Best RV Tankless Water Heaters
Endless hot water in a six-gallon bay, if your pump can hold the pressure.
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The Girard GSWH-2 is the standard RV tankless retrofit: 42,000 BTU/h, 0.9 to 1.5 GPM, a digital panel setting output between 95 and 124°F, and under 3 A at 12 V DC. It needs 45 to 125 psi of water pressure, which is the specification to check against your pump before anything else.
Converting an RV from a 6-gallon tank to tankless is one of the most satisfying upgrades in the category, because the complaint it fixes — a four-minute shower — is so specific. It is also the upgrade most likely to disappoint, for one reason: water pressure.
Check the pump before you buy the heater
The Girard GSWH-2's published range is 45 to 125 psi at 0.9 to 1.5 GPM. Many factory-fitted RV pumps are specified around 45 psi at best and deliver less in practice, particularly when the fresh tank is low or the filter is partly blocked.
Below the minimum the unit cycles on and off, or will not fire at all, and the symptom is exactly what you were trying to escape: cold water mid-shower. The fix is a better pump with an accumulator. If you are budgeting for a tankless conversion, budget for both.
Quick picks
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| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  Girard GSWH-2 RV tanklessThe standard tankless retrofit for a 6-gallon RV bay: 42,000 BTU/h, 0.9 to 1.5 GPM, and a digital panel that sets the output temperature between 95 and 124°F instead of making you mix at the faucet. | Replacing a 6-gallon RV tank | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 2 |  Camplux Pro 10 (2.64 GPM propane)A 2.64 GPM propane unit that runs off a BBQ cylinder — the right answer for a cabin shower or an outdoor wash station, and the wrong answer for a house. | Outdoor and off-grid propane | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 3 | Camplux 10L Pro BD264 portableThe bigger portable: 2.64 GPM and 68,000 BTU/h with an LED set-point display, which is enough flow for an actual shower rather than a rinse. | A real shower off-grid | Check price on Amazon No live price feed on this site, so we show none. #ad |
The picks in full
Pick 1 — Replacing a 6-gallon RV tank
Girard GSWH-2 RV tankless
The standard tankless retrofit for a 6-gallon RV bay: 42,000 BTU/h, 0.9 to 1.5 GPM, and a digital panel that sets the output temperature between 95 and 124°F instead of making you mix at the faucet.
| Fuel | Propane |
|---|---|
| Gas input | 42,000 BTU/h |
| Flow | 0.9 - 1.5 GPM |
| Water pressure | 45 - 125 psi |
| Electrical | 12 V DC, under 3 A |
| Control | Digital wall panel, 95 - 124°F |
What is good
- Endless hot water in a bay that previously held six gallons
- Under 3 A at 12 V, so it runs on house batteries
- Set-point control means a consistent shower instead of chasing the mixer
- Drops into the common 6-gallon opening
What is not
- Needs 45 psi, which an undersized RV pump may not deliver
- Tankless means no reservoir, so a dropped-out pump equals instant cold
- Requires winterizing like any tankless unit
Skip it if: Skip it if you dry camp with a low-output water pump. Below the 45 psi minimum the unit will cycle or refuse to fire, and the fix is a new pump — budget for both or stay with a tank.
No live price feed on this site, so we show none. #ad
Specifications above from Campervan HQ listing, Girard GSWH-2. We have not tested this unit ourselves.
Pick 2 — Outdoor and off-grid propane
Camplux Pro 10 (2.64 GPM propane)
A 2.64 GPM propane unit that runs off a BBQ cylinder — the right answer for a cabin shower or an outdoor wash station, and the wrong answer for a house.
| Fuel | Propane (20 lb cylinder) |
|---|---|
| Output | 2.64 GPM |
| Gas input | 65,000 - 68,000 BTU/h depending on model variant |
| Temperature rise | Rated flow quoted at a 70°F rise |
| Temperature range | 50 - 140°F, adjustable |
| Minimum activation flow | 0.5 GPM |
| Installation | Outdoor / vented enclosure only |
What is good
- 0.5 GPM activation is low enough for an RV pump or a gravity-fed line
- Runs on a standard 20 lb propane cylinder with no gas line or permit
- 2.64 GPM is a genuine shower, not a trickle
- Temperature is set on a dial rather than by mixing at the fixture
What is not
- Outdoor use only — these are not indoor-rated appliances
- Battery or 12 V ignition means it stops working when the batteries die
- No freeze protection: it has to be drained for winter
Skip it if: Skip it for anything inside a house. These units are certified for outdoor use and venting an outdoor-rated propane heater indoors is a carbon monoxide risk, not a code technicality.
