RV dealers and manuals universally recommend turning off your water heater when not in use to “save energy and extend its life.” The shocking truth? This advice causes more water heater failures than anything else. Industry repair data shows that water heaters switched on/off frequently fail within 18 months, while those left on continuously often last 8-10 years.
Here’s the science dealers don’t understand: thermal cycling is the killer. Every time you heat and cool the tank, metal expands and contracts, creating microscopic stress fractures. The heating elements suffer the worst damageβconstantly expanding and shrinking until they crack. I’ve seen $800 Atwood water heaters destroyed in under a year by well-meaning owners who religiously turned them off “to save money.”
The energy savings myth is equally bogus. A modern RV water heater uses just $15-25 per month when left on continuously with good insulation. But here’s what veterans know:
- Leave it on 24/7 if you’re using the RV more than twice monthly
- Only turn off for storage periods over 30 days
- Install a $40 water heater bypass kit instead of constant on/off switching
- Use the electric element continuously, gas only for quick recovery
One full-timer shared his numbers: three water heaters in four years following dealer advice, costing $2,400 in replacements. Since switching to continuous operation three years ago? Zero failures. The $300 annual electricity cost is nothing compared to replacement and installation fees.