How Solar Screen Shades Work

How solar shades work diagram

Solar Screen Shades Block the Sun, Not the View!

Solar screen fabric is available in a wide variety of colors, styles, and openness factors to meet almost any criteria.  These fabrics fall into three categories; dark fabrics, light fabrics, and high performance reflective fabrics, all of which provide:

  • Glare Control
  • Heat Control
  • Natural Light Management
  • View-through connection to outside
  • Manage Light
  • UV Protection

High performance solar shades

Insolroll solar shades residential modern living roomHigh performance solar screen fabrics are designed to outperform light and dark fabrics when a project requires excellent heat control, glare control, UV protection and view-through characteristics. High performance fabrics like SilverScreen have a highly reflective exterior regardless of the room-side color. Metallized high performance fabrics are able to provide low visible light transmittance (VLT) values in combination with low shading coefficient (SC) values, independent of color. Typical light and dark-colored solar screen provide a dedicated solution where one or two criteria are required or deemed the most important.

  • For excellent view-through and glare reduction select dark colored fabric
  • For excellent heat management select a light colored fabric
  • For view, glare control, heat reduction select high performance fabric

Dark-colored solar shades

Dark fabrics provide excellent glare control by reducing the visible light that comes through the fabric. Fabrics that block 94%-96% of the visible light provide excellent glare control characteristics, absorb some heat, and keep heat at the window until it dissipates into the room. In applications where passive solar warming and glare control are desired, dark-colored solar screen fabrics are optimal.

  • Higher AS (Solar Absorptance) values mean more light and heat is absorbed,
  • Lower VLT (Visible Light Transmission) values mean less light passes through the fabric, resulting in excellent glare control

Light-colored solar shades

Insolroll solar shades residential kitchen whiteLight-colored fabrics are more effective at reflecting heat, and allow more visible light into the room. Fabrics that block 80-90% of the visible light are an excellent choice for providing more light where windows are small and in common areas where a lighter, brighter ambience is desired. Light is filtered and view-through the fabric is similar to a sheer drapery.

  • Higher RS (Solar Reflectance) values mean lighter colors reflect more heat away
  • Higher VLT (Visible Light Transmission) values mean more daylight is allowed to pass through

How to select the right Solar Screen Fabric

Solar shades control 3 kinds of solar radiation

Solar shades block infrared rays- we feel them as heat

  • Decrease the heat gain through windows
  • Reduce cooling costs
  • Raise shades to any level to take advantage of solar heat gain in winter

Solar Shades Block Visible spectrum Rays: light

  • Decrease glare
  • Increase visual comfort
  • Keep the view! Like looking through sunglasses- glare is reduced and colors are more vibrant and true.
  • View media, work or relax in comfort
  • Stay connected to the outside world

Solar shades block damaging ultraviolet rays (unseen or felt UV rays)

  • Block up to 99% of harmful UV rays
  • Lower risk of skin cancer and cataracts/eye damage
  • Prevent suppression of the immune system
  • Lessen premature aging of the skin
  • Greatly decrease photodegredation (fading and cracking of home materials and finishes)

Understanding solar/optical/thermal factors

Part of the information collectively known as “fenestration data”

Sunlight and solar shade fabric

What is sunlight?

What we call “sunlight” is the energy, or radiation that comes from the sun. Some of it is visible, some is not visible. The visible and invisible combined, or “spectrum”, make up what we see as light, feel as heat, and UV (ultraviolet) rays that are not seen or felt, but have damaging effects on skin, eyes and furnishings.

Solar transmittance (Ts): The proportion of solar energy transmitted through the fabric alone. A low percentage indicates fabrics that reduce solar energy well.

Solar reflectance (Rs): The proportion of solar energy reflected away by the fabric alone. A high percentage indicates fabrics that reflect solar energy well.

Solar absorptance (As): The proportion of solar energy absorbed by the fabric alone. A low percentage indicates fabrics that absorb little solar energy.

All of the available solar radiation is either transmitted through, absorbed by or reflected by the fabric. The total value of all 3 percentages equals 100% of the available solar radiation.

Ts + Rs + As = 100% of solar energy

Openness factor (or Density): Measurement of the relative area of the fabric’s openings, or holes. The more open the fabric, the more solar radiation passes through open space rather than fabric, affecting the overall performance and amount of glare protection, heat protection, and view-through. Fabric color itself does not affect openness across a fabric product line.

Visible light transmittance (VLT): The percentage of the available visible light allowed to pass through the solar screen shade and window combined. VLT is impacted by the openness factor, fabric color, and the amount of light that transmits through the fabric. A low figure (<10) indicates effective glare reduction.

Solar Heat Gain Coefficient (SHGC): Indicates the amount of solar radiation that enters an interior space through both the window and the shade in the form of heat, compared to the total amount of solar radiation.

The lower the SHGC, the more effective a solar screen fabric is at stopping the heat from entering the room.

Shading Coefficient (SC): The previously used term “Shading Coefficient” has been replaced by SHGC, which is a more useful and accurate way of describing the shading effect of shades and all types of windows and glass.

SHGC does not reference single pane, double strength glass, and can be used to calculate energy performance for all times of day and year because it takes the angles of the sun and window treatment into account.

How solar shades block heat

How Solar Screen Shades Block Heat Illustration

  • Some of the sun’s radiation passes directly through the window and shade, bringing heat directly into the space.
  • Some of the heat reflects away from the glass and shade, and some is absorbed, thus heating up the glass and shade.
  • Some of the absorbed heat flows back outside, and some flows inside to the space.
  • The total amount of heat that ultimately warms the space, compared to the total amount of solar radiation before it struck the window is known as the Solar Heat Gain Coefficient, or SHGC.

The heat blocking bottom line

Solar screen shades provide an additional protective layer inside the window glass, reflecting away more of the sun’s heat than the glass alone. The fabric’s density (openness) and color together determine how much of the heat is reflected. Less open fabrics reflect away more heat, as do lighter colors, and high performance fabrics block heat equally well regardless of color.