No live price feed on this site, so we show none. #ad
Specifications above from Tractor Supply listing, Camplux 2.64 GPM 68,000 BTU; Lowe's listing, Camplux Plus 10, 2.64 GPM 65,000 BTU. We have not tested this unit ourselves.
Pick 3 — A real shower off-grid
Camplux 10L Pro BD264 portable
The bigger portable: 2.64 GPM and 68,000 BTU/h with an LED set-point display, which is enough flow for an actual shower rather than a rinse.
| Fuel | Propane |
|---|---|
| Output | 2.64 GPM |
| Gas input | 68,000 BTU/h |
| Temperature range | 50 - 140°F, adjustable |
| Display | LED set point |
| Cylinder runtime | About 16 hours of continuous use on a 20 lb cylinder |
| Certification | CSA approved |
What is good
- 2.64 GPM is twice the 5 L unit's flow — the difference between a rinse and a shower
- LED display makes the set point readable in daylight
- Around 16 hours of continuous running on one 20 lb cylinder
- Same six-way protection suite as the smaller Camplux units
What is not
- Needs more water pressure than the 5 L model to reach rated flow
- Heavier and bulkier to carry
- Outdoor use only, and it has to be drained before a freeze
Skip it if: Skip it if your only water source is a gravity jug. The higher flow rating assumes real supply pressure; with a trickle feed you will get the 5 L unit's performance from a bigger, heavier box.
No live price feed on this site, so we show none. #ad
Specifications above from Tractor Supply listing, Camplux Pro 10 L BD264. We have not tested this unit ourselves.
Installed, or portable?
| Installed (Girard GSWH-2) | Portable (Camplux) | |
|---|---|---|
| Fits | The existing 6-gallon bay opening | Hangs outside, stores inside |
| Output | 0.9 to 1.5 GPM | 1.32 GPM (5 L) to 2.64 GPM (10 L) |
| Gas input | 42,000 BTU/h | 34,000 to 68,000 BTU/h |
| Power | 12 V DC, under 3 A | 2 x D batteries, or 12 V on some models |
| Serves the interior bathroom? | Yes | No — outdoor use only |
| Minimum pressure | 45 psi | 3 psi on the 5 L model |
| Winterizing | Required, per manufacturer procedure | Just drain it |
The 12 volt dependency
Every RV tankless unit needs 12 V power for its controls, ignition and flow sensing. The Girard draws under 3 A, which is modest but not nothing over a week of dry camping.
What that means practically: a dead house battery means no hot water, even with a full propane tank. A 6-gallon tank with a working pilot does not have that failure mode. If you dry camp hard and your battery bank is marginal, that is a point in the tank's favor that nobody mentions.
Winterizing a tankless RV unit
More demanding than a tank, because there is very little water in the unit and a lot of narrow passages. A split heat exchanger is not a repair, it is a replacement.
- Follow the manufacturer's drain-down procedure precisely — do not improvise from a tank procedure.
- Open every drain point the manual identifies, not just the obvious one.
- Use compressed air at the pressure the manual specifies, if it specifies one.
- Where the manufacturer permits antifreeze through the unit, use the RV type, never automotive.
- If you store somewhere that freezes and are unsure, have it done once by someone who knows the unit and watch.
What goes in with it
A water heater is a system, not a box. These are the parts that go in with it, and the ones people discover they need halfway through the job.
- RV anode rod
Suburban and Mor-Flo tanks need one. Atwood aluminum tanks do not, and fitting one does damage.
- Descaler
RV tanks and tankless units scale faster than house units because of the water you fill from.
How we chose
Published pressure and flow requirements first, because that is what determines whether the unit works in your coach; then gas input and temperature control; then electrical draw. We have not tested these units. How we pick.