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Table of Contents
	Solar Water Heating is Hot, Hot, Hot
	San Antonio Has Its First LEED® Rated Building
	Don't Miss These Green Events
	Texas Legislature Gives TRCC More Power

Solar Water Heating is Hot, Hot, Hot
Want to go solar but looking for a quicker return on your investment? A solar water heater plus Austin Energy's newest solar rebate offering could be your answer.

A Good Investment
Solar water heating systems (also called solar thermal systems) are widely used to provide year-round hot water for residential and commercial buildings. There has probably never been a better time to invest in a system. Although the initial cost of solar water heaters is higher than that of conventional water heaters, the fuel (sunshine) is free, and they create no pollution or greenhouse gases. Heating water with the sun also means being cushioned from future fuel shortages and price increases.

Economic Benefits
There are many benefits to owning a solar water heater, and number one is economics. Solar water heater economics compare quite favorably with those of electric water heaters. An average household with an electric water heater spends about 25% of its home energy costs on heating water. Research conducted by the Florida Solar Energy Center (FSEC) found that solar water heater owners save 50 to 85 percent annually on their utility bills over the cost of electric water heating. Keep in mind that Austin's residential energy code does not allow electric resistance heat as the primary source of water heating in new construction unless it is installed in conjunction with a solar water heating system.

Although the first-cost economics are not quite so attractive when compared to gas water heaters, heating water with the sun is still economically friendly when you consider the long-term benefits. In addition to having free hot water after the system has paid for itself in reduced utility bills, you and your family will be cushioned from future fuel shortages and price increases. You will also be doing your part to reduce our dependence on fossil fuels. The National Remodelers Association reports that adding a solar water heater to an existing home raises the resale value of the home by the entire cost of the system.

Paybacks vary widely, but you can expect a simple payback of 4 to 8 years on a well-designed and properly installed solar water heater. After the payback period, you accrue the savings over the life of the system, which ranges from 15 to 40 years, depending on the system and how well it is maintained.

Environmental Benefits
Solar water heaters do not pollute. By investing in one, you will be avoiding carbon dioxide, nitrogen oxides, sulfur dioxide, and the other air pollution and wastes created to generate power or burn fuel to heat household water. When a solar water heater replaces an electric water heater, the electricity displaced over 20 years represents more than 50 tons of avoided carbon dioxide emissions alone.

Cost Effective and Affordable
According to Solar Utilities Network, solar water heating is the most cost-effective green energy technology available. Solar water heating is an even more affordable solution now that Austin Energy has expanded its rebate program to include solar water heating systems and Congress has extended the available Federal tax credits through 2008. These major savings coupled with a strong base of local, qualified installers make it easy for Austinites to implement this technology.

The Austin Energy Rebate
Austin Energy (AE) offers a rebate or a 0% interest loan to its customers as incentives to install solar water heaters. It's a win-win: customers save on their utility bills; AE avoids the cost of building a new power plant by reducing its peak demand. Everyone benefits from practicing sound environmental stewardship and reducing our dependence on fossil fuels.

All Austin Energy customers with electric water heater systems are eligible for a rebate of $2,000 per solar water heating system. New construction may qualify for up to $1,500 per system. Read all the details, including the eligibility criteria and a list of approved Participating Solar Thermal Water System Installers

The Federal Tax Credit (from the DSIRE web site)
The Energy Policy Act of 2005 (H.R. 6, Sec. 1335) established a 30% tax credit up to $2,000 for the purchase and installation of residential solar electric and solar water heating property. An individual can take both a 30% credit up to the $2,000 cap for a photovoltaics system and a 30% credit up to a separate $2,000 cap for a solar water heating system. Solar water heating property must be certified for performance by the Solar Rating Certification Corporation or a comparable entity endorsed by the government of the state in which the property is installed. Note that the tax credit does not apply to solar water heating property for swimming pools or hot tubs.

Got Sun?
Solar water heaters can be used in any climate, but to take advantage of these heaters, you must have an unshaded, south-facing location (normally a roof). Solar hot water systems should be designed with a solar collection area of 10-15 square feet and 20-30 gallons of storage per person. In central Texas, collectors should be placed facing south and tilted at a 45-degree angle for optimal results. Water-saving faucets and showerheads are recommended to reduce hot-water needs. Typically, a well-constructed solar panel will last twice as long as the roof, if it is installed correctly.

In almost all climates, you will probably want to have a supplemental or back-up hot water supply for cloudy days. Solar water heaters are usually equipped with gas or electric boosters to ensure you are never without hot water. Overall system performance will depend, in part, on how much solar energy is available at the site and on how cold the water coming into the system is. The solar system should be sized to optimize the performance of the system throughout the year, not for worst case extremes. This strategy will avoid unnecessary initial expenses associated with oversized equipment.

