You can block heat using expensive computer or manually operated shades or by applying colored coatings to glass. Shades are prone to operational problems and use energy. Colored coatings need to be removed to maximize light transmission after the hottest time of the year.
For existing glass greenhouses, another option is to install clear, colorless window film that will block unwanted heat while allowing in desirable natural light. Once installed, such film may last up to 20 years. It does not need to be removed, does not change the appearance or visual clarity of the glass, does not need special care and will not fail to perform because of computer or mechanical malfunction. Affix it and forget it.
The Kool Option
V-Kool 70 clear applied window film reduces solar heat and ultraviolet radiation without significantly reducing visible light or changing the appearance of existing glass. V-Kool clear applied film blocks unwanted heat better than many tinted or mirrored films.
It is installed by professionals at a per-square-foot cost of between $9 and $12 depending on the size and difficulty of the job. V-Kool is reducing the use of air conditioning and energy in thousands of homes and in such landmark buildings as the former headquarters of Montgomery Ward in Chicago, the American Institute of Architects building in Washington and on the campus of Stanford University.
V-Kool Inc., based in Houston, is a sales and marketing distribution company of spectrally selective applied films for architectural, automotive and specialized vehicular applications. For information, visit V-Kool on the Web at www.v-kool-usa.com.