A few years ago, I coined the term Engineered Shading Solutions. This is defined as “…sustainable systems for interior and exterior window coverings, which engage the latest technologies to control heat, glare, and light”. While a great deal of the technologies are concerned with the hardware and control systems, the third leg of these engineered solutions are the fabrics. For it is the fabrics that actually control the heat, glare and light.
Engineered for Performance
Solar shade fabrics are a good place to start with the challenge of controlling solar heat gain into a room. In winter, we want the shades raised to allow the solar radiation to heat up the cold spaces. In warmer months, the solar heat gain needs to be controlled.
Solar shade fabric fights solar heat gain on several fronts: openness of weave, color of the fabric, and innovative reflective material. Let’s start with openness. Solar shade fabrics are manufactured with a variety of openness, such as 3, 5, and 10 percent open. A 5 percent openness means that 95 percent of the cloth is closed. As you can imagine, the tighter the weave, the more solar heat gain protection the fabric provides.
In choosing openness, the decision is influenced by the orientation of the windows. Northern-facing windows need the least protection (10 percent openness as suitable). For exposures with direct sunlight, 3 or 5 percent is required to effectively reduce solar heat gain.
Openness of Fabrics from 0% to 14%
The best way to measure performance is by measuring the effects of solar energy upon the fabric. Penetration of the effects of the sun is divided into 3 parts: absorption (AS), reflection (RS) and transference (TS). AS is how much solar energy is absorbed by the fabric. RS refers to the amount of energy reflected by the fabric. TS measure how much solar energy is transmitted through the fabric. The total of all 3 equals 100% of the solar energy at that window.