, flow claims, certifications and door fit.

By Bowen HigginsRV Editor at RV Gear Lab4 products comparedSpec-sheet researched

A built-in mixing tank buffers the temperature swings that make cheap tankless showers go hot then cold. This shortlist compares four 65,000 BTU-class propane heaters that describe a mixing tank or chamber in their own listings.

Each heater was read for how it describes the buffer, claimed flow and altitude rating, certifications and door fit. GPM claims depend on temperature rise and are reported as listing claims.

RV Gear Lab field notes

The Rig Fit Check

Start with the job: CAMPLUX RV Tankless Water Heater leads this shortlist for Boondockers. Use that fit as a reference point, then compare the alternatives against your own space and workload.
Specs that separate the picks: The first details to compare are Built-in mixing tank, Thermostatic mixing chamber, 16.9 oz mixing tank. Confirm the exact model and included components before ordering.
Trade-off to plan for: Needs 12V power

Before you buy

What Matters Before You Choose an RV Tankless Water Heater With Mixing Tank

Key buying criteria so you get the right fit the first time.

01
Why a mixing tank
A small buffer smooths temperature swings when flow or inlet temperature changes. It matters for comfortable showers. Look for a stated tank volume.
02
Mixing tank vs chamber
A physical 16.9 oz tank and a thermostatic chamber work differently. It matters for how steady output stays. Read each description.
03
Low-flow startup
A low minimum flow saves propane and water. It matters when boondocking. Look for 0.5 GPM.
04
Certifications
CSA covers appliance safety, and NSF covers water-contact materials. It matters for safe use. Read which is listed.
05
Opening size
12.8 or 13 inch openings suit retrofits. It matters for fit. Measure first.

Our standards

Why You Can Trust RV Gear Lab

At RV Gear Lab, we compare products based on rig fit and power or hookup compatibility, verified specifications, usability, setup requirements, weight, durability, and real-world trade-offs. We do not rank products purely on marketing claims or commission rates.

We have not personally tested every product listed. Where hands-on testing is not available, recommendations are based on verified manufacturer specifications, product documentation, use-case fit, and comparative research.

How we review RV gear →

Detailed reviews

The 4 best rv tankless water heater with mixing tank, explained

Best Low-Flow Startup · 1 of 4

CAMPLUX RV Tankless Water Heater

Built-in mixing tank
0.5 GPM startup
CSA and NSF certified

Check price on Amazon

Best for: Boondockers

Our take

Best for boondockers who want low-flow ignition and a certified buffer.

Why it made the shortlist

The CAMPLUX RV Tankless Water Heater is a 65,000 BTU propane unit with a built-in mixing tank, a multi-stage burner and CSA and NSF certification. It lists ignition at ultra-low 0.5 GPM and up to 3.9 GPM output for simultaneous use.

It is the pick for boondocking, since the 0.5 GPM startup saves propane and fresh water. It performs at 9,800 feet per the listing.

What works

Ultra-low 0.5 GPM startup
CSA and NSF certified
Multi-stage burner
Rated for 9,800 ft

Watch out for

Needs 12V power

Check price on Amazon

Best Thermostatic Chamber · 2 of 4

Ranein RV Tankless Water Heater

Thermostatic mixing chamber
12.8 inch opening
Multi-function remote

Check price on Amazon

Best for: Data-minded buyers

Our take

A great pick for owners who want data from a remote.

Why it made the shortlist

The Ranein RV Tankless Water Heater (RA65LH) is a CSA 65,000 BTU unit claimed at 3.9 GPM with a thermostatic mixing chamber that balances heat output. It fits a 12.8 by 12.8 inch opening and replaces most Suburban and Atwood 6, 10 and 12 gallon heaters.

A multi-function remote shows gas use, voltage, flow and anti-freeze status, which no other pick lists. Compared with the AVOYTE, it adds that remote.

What works

Remote shows gas, voltage and flow
Thermostatic chamber steadies temperature
Fits 12.8 inch opening
CSA certified

Watch out for

Exterior door sold separately

Check price on Amazon

Best Budget Mixing Tank · 3 of 4

AVOYTE RV Tankless Water Heater

16.9 oz mixing tank
65,000 BTU, 12V
7 safety protections

Check price on Amazon

Best for: Budget mixing tank buyers

Our take

Best for budget buyers who want a real mixing tank.

Why it made the shortlist

The AVOYTE RV Tankless Water Heater has a 16.9 oz built-in mixing tank and a 65,000 BTU burner claimed at up to 3.9 GPM. It is CSA certified with seven safety protections and rated for 9,800 feet.

It costs about $280, well below the CAMPLUX and Ranein, and lists anti-freeze protection. The mixing tank buffers overcooled or overheated flow.

What works

Stated 16.9 oz mixing tank
CSA certified
Rated for 9,800 ft

Watch out for

Less brand history
Needs 12V power

Check price on Amazon

Best Premium Altitude Unit · 4 of 4

FOGATTI InstaShower 9 Pro RV Tankless Water Heater

66,000 BTU, 3.6 GPM
Plus or minus 1 F control
150 PSI relief valve

Check price on Amazon

Best for: Precision-temperature buyers

Our take

Best for buyers who want tight temperature control.

