1 Tankless Water Heaters – Deemed Savings Issues May 7, 2002

2 Savings Depend Upon “Going Completely Tankless” Savings from “tankless” water heater result from the elimination of “standby losses” Tankless water heaters must be provide for “whole-house” hot water needs to eliminate the need for standard storage tank

3 Maximum Potential Average Energy Savings from Tankless Electric Water Heaters If ALL Standby losses are eliminated on a 50 gallon tank located annual savings = –461 kWh/yr (for tanks located outside heated space) –368 kWh/yr (for tanks located inside heated space)* Post-January 2004 savings = –293 kWh/yr (Outside) –229 kWh/yr (Inside) *Weighted for saturation of electric water heating in non-electrically heated homes

4 “Whole-House” & “Point-of-Use” Similar kWh, Different KW Multiple “point-of-use” tankless waters and single “high-capacity” tankless water heaters can produce roughly equivalent savings Multiple “point-of-use” water heaters will produce lower “peak-load” impacts than single “high-capacity water heaters.

5 “Point-of-Use” Tankless Water Heater Capacities Capacity (KW)Maximum 115 F (gpm)

6 Whole-House Tankless Water Heater Capacities Capacity (KW)Maximum 115 F (gpm) Maximum 105 F (gpm)

7 Standard Tank Daily Load Profile

8 “Whole-House” Tankless Water Heater Daily Load Profile To Be Developed