Reducing Hot Water Use
One of the easiest and most practical ways to cut your water heating costs is to simply reduce the amount of hot water being used. In most cases, this can be done with little or no initial cost and only minor changes in lifestyle. Some common-sense tips for reducing hot water use include:
- Install low-flow showerheads and faucet aerators. These devices regulate water flow and can save substantial amounts of both energy and water. Low-flow showerheads can reduce flow rates from around 5 gpm (gallons per minute) to 2.5 gpm or less, and are easy and inexpensive to install. Hot water use for an average shower can be reduced from around 50 gallons to 25 gallons or less. There are a wide variety of low-flow showerheads available, including the popular pulsating or "massage" type. Some of these showerheads incorporate a valve or pushbutton which allows the user to interrupt the water flow while "soaping up", saving even more.
- Take showers instead of baths. With a low-flow showerhead installed, showering may use only one-third the hot water of a bath.
- Take shorter showers. The amount of water used is directly related to the time spent in the shower.
- Use the lowest temperature wash and rinse settings on clothes washers. An average load of laundry uses about 32 gallons of water. Switching from hot to cold water will not only save the energy used to heat the water, but can also reduce fading and shrinkage of clothes.
- Operate clothes washers and dishwashers only when full. An automatic dishwasher typically uses about 8 to 14 gallons per cycle. Consider using the "light wash" cycle for lightly soiled dishes - it can save about 3 gallons per cycle. For smaller loads of laundry, use the lowest available water level setting.
- Fix any leaks in pipes or faucets. A leaky faucet can waste 3,000 gallons or more every year. If the leak is in a hot water pipe or faucet, the energy savings could easily pay for fixing the leak.
- Don't leave hot water running while washing or shaving - this wastes both energy and water.
Reducing water use in general can also result in lower water and sewer costs, and can extend the life of plumbing equipment. Operating clothes washers and dishwashers only when full will also extend the life of these appliances, because they will ultimately be used fewer times.
Examples of Savings
If you heat your water with natural gas, it takes an average of about .83 therms of gas to heat 100 gallons of water 60E° F. (the typical difference between incoming water temperature and water heater setting). That leaky faucet, wasting 3,000 gallons a year, may only cost a few dollars to repair, but if the leaking water is hot it can cost you as much as $15 a year in fuel costs (assuming a fuel cost of $.60/therm).
If your water is heated electrically, it takes about 15 kWh to heat 100 gallons of water 60E° F. If you wash two loads of clothes per week, and can switch from hot to cold water, you could save as much as $40 or more per year (assuming a cost of $.08/kWh).
Reducing Hot Water Temperature
If your water heater thermostat is set too high, you may be able to reduce the temperature and prevent energy and money from going down the drain. Reducing the temperature saves energy mainly by cutting down on the amount of heat that is lost through the walls of the hot water tank (known as "stand-by" losses). If appliances such as clothes washers and dishwashers use hot water at the temperature supplied by the water heater, and do not mix this water with cold water to achieve a set hot water temperature, additional savings will occur.
Check the temperature setting of your hot water tank by using a thermometer at a faucet near the tank (thermostat settings on water heaters are not always accurate). Set the thermometer in a glass and run the hot water into the glass until the temperature stops rising.
Consider the following guidelines for common activities using hot water.
Hand washing: 110E° - 115E° F
Showers: 110E° - 115E° F
Dishwashers: Residential-type dishwashers may require 130E° to 140E° F water to perform properly. Some models have built-in booster heaters that allow the water heater to be set at 110E° to 115E° F. Liquid soaps for automatic dishwashers are designed to work well at lower temperatures. Experiment with the water temperature at the dishwasher and choose the most economical setting.
Laundry: Most clothes can be effectively cleaned in either warm or cold water. In fact, hotter water can cause some stains to "set." Washing clothes in warm or cold water will not only save energy, but also prevent premature wear and fading of fabrics. Use a cold water rinse for all loads.
Adjusting The Temperature
Adjusting the hot water temperature is usually straightforward. A plumbing or mechanical contractor can make the adjustment, or you can do it yourself. With an electric water heater, the thermostat is usually located behind a cover plate on the side of the tank, and can be accessed by removing a few screws (many electric water heaters have two thermostats - one for the upper heating element and one for the lower. - be sure to adjust both.).
Caution! When turning down the setting on an electric water heater, be sure to shut off the power at the circuit breaker before removing the control cover plates to avoid the danger of electric shock.
You may find that your first adjustment results in inadequate hot water for your needs. Experiment with the setting to find a temperature that provides adequate hot water, while still minimizing wasted energy.