Why it made the shortlist

The FOGATTI InstaShower 9 Pro is a third-generation tankless heater with a built-in mixing tank, 66,000 BTU and up to 3.6 GPM. The listing says it runs at altitudes up to 9,800 feet and holds temperature within plus or minus 1 F.

It includes a 150 PSI pressure relief valve and a 13 by 13 inch opening that can replace Suburban and Atwood heaters.

What works

Plus or minus 1 F temperature control
Relief valve included
Rated for 9,800 ft
13 by 13 inch opening

Watch out for

Needs 12V power

Check price on Amazon

Methodology

How We Built This Shortlist

Each pick was assessed across 4 criteria weighted for real-world use.

Mixing tank

Only listings naming a mixing tank or chamber were included.

Flow claims

GPM claims were treated as listing claims.

Certifications

CSA and NSF wording was read exactly.

Fit

Opening sizes were compared.

Decision guide

Match an RV Tankless Water Heater With Mixing Tank to Your RV

By what you want most

Your situation	Recommended pick	Why
Low-flow boondocking	CAMPLUX Elite10	0.5 GPM startup
Remote data	Ranein RA65LH	Multi-function remote
Lowest cost	AVOYTE 65,000	16.9 oz mixing tank at about $280
Tight temperature control	FOGATTI InstaShower 9 Pro	Plus or minus 1 F

By Budget

Budget	Recommended pick
$270 to $450	AVOYTE 65,000 or Ranein RA65LH
$450 to $700	CAMPLUX Elite10 or FOGATTI InstaShower 9 Pro

Mixing tank vs thermostatic chamber

Mixing tank

The CAMPLUX Elite10, AVOYTE 65,000 and FOGATTI InstaShower 9 Pro list a built-in tank that buffers flow.

Thermostatic chamber

The Ranein RA65LH uses a chamber that balances heat output dynamically.

Most buyers should choose the AVOYTE 65,000 for a low-cost mixing tank.

By altitude and climate

Condition	Recommended pick
High altitude	FOGATTI InstaShower 9 Pro
Cold nights	AVOYTE 65,000
Boondocking	CAMPLUX Elite10
Standard cutouts	Ranein RA65LH

For Showers With Kids Specifically

Look for

steady temperature and safeties

In this comparison

The AVOYTE 65,000 lists seven protections and the FOGATTI InstaShower 9 Pro holds plus or minus 1 F.

When to Spend More

Spend more if

Spend more if temperature steadiness matters: the FOGATTI InstaShower 9 Pro and Ranein RA65LH cost more.

Save if

Save if you want the buffer at a low cost: the AVOYTE 65,000 is about $280.

FAQ

Before You Bring One Home

Do I need a mixing tank?

It helps smooth temperature swings, especially at low flow. Without it, some tankless units fluctuate.

What mistake do people make?

Assuming all tankless heaters buffer temperature. Check for a mixing tank or chamber.

Is the Ranein RA65LH worth it over AVOYTE 65,000?

If you want a data remote, yes. Otherwise the AVOYTE 65,000 costs less.

How do I install it?

Shut off propane and power, remove the old unit, connect the water and gas lines and test every joint for leaks. Follow the manufacturer's instructions, and consider a professional for gas work.

How do I winterize it?

Use the freeze protection if the unit is powered and has propane available. Drain the unit and water lines before storing in freezing weather.

Bottom line

The short version

Best Low-Flow Startup
CAMPLUX RV Tankless Water Heater
Check price for CAMPLUX RV Tankless Water Heater (opens in a new tab)
Best Thermostatic Chamber
Ranein RV Tankless Water Heater
Check price for Ranein RV Tankless Water Heater (opens in a new tab)
Best Budget Mixing Tank
AVOYTE RV Tankless Water Heater
Check price for AVOYTE RV Tankless Water Heater (opens in a new tab)
Best Premium Altitude Unit
FOGATTI InstaShower 9 Pro RV Tankless Water Heater
Check price for FOGATTI InstaShower 9 Pro RV Tankless Water Heater (opens in a new tab)

Browse more rv tankless water heater with mixing tank on Amazon →

About the author

Bowen Higgins

RV Editor at RV Gear Lab

Bowen covers RV power, water systems, towing and leveling, upkeep and interior comfort, with a focus on matching gear to the rig, the hookups and the way you actually travel.

4 Best RV Tankless Water Heater With Mixing Tank in 2026: A Practical RV Guide

Our top picks

The Rig Fit Check

What Matters Before You Choose an RV Tankless Water Heater With Mixing Tank

Why a mixing tank

Mixing tank vs chamber

Low-flow startup

Certifications

Opening size

Why You Can Trust RV Gear Lab

The 4 best rv tankless water heater with mixing tank, explained

CAMPLUX RV Tankless Water Heater

Ranein RV Tankless Water Heater

AVOYTE RV Tankless Water Heater

FOGATTI InstaShower 9 Pro RV Tankless Water Heater

How We Built This Shortlist

Mixing tank

Flow claims

Certifications

Fit

Match an RV Tankless Water Heater With Mixing Tank to Your RV

By what you want most

By Budget

Mixing tank vs thermostatic chamber

By altitude and climate

For Showers With Kids Specifically

When to Spend More

Before You Bring One Home

Do I need a mixing tank?

What mistake do people make?

Is the Ranein RA65LH worth it over AVOYTE 65,000?

How do I install it?

How do I winterize it?

The short version

Bowen Higgins

Related guides