1. Hot Water Delivery and User Experience

Tank-style heaters store and pre-heat a fixed volume of water, so hot water is available
almost immediately at the faucet. You open the tap, and you’re essentially drawing from a pre-heated reservoir.

Tankless heaters work differently: they need a minimum flow to trigger the burner, then ramp up
to temperature. That means a delay before hot water arrives, and some variability as the system stabilizes.
Certain premium models (like the Truma AquaGo) offer a “comfort” or recirculation mode to keep water warm
in the lines, but that comes with additional energy use.

2. Water Usage and Conservation

One of the big tradeoffs with tankless systems is water waste during warm-up. Until the heater
reaches the target temperature and pushes that hot water all the way to the fixture, you’re sending usable water
down the drain. For anyone with limited gray tank capacity, that’s not trivial.

With a tank heater, the water is already hot and more predictable, so it’s easier to mix hot and
cold at the faucet and get to a comfortable temperature quickly. That can translate into less fiddling and less
waste overall.

3. Fuel, Power, and Flexibility

A common selling point for tankless heaters is efficiency: they only fire when water is flowing.
Many RV owners report lower propane usage after switching to tankless, especially if they take longer showers.

Tank heaters, on the other hand, often support multiple modes—propane, electric, or both.
That flexibility matters at campgrounds where shore power is available: you can save propane by running on
electric, or use both for faster recovery when demand is high.

4. Winter Performance and Cold-Weather Behavior

Cold weather exposes some of the weaknesses of tankless systems. They can be more sensitive to:

• Low incoming water temperatures
• Low water pressure or marginal pumps
• Temperature rise limits across the heat exchanger

Owners in colder climates sometimes add insulation, small heaters, or circulation loops to keep lines from
freezing and to stabilize performance. By contrast, tank heaters tend to be more predictable
in winter, as the entire tank is kept at temperature and the system is generally simpler.

5. Installation, Tuning, and Reliability

Tankless units are more “tunable” but also more finicky. They care about:

• Water pressure: too low and they may not fire consistently.
• Flow rate: fixtures with very low-flow aerators can cause cycling.
• Temperature rise: large jumps from cold inlet to hot outlet push the unit harder.

Tank heaters are mechanically simpler and often more forgiving. While both types can be reliable
when installed correctly, the tank-style design has fewer variables to tune and fewer edge cases to manage.

6. Real-World Experiences from RV Owners

The comments and user experiences around this topic are split, but informative:

• Pro-tankless: Full-timers love the “endless shower” experience and reduced propane usage.
• Back-to-tank: Some owners reverted to tank heaters after frustration with cold-weather
  performance or water waste.
• Hybrid setups: Others run creative combinations—small under-sink electric heaters,
  recirculation loops, or dual-mode tank heaters—to get the best of both worlds.

How This Informs My Trailer Build

For my cargo trailer conversion, the decision isn’t just “tank vs. tankless”—it’s about how the entire
hot water system interacts with gray tank capacity, winter use, and
fixture layout.

• Endless hot water is appealing, but the delay and extra water down the drain are real
  concerns with a finite gray tank.
• Cold-weather reliability matters, especially if the trailer sees shoulder-season or
  winter trips.
• A hybrid approach—for example, a traditional tank heater combined with a small
  point-of-use electric heater near the shower or sink—could minimize wait time and water waste.
• Heater placement relative to fixtures will be critical. Shorter runs mean less delay,
  less wasted water, and a better overall experience regardless of heater type.

I’m leaning toward a solution that prioritizes predictability, water conservation, and serviceability,
even if that means giving up the “infinite” hot water promise of a pure tankless setup.