Water heater
When installing a power-vented boiler in a home, don’t miss the opportunity to upgrade the homeowner to a high-efficiency water heater at the same time. Photo credit: ©istockphoto.com/pastorscott

If anyone needed a reminder, Hurricane Sandy showed just how important plumbing and heating contractors are to disaster recovery. With winter around the corner and hundreds of thousands of homes damaged or destroyed, contractors scrambled for months to keep up with the demand for replacement equipment in flood-soaked basements.

In New Jersey, the rapid replacement of so many furnaces and boilers drew attention to another common household hazard: The carbon monoxide risk posed by “orphaned water heaters” when an old furnace or boiler is replaced by a high-efficiency power-vented one. Recognizing the danger, the state’s Clean Energy Program took action by offering contractor training, consumer education and cash rebates for simultaneous replacement of space- and water-heating equipment.

This lesson extends far beyond the flood-damaged homes of the Northeast. When a power-vented boiler or furnace is being installed, don’t miss the opportunity to upgrade to a high-efficiency water heater at the same time.


Problem and opportunity

The orphan water heater concern actually stems from a positive development in home heating. Spurred by consumer demand and federal standards, high-efficiency gas furnaces and boilers are increasingly popular nationwide, making up a majority of heating system installations in many northern states. This equipment is normally power-vented using a fan to help flue gases exhaust or direct-vented with plastic piping through the side of the house, leaving the existing flue unused except for the newly orphaned water heater.

Without the boiler or furnace to help warm up the flue and maintain the stack effect, the exhaust from the legacy water heater may not be hot enough to adequately vent combustion gases to the outside. The result is harmful gases escaping into the living quarters.

Because carbon monoxide is both deadly and impossible to detect, combustion appliances need to vent 100% of the time. Other household vented applications (bathroom fans, fireplaces, etc.) only make it more difficult for orphaned water heaters to adequately vent through oversized flue pipe and chimneys.

A common solution for orphaned water heaters is to install a chimney liner. A correctly sized chimney liner can make modest draft improvements. Depending on code and installation requirements, this may suffice, but a better solution is to lessen the risk of insufficient draft: a power-vented or direct-vented high-efficiency water heater.

Energy Star water heaters excel at energy savings and reliability, and model configurations include gas storage, gas tankless, electric heat pump and solar water heaters. Many of these systems rely on power or direct venting, although traditional atmospheric venting models also are available.

These models provide significant energy savings throughout the life of the water heater. Since heating water is the second-largest energy use in homes (after space conditioning), those savings add up quickly over the life of the unit.


Avoiding an emergency replacement

In addition to improving safety and saving money, another reason for homeowners to replace their water heaters when upgrading the heating system is convenience. Just as contractors dread callbacks to past jobsites, customers want disruptive home improvements completed efficiently and conveniently at one time. When each contractor visit means a day of missed work, homeowners appreciate combining multiple projects and the confidence of having new space- and water-heating systems.

Homeowners usually don’t think about replacing their water heaters until they wake up on a cold morning and stumble to the shower only to find they have no hot water. By then, customers are limited to choosing a new model from whatever the contractor has on hand. Beyond the unpleasant cold shower, this costs customers in the long run if they are stuck with an inefficient water heater and higher energy costs for years to come.

The average lifespan of a home water heater is between 10 and 15 years, but this varies depending on use, water quality and maintenance. These signs can indicate a water heater is on the brink of failure:

  • Rusty water. Hot water that turns reddish or leaves rust streaks in the bathroom is a sign the water heater needs to be replaced soon, especially if the unit is nearing the end of its useful life. If the water heater is only a couple of years old, a replacement anode rod and tank flushing may suffice.
  • Leaking. Look for water pooled around water connections above the tank, as well as under and around the water heater. When the unit is leaking, it is nearing its final days. A pinhole leak will grow quickly.
  • Less hot water. When it takes longer for water to heat up, mineral scale and sediment can be building up inside the tank.
  • Boiling noises. Bubbling and boiling sounds in the tank while the water heater is firing can be another sign of mineral scale and sediment buildup.

Mineral scale and sediment can build up over years of use on the inside walls and bottom of the water heater. This buildup interferes with heating the water, so the unit uses more energy and takes longer to heat the same amount of water. It also may shorten the life of the water heater. Sediment buildup can be reduced by regular flushing, although severe buildup may require complete replacement.

Many local utility companies and some states provide rebates and incentives for choosing high-efficiency models, such as Energy Star-certified models (http://www.eswaterheaters.org). New Jersey’s efforts after Hurricane Sandy included a large rebate, consumer education and contractor training about simultaneous replacement of space-heating and water-heating equipment.

Regardless of local climate or building construction, a new heating system always calls for an examination of other equipment affected by the change. Upgrading a water heater to a high-efficiency, power-vented or direct-vented model is one important way to prevent orphaned water heaters while helping homeowners save money.


About the author: Philip Picotte is a program associate with the Consortium for Energy Efficiency.