Case #1: The sun is shining through your glass, pouring uncomfortable amounts of heat into the interior space. You’d like to block this heat (not to mention dangerous ultraviolet radiation) to make the interior space more comfortable, but you love all the natural light and don’t want to darken the space.
Case #2: Your storefront glass needs to be clear so that shoppers can see items on offer, but the heat, rapid sun damage and fading to merchandise and furnishings is unacceptable. Also, the money you’re spending on keeping the space cool is out of line.
Case #3: Your office has people on one side of the building who get an overabundance of sun and heat energy throughout the day. They are always asking for the thermostat to be lowered while people on the opposite side who don’t get that sunshine are complaining that the office is too cold. If you could just block heat on the hot side without blocking too much of the natural light that keeps people upbeat and productive. Workers would be happier and your climate control system wouldn’t have to work as hard or waste so much energy.
What to do? According the the California Energy Commission, solar heat gain through windows, glass doors and skylights dominate cooling loads in buildings. A 2012 study in California showed that solar window film is the most cost effective retrofit for conserving energy.
Traditional solar films block heat and visible light but greater heat protection used to only be available with darker, more reflective films. This works if you have a glare problem as well, but if you’re determined to retain the natural light then spectrally selective window films are the answer. These films target the invisible, infrared portion of the spectrum to block as much heat as possible while allowing natural daylight to wash in. And who would want to save on cooling costs just to spend more on electricity for lighting during daylight hours? Once installed, spectrally selective films are hard to detect as they change the look of the glass so slightly. Blocking up to 60% of the total solar energy, these films can give you the natural light you desire while mitigating the hotspots, discomfort and unbalanced interior climate control that come with it. Available in differing strengths, an appropriate film can be chosen to suit your particular needs.
Additionally these films offer protection from ultraviolet radiation, which has been linked to health problems of skin, eyes, premature aging and immune suppression. Merchandise, floors and furnishings also take a beating from the sun’s rays and especially the ultraviolet portion of the spectrum. Spectrally selective film helps here, too, by blocking 99% of UV, the single greatest factor in sun damage. Blocking heat helps with sun damage as well, as it is another leading factor in fading of furnishings.
Most people think of summer time when considering heat blocking solar film, but winter can be even more of a problem. In winter, the sun stays lower in the sky for more of the day so that more direct heat energy shines through windows rather than on the roof as in summer. Also, the films heat blocking and reflecting properties work in reverse as well, reflecting interior heat so as to keep it inside in winter, which increases the insulating value of the glazing system.
Having window film installed can also provide safety for people in case of glass breakage, with the film acting as a barrier between people inside and broken glass while helping to stabilize the glass and hold it together.
With all these benefits, spectrally selective solar film may just be the natural light preserving, heat and ultraviolet light blocking answer you’re looking for.
Sources: CA ENERGY COMMISSION: Building Envelope Requirements Environmental Health Agency: Health Effects of UV Radiation World Health Organization: Health and UV