RV Tankless Water Heater Benefits and Drawbacks
Quick answer: the main benefit of a tankless water heater for an RV is continuous hot water while you have enough fresh water and fuel. It can also avoid repeatedly reheating a stored tank. The drawbacks are minimum flow requirements, installation constraints, winterisation and the need to match the heater to the RV’s gas, electrical and ventilation systems.
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A tankless unit can be a worthwhile upgrade for people who take longer showers, travel as a family or dislike waiting for a small storage tank to recover. It is not automatically the best choice for every motorhome, camper or travel trailer. Your water supply, power source, touring climate and existing cut-out matter more than the word “tankless”.
How an RV tankless water heater works
A flow sensor detects when you open a hot tap. The heater then starts its burner or electric heating elements and warms water as it passes through. When the tap closes, heating stops. Unlike a conventional six- or ten-gallon RV heater, there is no stored tank of hot water waiting to be used.
Most purpose-built RV models use propane for the main heat source and 12-volt power for controls, ignition and the display. All-electric tankless heaters can demand substantial mains power, so check the current draw rather than assuming a leisure battery and inverter can run one.
Seven benefits of a tankless water heater for an RV
1. Continuous hot water
There is no fixed tank to empty. Hot water continues as long as the unit can maintain the selected temperature and the RV has water, fuel and electrical control power.
2. No tank recovery wait
A storage heater needs time to reheat after its hot water is used. A correctly sized tankless heater responds to flow instead, which can make back-to-back showers more convenient.
3. Heating only when needed
The heater does not need to keep a tank hot between uses. Real fuel savings depend on usage, standby habits, incoming water temperature and the efficiency of the old and new systems.
4. Stable outlet temperature
Modern RV-specific units can modulate the burner to target a set temperature. Performance still depends on adequate water flow, propane pressure and correct installation.
5. Potential space and weight benefits
Some replacements remove the weight of a stored tankful of water. The heater, door assembly and adapters still add weight, so compare complete installed figures.
6. Convenient controls
Many units provide a digital temperature control and fault codes. This can be more convenient than mixing very hot stored water with cold water at the tap.
7. Useful for families and full-time travel
Higher hot-water demand is where continuous heating is easiest to appreciate—provided the fresh-water and waste tanks can support that use.
Drawbacks to understand before buying
- Minimum flow: some heaters will not ignite below a stated flow rate.
- Water use: “endless” hot water can fill the grey tank quickly when camping off-grid.
- Temperature rise: very cold incoming water may reduce achievable flow.
- Installation: cut-out size, gas line, flue, door and plumbing may need adaptation.
- Winterisation: residual water can freeze and damage the heat exchanger.
- Power: controls need reliable 12-volt power; electric heating needs much more.
- Maintenance: scale and restricted flow can affect performance.
Propane versus electric tankless heaters
Propane is usually the practical choice for off-grid RV use because it delivers high heat without a large mains electrical supply. An electric tankless heater may suit a vehicle used almost entirely on a sufficiently rated hook-up, but the circuit requirement must be checked carefully. A small inverter is not a substitute for the required supply.
Retrofit checklist
- Measure the existing opening and exterior door.
- Confirm the unit is approved for RV use and mobile installation.
- Check propane type, pressure, regulator and line capacity.
- Check 12-volt control requirements or mains circuit demand.
- Confirm hot- and cold-water connection positions.
- Review required water flow and temperature rise.
- Plan drainage, pressure relief and winterisation access.
- Check warranty conditions and professional-installation requirements.
Is an RV tankless water heater worth it?
It is most compelling for families, full-time travellers and owners who regularly use onboard showers. A conventional tank may remain simpler for occasional touring, low water use or cold-weather storage. Compare the complete installed cost and compatibility, not just the heater price.
For product types and buying checks, read our best RV tankless water heaters guide. You can also review the broader RV water systems guide and fresh-water tank cleaning checklist.
Compare RV tankless water heaters on Amazon.
Frequently asked questions
Does a tankless RV water heater use less propane?
It avoids holding a tank at temperature, but total fuel use depends on water temperature, flow and shower length. Longer showers can offset standby savings.
Can an RV tankless heater run on battery power?
Propane models often use 12-volt power for controls and ignition, not as the main heat source. An electric tankless heater may require far more power than a typical battery system can provide.
Can I replace any RV water heater with a tankless model?
No. The opening, door, flue, fuel, wiring, plumbing and approvals must all be compatible. Use the manufacturer’s retrofit instructions or a competent RV technician.
Last updated: July 2026.