Building Codes Assistance Project

Heating water accounts for approximately 14% to 25% percent of energy use in the typical home. High efficiency water heaters use 10% to 50% less energy than standard models. When combined with complementary products like insulation blankets and timers, advanced systems can save significantly on utility costs. Actual energy savings from high efficiency water heaters depend on several factors such as heater location, family size, use behavior, heating fuel used, climate zone, and the size and placement of water pipes.

Consumers face many considerations when selecting a new water heater for their home. There are several types of high efficiency water heaters -- each with different advantages and payback periods -- including:

• Efficient storage tank heaters
• Demand (tankless) heaters
• Heat pumps
• Tankless coil and indirect heaters
• Solar heaters with electric back-up

After making their purchases, homeowners can achieve further energy savings in fairly simple and inexpensive ways by properly installing and insulating their water heaters, potentially reducing standby heat losses by 25% to 45% and lowering water heating costs by 4%-9%. Options include installing thermal blankets, insulating hot water pipes, and installing a timer that turns the heater off at night when occupants do not use hot water and/or during utilities' peak demand times during the day.

There are many efficient domestic water heaters -- that are not specified by the model codes that can save energy and money as well as reduce peak electricity demand. For more information, visit www.BuildingGreen.com.

In certain climates, energy codes can be strengthened by including certain advanced techniques and products above in residential water heating requirements.

The following section provides examples of these types of code improvement language or methodologies in these areas.

Policy Options

• Revise Restrictions on Electric Resistance Water Heating
  

  • City of Austin (Texas) Energy Code amending 2006 IECC (applicable to hot/humid climates only):
    403.9 Water Heating. Residential Buildings, as defined by Chapter 2 of the 2006 International Energy Conservation Code, having an existing or planned natural (or equivalent district) gas service located within the adjacent right-of-way shall not use electric resistance water heating as the primary source for hot water.
    Residential Buildings, as defined by Chapter 2 of the 2006 International Energy Conservation Code, not having natural gas service located within the adjacent right-of-way may install electric resistance water heaters having a minimum efficiency of 93% in conjunction with a preprogrammed water heater timer in lieu of gas fired water heating. The timer shall be preprogrammed to turn the water heater off between the hours of 3:00PM and 7:00PM from June 1 to September 30 and from 12:00AM to 4:00AM throughout the year. The timer shall have a readily accessible override, as defined by the building official, capable of restoring power to the water heater for one hour when activated.
    In all instances an electric resistance water heater may be used as a secondary heater in series with a primary water heater that is not electric resistance.

• Require high-efficiency and/or direct-vent water heaters





More coming soon!

**Images courtesy of Building Energy Codes Resource Center