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Make your hot water heater more efficient

Wed, 12/26/2007 - 1:02am — efadmin

After household heating and cooling, water heating is the largest energy user in your home, representing over 13% of your annual energy bill, and a significant contributor to household CO2 emissions. "If your water heater is more than 10 years old it is likely running at less than 50 percent efficiency—wasting energy and money—but most people don’t replace their water heater until it fails. Upgrading to a new, more efficient model will lower not only your monthly expenses, but also your contribution to air pollution and global warming." Even if you don’t plan on buying a new water heater in the near future, there are a number of measures you can take now to save money, and energy, with your existing system.

The biggest savings can be achieved by simply using less hot water. Not only does it save you money while reducing your CO2 footprint, cutting down on water conserves our water supplies. "A family of four each showering five minutes a day can use about 700 gallons per week—a three-year drinking water supply for one person! Water-conserving showerheads and faucet aerators can cut hot water use in half. That family of four can save 14,000 gallons of water a year and the energy required to heat it."

If your water heater was installed before 2004, consider installing an insulating jacket on your existing water heater. Insulation jackets are inexpensive and easy to install, and are particularly effective if your water heater is located in an unheated space such as a basement. "The insulating jacket will reduce standby heat loss—heat lost through the walls of the tank—by 25–40%, saving 4–9% on your water heating bills." Many newer water heaters already come well insulated, making it unnecessary to install an insulating jacket in terms of any additional economic benefit. In fact, some manufacturers recommend against installing insulating jackets on their energy-efficient models. Always follow the manufacturer’s recommendations, and be careful not to restrict air inlets when insulating conventional gas or oil-fired water heaters.

Insulating your hot water pipes will also reduce heat loss and save you money. Not only does it reduce losses as hot water flows from your water heater to your faucet, insulating your hot water pipes also reduces standby losses when the tap is turned off and then back on in within an hour or so. "A great deal of energy and water is wasted waiting for the hot water to reach the tap. Even when pipes are insulated, the water in the pipes will eventually cool, but it stays warmer much longer than it would if the pipes weren’t insulated."

Turn down the thermostat on your hot water heater. A lot of energy, and money, is wasted simply by setting your thermostat too high on your water heater. "For most households, 120°F water is fine (about midway between the 'low' and 'medium' setting). Each 10°F reduction in water temperature will generally save 3–5% on your water heating costs. When you are going away on vacation, you can turn the thermostat down to the lowest possible setting, or turn the water heater off altogether for additional savings. With a gas water heater, make sure you know how to relight the pilot if you’re going to turn it off while away."

If you are in the market for a new hot water heater, there are several energy-efficient models that you can choose from to meet your needs and budget. They include:

  • Storage water heaters – the most common type on the market. They maintain a large tank of water at a set temperature, and are best suited for larger households that use a lot of hot water. "Storage water heaters have become more efficient over the years, but some energy is still wasted when the hot water is not being used (known as standby energy loss)."
  • Tankless water heaters – also known as on-demand or instantaneous heaters. They use energy only when hot water is needed, resulting in less standby energy loss than storage heaters. "They tend to have a higher up-front cost, but are less expensive to operate in the long term due to their higher efficiency." "Researchers have found savings can be as much as 34% compared with a standard electric storage tank water heater."
  • Solar water heaters – they transfer heat from the sun into a conventional storage tank. "They have higher up-front costs than conventional water heaters but much lower operating costs, and can pay for themselves within 4 to 10 years under favorable conditions." Heating with the sun has the added advantage of helping to reduce your carbon dioxide footprint. "Solar water heaters avoid the harmful greenhouse gas emissions associated with electricity production. During a 20-year period, one solar water heater can avoid over 50 tons of carbon dioxide emissions."

Other tips for conserving energy include:

  • Repairing leaky faucets promptly;
  • Taking showers instead of baths - bathing uses the most hot water in the average household – a typical bath uses 15-25 gallons of hot water, while a 5-minute shower uses less than 10 gallons;
  • Installing heat traps on the hot and cold pipes at the water heater to prevent heat loss – heat traps are essentially one-way valves that prevent unwanted hot water from flowing out of the tank and water that may be sitting in the pipes from flowing back into the water heater; and
  • Draining some water (about a quart) from your water tank several times a year to remove sediment that can impede heat transfer and lower the efficiency of your heater.

References:
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