Solar Water Heating
USING SOLAR ENERGY FOR RESIDENTIAL WATER HEATING
Using energy from the sun to heat water is one of the oldest uses of solar energy. Today, several million homes and businesses use solar water heating systems. These systems are providing consumers a cost-effective and reliable choice for hot water. How you heat the water for your home is an important consideration. The U.S. Department of Energy estimates that you will spend over $500.00 a year to heat water with electricity in an 80-gallon tank. When considering a solar water heater, you may ask: How is a solar water heater competitive with conventional heaters? How does a solar water heater work? What about maintenance? Do I live in an area with enough sun to heat my household’s water?
HOW IS A SOLAR WATER HEATER COMPETITIVE WITH CONVENTIONAL HEATERS?
Prices for complete solar water heating systems range between $4,000 – $7,000 depending on your hot water requirements and the climate conditions in your area. Federal tax credits will reduce this cost by 30% up to a maximum credit of $2,000. This is a higher initial investment than required for an electric or gas heater but when you add all of the costs involved with heating water in your home, the life-cycle cost of a solar water heating system is at least 20% lower. Remember that your system runs on an energy source that is free! Savings can be even greater if you are building a new house and the system cost is included in the mortgage.
HOW DO SOLAR WATER HEATERS WORK?
In a solar water heating system, a heat-transfer fluid flows through the tubes of solar collectors, where it is heated and transfers the heat to the household water. The heated water is then stored for use in a tank. A solar water heating system can be used as the sole source for hot water or may include a back-up conventional system to meet heavy or unusual hot water requirements throughout the year. Systems are usually sized according to the number of bedrooms, people and household water needs. There are several different configurations of solar water heating systems. In general, however, there are two main types: active systems which have pumps and controls to deliver solar heat to the storage tank, and passive systems which combine the collector and storage in a single unit.
WHAT ABOUT MAINTENANCE?
The simplicity of solar water heating systems means that maintenance is minimal. Required maintenance will depend on what type of system you own. Solar systems should be designed for your local climate conditions. An important consideration when designing a system is the freeze-protection requirements. The size of the industry and the variety of available solar water heating systems means that you can find a system that is appropriate for your region. All solar systems will provide significant savings all over the United States. There are a number of Qualified solar water heater installers and distributors in your area who can determine and provide the most appropriate system for your house. To ensure high quality and satisfactory performance of solar water heating systems, authorized rating and certification programs have been established to test systems, rate their performance, and ensure the integrity of their design. These criteria have been established to assure customer satisfaction and to simplify the purchase of a system. A solar water heater will save you money but it will also help protect our environment. One to two tons of carbon dioxide are generated by a single conventional water heater every year. Other pollutants, such as sulfur dioxides, carbon monoxide and nitrous oxides are also displaced when a homeowner decides to tap into a cleaner source of energy – the sun.
California’s New Solar Water Heating Incentive Program
The California Solar Energy Industries Association actively participated in creating and designing this program. Since 1977, CALSEIA has represented California’s most experienced and reputable solar water heating companies, all of whom abide by the CALSEIA Code of Ethics. If possible, you would be wise to hire a CALSEIA company.
Pacific Gas and Electric Company, Southern California Gas Company, Southern California Edison Company, and San Diego Gas and Electric Company (SDG&E) will pay cash incentives for installing solar water heating systems within their service territories. (Publicly owned utilities may also support solar water heating, but their incentive programs are not discussed here.)
All of the investor-owned utilities named above administer their solar water heating incentive programs, except SDG&E. The California Center for Sustainable Energy is program administrator for SDG&E’s solar water heating program.
You can identify which entity is your solar water heating program administrator by determining which utility currently provides electricity or natural gas service to your water heater. (Customers using propane water heaters are not eligible to participate in their electric utility’s incentive program.)
The incentive is a cash, lump-sum payment based on a calculated estimate of how much natural gas (measured in therms) or electricity (measured in kilowatt-hours or kWh) you could save annually by installing a solar water heating system. The utility will send the incentive check after your solar water heating system has been installed and inspected.
