Get endless on-demand hot water, space savings, eco-efficiency and peace of mind from the world’s most reliable tankless gas water heater brand.  Whether you need a residential water heater or commercial water heater, a Rinnai® tankless water heater will meet your needs. It’s time to expect more because you deserve it.  In addition to the endless hot water, all Rinnai tankless water heater models support natural gas or propane fuel types, as well as flexible installation options for either indoor or outdoors. From there, you can pick a water heater with features that fit your exact needs.