Why Solar Water Heating?
Floridians see their electric bills go through the roof during July, August and September and don’t need to be told that air conditioning uses a lot of electricity. At today’s electric rates (including fuel surcharges and utility taxes) of around 14 to 15 cents per kilowatt hour, water heating can easily cost $800 to $1,200 each year for a three to five person household. In Central Florida, a solar water heater can almost completely eliminate this portion of your electric bill.
Solar water heaters offer many extra benefits
Naturally, switching to solar water heating means going green in a big way. but you might also be surprised to learn that solar water heating gives you benefits that improve upon conventional electric or gas water heaters:
- More hot water. Solar storage tanks are sized to store an entire 24 hour’s worth of hot water because there is no sunshine at night.
- Hotter water. The water delivered by a solar collector panel can be hotter than the thermostat setting on your electric water heater.
- Plenty of hot water during emergencies. With a passive solar water heater, or a system with a solar-powered circulating pump, you will have your customary supply of hot water even during electric power outages.
- Qualifies for the 30% federal tax credit
Which home energy uses are the most expensive?
The pie chart below shows where the money goes in a typical Florida family’s annual electric bill. The chart is based upon an electric power consumption study by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. The “typical” Florida household and energy use pattern shown above is based upon these factors:
- Florida home built in 1990 with 2,400 square feet of living area
- 9.5 SEER air conditioner with thermostat set at 81°F during day and 78°F at night
- cold weather thermostat setting of 64°F during day and 68°F at night
- two adults and two children in household
- 80 gallons of hot water per day
- 14 cents per kilowatt-hour electric cost (including fuel surcharge and utility taxes)
- Reduces Dependence On Fossil Fuel and Foreign Oil
- Reduces Co2 And Sulfur Dioxide Emissions
- Qualifies For Up To $2000 In Federal Tax Credits
- Qualifies For Many Utility Company Rebates
- Exempt From Florida State Sales Tax
- Protects From Future Rate Increases
- Increases Property Value
- Provides Hot Water During Power Outages
- Tax-Free Savings
*Mechanical Engineering Department, University of Wisconsin-Madison
Is your hot water use average?
Actually, an active American family of four is probably closer to 100 gallons per average day and just over $1,000 per year at 14 cents per kilowatt-hour.
Because incoming solar radiation—called insulation—is often interrupted by cloudy or rainy weather and fluctuates in intensity with seasonal changes in the sun’s position in the sky, solar water heating systems are usually sized to collect and store an entire 24 hours or more worth of energy to meet hot water demand. A modern solar water heating system storage tank will usually have a backup electric heating element to meet unusual peaks in hot water use or extended periods of very cloudy or rainy weather.
Will my water be hot enough?
Yes. Solar heated water is often hotter than the thermostat setting on your water heater. In fact, for safety reasons our systems include mixing valves to make sure the hot water going into your house isn’t too hot. On the other hand, sometimes we may have extended periods of very cloudy and rainy weather. During these periods, a backup electric heating element in your water heater / storage tank will automatically heat water to the water heater’s thermostat setting.
Will I have hot water during cold weather?
Yes. Solar water heating collectors typically deliver excellent performance in Florida during cold weather because the sky is very clear during winter high pressure waves. The glass cover plate and insulation inside the collector prevent collected heat from escaping to the outside air.
Can you use my existing water heater as the solar storage tank?
Usually, no. Solar water heating systems are designed to heat and store 24 hours worth of hot water during the daylight hours, so the tank has to be large enough to store 24 hours’ worth of hot water. Most conventional electric water heaters in Florida homes have a capacity of about 52 gallons. Standard solar storage tank sizes are typically 80, 100 and 120 gallons, with 80 gallons being appropriate for most three- to four-person households. Also, solar storage tanks typically have better insulation than conventional electric water heaters, to minimize overnight heat loss