Large-scale solar water heating installations on multifamily and commercial projects (250 kWth or greater) will receive their incentive payments in two stages: 70 percent as soon as the system is installed, inspected, and ready to operate; and up to 30 percent more, after one year’s monitoring confirms actual performance matched or exceeded estimated savings.
Up to 60 percent of the incentives will be paid for installations on multifamily and commercial facilities and at least 40 percent will be paid for single-family projects. Incentives for solar water heating projects on low-income homes, including mobile homes and low-income apartments, will receive up to $25 million.
Note that incentive levels will reduce as more and more people participate in the program. If an incentive level drops while your incentive application is pending, you will be notified. As of October 2010, the current rebate is $12.82 per therm or $0.37 per kWh up to a maximum of $1,875. The total incentive is based on a combination of the performance rating of the solar water heater, the orientation of the collectors (you will receive closer to the maximum rebate if they are facing true south), your regional climate, and whether the solar panels will be shaded (collectors should be shaded as little as possible)
Large-scale multi-family and commercial solar water heating system may receive up to $500,000 if they are displacing natural gas or up to $250,000 if they are displacing electricity.
The incentive payment can’t be greater than your out-of-pocket expenses, which may include the following: design and engineering, construction and installation, solar equipment and ancillary equipment, permitting fees, and sales tax. (Note: Installing a solar water heating system does not increase your property taxes.)
Other Solar Energy and Energy Efficiency Incentives
In addition to this incentive, you may still be eligible to receive a cash grant from the American Recovery and Reinvestment Act’s “Cash for Appliances” program, which is administered by the California Energy Commission, for installing a solar water heater. (See http://www.cash4appliances.org/.)
You may be eligible to receive an energy-efficiency rebate for replacing your old water heater. (You would use it as a back-up to your solar water heating system).
You may also be eligible for the federal solar tax credit of 30 percent for the total installed cost of the system. (See the answer to the fourth question at http://www.irs.gov/newsroom/article/0,,id=211307,00.html.)
Solar Shopping Tips
Below are some tips on how to shop for a solar water heating system and participate in this cash-incentive program.
Perform or have performed an energy audit to determine or estimate:
- Whether you are currently heating water with natural gas or electricity,
- Location, size, and age of your current water heater and its rated energy efficiency,
- Approximately how many gallons of hot water you use daily, and
- What energy and water-efficiency measures would be cost-effective to install to reduce your hot-water use.
Gather your utility bills from the past 12 months to determine or estimate:
- Whether and by how much each month’s bill typically includes charges for energy consumption above baseline rates,
- How much you pay annually for hot water service. (If your winter natural gas bills include consumption for both water and space heating, consult your summer natural gas bill for a better estimate of monthly gas use for water heating and its cost.)
Evaluate your roof for compatibility with a solar water heating system:
- How much square footage is available on the south-facing side of the roof?
- Do trees shade portions of the south-facing roof?
- Are there vents and other roof penetrations that would complicate where collectors could be placed?
- Can the roof support a solar water heater now or would it need reinforcing?
Contact at least three solar companies to obtain their opinions on the feasibility of installing a solar water heating on your roof and learn what type of solar water heating system they would recommend installing and why.
After choosing a solar contractor, don’t agree to pay a large, up-front deposit. California contractors law limits the deposit to no more than $1000.
To know you are working with an experienced solar professional, ask these questions:
- Does the contractor have a valid license (for example, C-46) from the Contractors State Licensing Board to install solar water heating equipment?
- Has the licensed contractor attended the mandatory training regarding the Solar Water Heating Program within the past 12 months? (Listed as an eligible contractor at the gosolarcalifornia.org website.)
Has the licensed contractor previously installed solar water heating systems under this incentive program and did the utility’s inspectors fail any of these installations and require corrective action before paying the cash incentive?
- Has the solar water heating system been rated by the Solar Rating and Certification Corporation?
- Does the system come with the required 10-year manufacturer’s warranty against defects and 15-percent degradation of system performance?
- Has the solar contractor “right-sized” the solar collectors’ square footage?
- Given the coldest recorded temperature for your climate zone, does the solar water heating system have appropriate freeze protection?
- If you were away for several days (for example, on vacation), does the solar water heating system have appropriate stagnation/overheating protection?