How They Work
Solar water heating systems use solar collectors, typically mounted on a roof, to heat either water or a heat-transfer fluid, such as a water-glycol antifreeze mixture.

Solar Collectors
Three types of solar collectors are used for residential applications.

Flat-plate collector
Glazed flat-plate collectors are insulated, weatherproofed boxes that contain a dark absorber plate under one or more glass or plastic (polymer) covers. Unglazed flat-plate collectors (usually used for swimming pool water heating) have a dark absorber plate, made of metal or polymer, without a cover or enclosure.

Integral collector-storage systems
Also known as ICS or batch systems, they feature one or more black tanks or tubes in an insulated, glazed box. Cold water first passes through the solar collector, which preheats the water. The water then continues on to the conventional backup water heater, providing a reliable source of hot water. They should be installed only in mild-freeze climates because the outdoor pipes could freeze in severe cold weather.

Evacuated-tube solar collectors
These collectors feature parallel rows of transparent glass tubes. Each tube contains a glass outer tube and metal absorber tube attached to a fin. These collectors are used more frequently for commercial applications where water will be used for sterilization processes. They are not recommended for our area because of the amount of heat generated by the system.

Storage Tanks
Once the water is heated by the collector, it is stored in a tank similar to a conventional water heater. Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank. The tank could also be used as the collector itself.

Active and Passive Systems
There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't.

Active Systems
Active solar water heating systems are either direct circulation systems or indirect circulation systems (also called indirect water heating systems).

Direct circulation systems
Direct systems circulate potable, household water from the water storage tank through the collectors to heat it and then return it to the tank. They work well in climates where it rarely freezes.

Indirect circulation systems
Indirect systems circulate a non-freezing, heat-transfer fluid, usually a glycol solution, in a closed loop through a heat exchanger which then heats the water that flows into the home. They are popular in climates prone to freezing temperatures. This is the type of system most commonly used in our area.

Another type of indirect system is known as a drain-back system. These systems pump water (usually purified) in a closed loop using a heat exchanger to heat household water inside a tank. When not in use, the system uses gravity to drain the purified water into a tank to avoid any issues with freezing and overheating. The pump is reactivated when the temperature of the collector panels becomes higher than that of the water in the tank.

Passive Systems
Passive solar water heating systems are typically less expensive than active systems, but they are usually less efficient. However, passive systems can be more reliable and may last longer. There are two basic types of passive systems:

Integral collector-storage passive systems
These systems are a tank and collector in one. Hot water is drawn from the top of the solar collector and flows to a second tank. Meanwhile, colder water flows on demand into the bottom and is ready for heating. These work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot-water needs.

Thermosyphon systems
Water flows through the system when warm water rises as cooler water sinks. The collector must be installed below the storage tank so that warm water will rise into the tank. These systems are reliable, but contractors must pay careful attention to the roof design because of the heavy storage tank. They are usually more expensive than integral collector-storage passive systems.

A Homeowner's Point of View
The Benavides' five-star green home includes a solar hot water heater that, according to the homeowners, has been working very well. The indirect, drain-back system with a flat-plate solar collector was installed by Techsun Solar Water Systems. The family has a remote device that monitors and displays the temperature of the water in the tank. The system adjusts between the solar and electric heating so there is not really any possibility of not having hot water.

Home designer/builder Khair Zaman of ZWorks Design/Build feels that there are some good lessons to be learned from the Benavides' story. Zaman carefully sited and designed the home to include a 3 Kw solar electric system. Because of the photovoltaic system, the homeowners chose to have an all-electric house with very efficient appliances. Typical electric water heaters use a lot of electricity and when it came time to install the water heater, the Benavides' found out that a City of Austin code amendment requires all-electric homes to use a heat pump, a heat recovery system, or have solar pre-heated water. Luckily, the roof was properly oriented for solar energy collection; unfortunately, space was at a premium in the home and the back-up 30 gallon water tank had to be installed in the attic.

Resources
DOE EERE Consumer's Guide
NREL National Renewable Energy Laboratory
Toolbase Solar Water Heaters
Arizona Solar Center
SEI Solar Hot Water Workshops
Austin Energy Solar Rebate Program

San Antonio Has Its First LEED® Rated Building
San Antonio's City Council recently passed a resolution requiring that every new municipal building must earn at least a Silver LEED® rating. Zachry Construction Corporation, a San Antonio-based company, raised the bar on that Silver rating by earning a LEED Gold rating on their latest project: renovating a 20,000 square foot brick warehouse into a Gold-rated corporate headquarters. The $5 million renovation cost about 15 percent more than a non-green building, said Rene Garcia, head of the company's commercial building division. Garcia noted, though, that the energy savings would offset the extra construction costs within five years. The building is over 25% more energy efficient than a typical office building. It uses a daylight harvesting system to adjust electric lighting and supplies 5.5% of its energy use with solar photovoltaics.

