When converting FROM tank heaters TO tankless, installing a tankless water heater in the attic is actually the preferred location and the least expensive install location when comparing to most other locations such as the garage. Ultimately, attic installations are easier because everything is in plain sight. No guesses, no drywall removal, or heavy demolition to be able to access the various existing and reusable components (gas lines, drain lines, etc.). An electrical outlet is easier to locate and extend in the attic, and there is minimal guess work on how we will install the exhaust venting. Another often unrealized benefit of tankless in the attic is that your exposure to catastrophic failure of ruptured tank heaters is significantly reduced. Especially when you add an emergency shutoff device (i.e., Flood Stop) to the new install. In the case of an unexpected failure, a tankless water heater holds less than 3 gallons of “cold” water versus tanks holding 100 gallons of “hot” water above your living areas.