LCEC – Lee County Electric Cooperative

Water Heating

Solar Water Heating

The subtropical sunshine of Southwest Florida offers a plentiful source of free solar energy; however, the equipment needed to capture and store solar energy can be expensive. The typical solar water-heating system consists of collectors, a pump, a storage tank and electric controls. Because solar heat must be captured and stored during daylight hours for use throughout the day, the storage tank should be significantly larger than a typical tank-type water heater. A well-designed solar water-heating system will save up to 80 percent of the cost of heating water. Don’t forget maintenance costs when figuring payback time on a solar water-heating system. Constant exposure to the sun makes solar collectors high-maintenance equipment. It’s not unusual to require repair or replacement of collectors within seven to 10 years.

Water heating can account for 14 to 25 percent of the energy consumed in your home, second to cooling and heating. Understanding your habits, learning how to conserve and installing the most efficient water heater that best fits your needs will help manage your water heating costs.

Because daily baths and showers are the primary use of hot water, family size drastically affects the annual energy use of heating water. A 40-gallon water heater in Florida consumes 150 to 200 kWh per month for a two-member household with standby heat loss when set at 120 degrees Fahrenheit, depending on water-heater efficiency.

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Although other methods of heating water are more energy efficient, they may not be cost-effective. Purchasing expensive water-heating equipment is not recommended unless the projected savings will pay back your initial investment in a reasonable period of time (less than five years).

Tankless Water Heaters

Unlike conventional hot-water tanks, which are activated by a thermostat, tankless water heaters are activated by the flow of water when a hot-water valve is opened. Although this theoretically provides an instant, unlimited supply of hot water, there are several issues to consider.

• They are designed for single-area water heating; therefore, high fluctuations in hot-water temperature may occur when there is a demand for hot water at several different points. This could cause scalding.
• They may require additional electrical work to support the high amperages of the heating elements, as well as special plumbing and space considerations.
• They may not be cost-effective. Cost of each unit may be comparable to a top-of-the-line conventional water heater. However, two or three units may be required to provide enough hot water for all the requirements in a home.
• Those between 12 and 15 kWh consume about 360 to 450 kWh per month for one hour of daily usage, compared to a single tank-type unit that consumes 180 to 290 kWh per month for an hour of daily usage, even with standby heat loss.
• They are promoted nationally to save on standby heat loss, but in Florida, most water heaters are located in hot garages and have very little heat loss. Additionally, the temperature of cold water entering a water heater in Florida is warm for most of the year.

Heat Pump Water Heaters

The latest technology to gain popularity in water heating is the heat pump or hybrid heat pump water heater.

• This electric storage-tank-type heater uses a heat pump to heat the water versus an electric element, using 62% less energy than a standard electric 50-gallon water heater.
• Manufacturers estimate more than $300.00 annual savings in water heating expenses.
• The unit also has a heating element, the same as a standard electric water heater, which can be used in conjunction with the heat pump to provide fast recovery in times of high hot-water demand.
• The byproduct of the heat-pump water heater is cool-air exhaust into the room in which it is installed, which could be an added benefit in southwest Florida.
• The control pad allows the user to select the mode of operation, such as heat-pump-only mode, hybrid mode, electric-element-only mode, and vacation mode, as well as water temperature.