Other green building technologies include:

	Rainwater is harvested for flushing toilets; and a gray-water system collects water from sinks, fountains and showers for landscape irrigation.
	The standard asphalt parking lot was replaced with gardens, crushed granite and permeable concrete.
	Much of the building was constructed using recycled materials, salvaged goods and renewable materials, including boards made from wheat chaff, cork flooring and fabric wall coverings made from grasses.
	90 percent of the deconstruction materials were salvaged and donated to churches and nonprofit groups or sold for reuse, saving 679 tons of waste — more than 11/2 times the weight of a Boeing 747 airplane — from being landfilled.

Goetting and Associates provided the mechanical, electrical and plumbing (MEP) engineering for this project. Goetting and Associates is a member of the USGBC and has 6 LEED® Accredited Professionals on staff.

Read the MySanAntonio.com article about this building.

Don't Miss These Green Events
Put on your sustainable party hat: four fun, fabulous green events are just around the corner.

Renewable Energy Roundup
If Austin seems a little lonely over the weekend of September 28-30, it's probably because everyone in town is attending the ever-popular grand-daddy of green festivals held in downtown Fredericksburg. The Roundup is known for its excellent exhibits, booths, and speakers. There's also activities for the kids and plenty of food and fun for all. Stop by the AEGB booth and say hi.

AEGB staff, Dick Peterson, will present his popular Rainwater Harvesting Basics seminar. Other sure-to-be-excellent presentations include:

Green City Fest
On Saturday, October 13, the City of Austin will host its first Green City Festival from 10-4 at City Hall. Be there at the first of what may become an annual city tradition. This fun and informative day is suitable for the whole family. Learn about the City's environmental programs, rebates, and more. Nine City departments and 40 partnering non-profit organizations will provide a fun, informative day for the entire family with educational talks, music, a hands-on Kids Korner and more. You will learn how to save money by using City rebates, participate in hands-on workshops, hear speakers on green building, gardening and some of the latest in emerging green technologies. You can also attend a WaterWise talk and be eligible to register for a free Honda.

Natural Building Colloquium
Quiet Valley Ranch, home of the long-running, world famous Kerrville Folk Festival, will host the Natural Building Colloquium from October 19 - 28, 2007. Everyone is welcome, whether experienced with natural building or simply curious to know what it's all about. You can come for the whole 10 days or just a weekend.

Austin's Design~Build~Live (formerly the Sustainable Building Coalition) and other Texas natural building leaders will work with colloquium participants to improve facilities used by Kerrville Folk Festival artists, staff and visitors. In the works are a cob/native timberframe entry booth with earthen and lime plasters, an earthen oven, a kid-sized cob cottage with a living roof, and possibly a strawbale and light-clay-straw office space.

Confirmed presenters include David Eisenberg, Penny Livingston-Stark, Sun Ray Kelly, and many other amazing natural building experts. The web site has the latest information on speakers, schedules, and other colloquium details.

Sustainable Shopper's Ball
Christmas is coming, and so is the next Sustainable Shopper's Ball. We'll see you on December 1 at the Toney Burger Center (where the Sunset Valley Farmer's Market is held). Austin's homegrown sustainable living fair includes exhibitors, speakers, music, and best of all, shopping! The Sustainable Shopper's Ball continues to build on its hugely successful events of 2006. The dedicated all-volunteer organization has created a fun, inclusive and inspiring event that promotes Austin's local, sustainable businesses.

Texas Legislature Gives TRCC More Power
The Texas Residential Construction Commission (TRCC) was created by the Legislature in 2003 to, among other things, assist in disputes between homebuilders and homeowners.

House Bill 1038, recently passed by the Legislature, made many changes to the TRCC. Registration requirements for builders and remodelers are different, as is the commission’s regulatory authority. HB 1038 gives the commission more disciplinary authority by allowing TRCC to penalize builders who do not register with the state and fine builders up to $100,000 for fraud or misappropriation of funds.

Other new provisions include:

	Remodelers or builders must register with TRCC if contracted to a project costing $10,000+ (decreased from $20,000)
	Builders must now also provide for inspections of residential construction in unincorporated areas
	Building permits can not be issued to unregistered builders

Resources
TRCC Compliance Advisory