Truma sells three instant water heater models, all in the same size. The water heaters have a water volume capacity of 0.35 gallons and a normal input rate ranging from 20,000 to 60,000 BTUs per hour.
Each model uses propane gas for heating the water. A 12-volt direct current power supply powers all electronics in the heaters.
The basic model has a power switch and provides water on demand. The comfort model features two modes, eco and comfort. The comfort mode keeps water at a constant 102 degrees Fahrenheit. The Comfort Plus model requires specialized plumbing to ensure that water is instantly available at all showers and faucets.