Rinnai Singapore water heaters are available through Bathroomwarehouse. Rinnai Singapore is a dedicated brand that is committed to providing the best home and living products to its clients. With its products, Rinnai brings innovation, convenience, and practicality into your home. A Rinnai tankless water heater has a life expectancy (or useful lifespan) of up to 20 years. Water quality, usage, and correct upkeep have an impact on actual life.