Hot Water with Less Worry
Greentips: October 2010
Warm showers. Sanitized dishes. Hot water is an essential part of our everyday lives, but it comes at a price. Water heaters account for 14 to 25 percent of your home’s energy use (according to the Department of Energy), which has a significant impact on your energy costs and carbon footprint. Upgrading to a more efficient model will save money—and global warming emissions—for years to come.
Conserve Before You Buy
Reducing your water consumption lowers utility costs overall while allowing you to upgrade to a smaller, more efficient water heater. Repairing leaky faucets, installing water-efficient fixtures and appliances, taking shorter showers, washing clothes in cold water, and lowering your water heater temperature (120 degrees Fahrenheit is sufficient for killing germs) are just some of the ways in which you can reduce water heating demands.
Sizing a Heater to Fit Your Needs
A properly sized water heater is critical to maximizing your energy savings. To find the right model for your household, first calculate your “first hour rating” (FHR)—the amount of hot water your family uses during peak times (see the Related Resources for a rating calculator). Then look for water heaters with an FHR within one or two gallons of your needs. Keep in mind that staggering your shower, laundry, and dishwashing schedule could allow you to purchase a lower-capacity model that saves money. In addition, choose a model with a high Energy Factor (EF) rating, a measure of efficiency. FHR and EF numbers are shown on an appliance’s yellow EnergyGuide label.
High-Tech Heating Options
A number of water heaters are on the market that use much less energy to run than conventional tank-style heaters, reducing your environmental impact. While they have higher upfront costs, they can quickly pay for themselves through energy savings. They may also qualify for federal tax credits (see the Related Resources).
- Tankless (on-demand) heaters provide hot water only when it is needed (compared with a conventional tank heater than maintains a supply of hot water 24 hours a day), reducing energy consumption and operating costs by 10 to 20 percent. However, they might not be powerful enough for homes with a high FHR.
- Heat pump water heaters extract heat from the surrounding air (or from underground) to heat water in your existing tank heater, substantially reducing conventional energy consumption. You can also purchase a “hybrid” water heater that combines the tank and heat pump in a single unit. Air-source heaters work best in warm climates.
- Solar heaters work by transferring the sun’s heat (via air or liquid) into a water storage tank. They can be used in any climate, and can cut water-heating costs by 90 percent. Note: Solar heaters do not have EF ratings, but Energy Star-rated models are available.
If you purchase a tank water heater, choose a model with an insulation value of R-16 or higher to prevent heat loss from the tank. And regardless of your system, consider these tips to further reduce wasted energy:
- Insulate hot water pipes to prevent heat loss.
- Wrap your tank heater in an insulating blanket (if it’s not already well-insulated), which can reduce water-heating costs by 4 to 9 percent.
- Turn your unit to the lowest setting (sometimes called “vacation” mode) or shut it off if you will be away for more than three days.
