tankless water heater installation cost average
1 CostHelper readers report paying $70 -$1,706 for installation, for an average expense of $630. 2  An electric water heater can cost $400-$3,000 or more for complete installation of a conventional storage-tank model and $1,800-$4,500 or more for a tankless model (including a 220V/240V outlet). With all needed parts and labor, hiring a plumber to install a traditional gas water heater costs $300-$3,500 or more, depending on capacity (with 40 or 50 gallons the most common sizes); length of warranty (typically 5-12 years); and the amount of repairs required to meet current building codes.