Hot Water System Options
The hot water system supplies the bathroom and kitchen with heated water for daily use.
This page outlines the available heater types, their advantages, installation considerations, and how each option integrates with the overall plumbing layout.
The garage is the leading candidate for installation due to its ventilation, service access, and proximity to the bathroom.
1. System Requirements
The hot water system must supply heated water to the following fixtures:
- Bathroom sink
- Shower
- Washer/Dryer Combo (if supported)
- Kitchen sink
PEX hot water lines will run from the heater location (likely the garage) upward into the bathroom and forward to the kitchen.
2. Tankless Propane Water Heater
A tankless propane heater is one of the most common solutions for RV and trailer builds.
It provides unlimited hot water as long as propane and water flow are available.
Pros
- Unlimited hot water
- Fast recovery time
- Compact footprint
- Low electrical draw (mostly for ignition and controls)
- Ideal for garage installation with proper venting
Cons
- Requires propane supply and regulator
- Needs exterior venting
- Minimum flow rate required to activate burner
Best For
Full‑time or frequent use, long showers, and multi‑fixture hot water demand.
3. Electric Tankless Water Heater
Electric tankless heaters provide on‑demand hot water without propane, but they require significant electrical capacity.
Pros
- No propane required
- Compact and simple installation
- No combustion gases or venting
Cons
- Very high electrical demand (often 40–60 amps)
- Not ideal for off‑grid or limited‑power setups
- May require electrical upgrades
Best For
Shore‑power use or locations with strong electrical service.
4. Small Electric Tank Water Heater (4–6 Gallons)
A compact electric tank heater stores a small amount of hot water and reheats as needed.
This is a simple and reliable option for moderate hot water use.
Pros
- Low electrical draw compared to tankless
- Stable water temperature
- Easy installation
- No propane or venting required
Cons
- Limited hot water capacity
- Recovery time required between uses
- Not ideal for long showers
Best For
Light to moderate hot water use, shore‑power environments, and simple installations.
5. Marine/Hybrid 12V + 120V Water Heater
Marine water heaters can run on 120V AC or engine coolant loops.
In a trailer build, only the electric mode is used, but they offer excellent insulation and recovery.
Pros
- Highly insulated and efficient
- Dual‑power capability (12V assist on some models)
- Reliable and long‑lasting
Cons
- More expensive than RV heaters
- Larger footprint
- Not tankless — limited capacity
Best For
Users who want a premium, efficient, long‑life hot water solution.
6. Recommended Installation Location: Garage
The garage is the preferred location for the hot water heater due to:
- Ventilation (especially for propane tankless)
- Service access from both inside and outside
- Proximity to bathroom fixtures
- Space for mounting and routing PEX lines
- Ability to isolate heat and noise from living areas
PEX lines will run upward into the bathroom and forward to the kitchen, creating a clean and centralized plumbing layout.
7. Hot Water Routing Plan
Regardless of heater type, the hot water distribution will follow this path:
- Heater (garage)
- Bathroom sink
- Shower
- Washer/Dryer Combo
- Kitchen sink
This routing minimizes pipe length and ensures fast hot water delivery to the bathroom, which is the highest‑use zone.
8. System Summary
The hot water system is a critical part of the trailer’s plumbing design.
Tankless propane heaters offer unlimited hot water and are ideal for garage installation,
while electric tank or hybrid heaters provide simpler, low‑maintenance alternatives.
All options integrate cleanly with the bathroom‑centered plumbing layout and supply both the bathroom and kitchen.
As the build progresses, this page will be updated with the final heater selection, mounting details, and installation notes.