If You’re going off grid a generator can be used to heat water in an RV, but there are some important details to consider:
✅ How It Works
Most RVs heat water using one or more of these systems:
- Propane-powered water heater
- 120V electric water heater element
- Tankless (on-demand) water heater – often propane-based but may use electricity
- Hydronic systems (rare in small RVs)
If your RV has an electric water heater or electric mode, a generator can power it if:
- The generator provides enough wattage (usually 1,200–1,800 watts for water heaters).
- You have the appropriate outlet and connection (e.g., 30A or 50A plug).
- The generator is running steadily while the heater is on.
🔌 Typical Power Needs
| Water Heater Type | Power Draw |
|---|---|
| 6-gallon electric element | ~1,440 watts |
| 10-gallon electric element | ~1,500–1,800 watts |
| Tankless electric heater | 12,000–18,000 watts (not RV-suitable) |
A portable generator of 2,000–3,000 watts is usually sufficient for electric water heating if nothing else high-powered is running (like an AC unit).
🛠️ Practical Tips
- Turn off other appliances (microwave, A/C) while heating water.
- Use propane mode if conserving generator fuel or power.
- Monitor generator load to avoid tripping breakers.
❌ Not Recommended:
- Using electric tankless water heaters in an RV – they draw too much power for typical RV generators.
- Using a small generator (<2000W) to run both water heat and other heavy devices at once.
🔋 Alternative Options
- Use propane-only mode to save generator fuel.
- Shore power is more efficient if available.
- Solar with inverter may support small water heaters if well-designed, but usually not practical for long heating.
The time it takes to heat water in an RV water heater using a generator depends on:
- Size of the water heater (gallons)
- Heating method (electric vs. propane)
- Wattage of the electric heating element
- Starting water temperature
🔥 Typical Electric Water Heater (Using Generator)
| Tank Size | Wattage (120V) | Heat Time (Approx.) |
|---|---|---|
| 6 gallons | 1,440 watts | 45–60 minutes |
| 10 gallons | 1,440–1,800 watts | 60–90 minutes |
These times assume:
- A cold water start (around 50–60°F or 10–15°C)
- Heating up to 120–130°F (49–54°C)
- Continuous generator output with no power dips
⛽ Using Propane + Electric (Dual Mode)
Many RV water heaters can run both propane and electric at the same time, which cuts heating time nearly in half.
| 6-gal Dual Mode | ~20–30 minutes
| 10-gal Dual Mode| ~30–45 minutes
⚠️ Generator Notes
- Make sure your generator can handle 1,500–1,800 watts continuously.
- Avoid overloading by turning off other high-draw appliances (A/C, microwave) while heating water.
🧠 Pro Tip
To conserve generator fuel, heat water just before you need it, and use insulation on the tank if you’re storing hot water for hours.