A: Tankless water heater installation in Tampa Downtown runs $3,158 to $4,371 for Rheem (Premium) gas or $3,935 to $5,010 for Navien (Elite) gas, and $1,369 to $2,260 for Rheem electric or $2,107 to $3,075 for Stiebel Eltron (Elite) electric; modifications are quoted in writing. Converting from a tank to tankless may require new gas lines, venting, or electrical work. high-rise concrete, converted warehouse lofts homes from the 1900s to 2020s (mixed high-rise and converted) sometimes need minor plumbing upgrades. We provide free estimates and offer financing to make the upgrade affordable for Tampa Downtown homeowners.