A passive integrated collector storage (ICS) solar thermal water heating systems are common in the southern–belt areas of the U.S. An ICS is a self-contained unit integrating the solar collector and hot water storage of 30-50 gallons.

These systems are passive type since no pump or controllers are needed. These units pre-heat mains incoming water before it is routed to the primary water heater storage unit supplying hot water into a building. Some people prefer the simplicity of these systems because there is little or no maintenance required. ICS units can also be plumbed in series to feed tankless electric of gas water heaters where it is boosted to end point of use. Storage on these systems may be a large single tank or a series of four inch (4 in.) tubes, usually copper with selective paint acting as the absorber. Because of the thickness and volume of water contained, chances of freezing are minimized. ICS units do not usually require freeze protection if installed in lower southern regions.  However, outdoor exposed pluming lines to and from the ICS unit may require larger diameter with heavy insulation or freeze valve for protection.  If an ICS unit is used for direct hot water consumption it is mandatory to use an anti-scald valve, whereas used in series with a secondary tank it may not be required.

Installation of an integrated solar water heating collector on a roof requires proper connection to the roof substrate.  The manufacturer-designed attachment kit provides long term and secure attachment to the collector.  It is inappropriate to use other building materials such as wood blocks to mount an integrated collector system. 

To ensure that other components of the home are ready for a solar thermal system, use the following guides:

• Utility Room Space for Solar Thermal Systems
• Mounting Surface for Pumps
• Solar Thermal Bypass Valve
• Solar Plumbing and Wiring Chase
• Architectural Drawing

Install an Integrated Collector Storage Solar Hot Water System

1. Select an approved manufacturer that has been certified and listed by an accredited institution such as the Florida Solar Energy Center (FSEC). Solar systems certified by SRCC (OG-300) may qualify for tax credit or additional rebate incentive programs. The North Carolina based organization Database of State Incentives for Renewable Energy (DSIRE) maintains a data base map for state, local, utility and federal incentives and policies that promote solar renewable energy.
2. Size the solar thermal system accordingly to provide at least 50% of the homes’ water heating energy needs. Solar system selection should be certified by the Solar Rating & Certification Corporation (SRCC), the International Association of Plumbing and Mechanical Officials (IAPMO), or be labeled with Energy Star.
3. A solar thermal collector is preferably mounted on an unshaded southern exposure orientation; however, eastern or western orientations are not to be ruled out. The use of a sun chart or approved analysis tool is recommended to determine seasonal shading.
4. Solar water heating system installations should comply with local building and plumbing codes. Installation should be executed by a trained certified installer. The North American Board of Certified Energy Practitioners (NABCEP) provides a national database on their website that lists certified solar contractors. In addition, the Solar Energy Industry Association (SEIA) provides a map listing of products, companies and solar services.
5. Collector mounting on a roof substrate requires special attention to avoid water intrusion or damage to the roof structure. Builders and installers should take into consideration mounting and positioning of the collector to comply with wind zones, particularly in coastal areas.
6. Plumbing lines to the collector are to be kept at minimal length, preferably at 25 feet, and are usually routed through attics where they are continuous with sleeved insulation. Exterior plumbing lines are also possible with an architectural chase for better appeal.