Solar screen blinds guide

What is a solar screen?

A screen is a textile sun protection that filters sunlight without shutting out daylight completely; it is used indoors and outdoors ^[1]. It is also made as a roller blind, called a “Screen-Rollo” in German and a solar shade in English ^[8][9].

In the common type, PVC-coated glass-fibre yarns are woven into a translucent grid ^[1]. The composition varies: one maker’s fabric is 36% glass fibre and 64% PVC ^[2], another’s 36% glass fibre and 64% vinyl ^[6]; in one catalogue the 4% openness fabric is a PVC and polyester blend ^[8], and another fabric has a polyester micro-yarn base ^[5].

Openness factor and colour

The openness factor shows how tightly the fabric is woven: the lower it is, the more sun is blocked but the less you see outside ^[9][8]. Solar transmittance is largely set by openness, while colour changes the visible light transmittance (Tv), that is, how much glare is reduced ^[10].

Colour matters a lot even at the same openness. In one maker’s 1% fabric, white has Tv 20 and solar reflectance 71, while charcoal grey has Tv 3, solar reflectance 9 and absorption 88 (values in percent) ^[2]. In another maker’s 4% fabric, white has Tv 17 and anthracite Tv 5 ^[5]. Light colours reflect more heat but, with a higher Tv, reduce glare less; dark colours reduce glare more and keep the view out clearer ^[10][9][6].

For one maker, Tv rises with openness in the same colour: its white fabric has Tv 13 at 3% and 17 at 5% openness ^[7][6]. Two-sided fabrics also exist, light on the outside face and dark on the inside: the outer face reflects heat, the inner face reduces glare ^[10].

Data sheet values: Tv, gtot and EN 14501

EN 14501 defines the thermal comfort (solar factor gtot, secondary heat transfer factor, direct solar transmittance) and visual comfort (darkening, glare control, night privacy, visual contact with the outside, daylight use, colour rendering) properties of solar protection devices and their classes ^[11]. The current edition is EN 14501:2021+A1:2025; the 2021 edition has been withdrawn ^[11][12].

gtot is not a value of the fabric alone but of fabric and glazing together; that is why one maker gives two gtot values for the same fabric, one per glazing type (for example 0.34 and 0.25 for white) ^[2]. Compare like with like. The sheet columns are solar transmittance (Ts), reflectance (Rs), absorption (As) and visible light transmittance (Tv) ^[5].

Note: “up to 97%” in a catalogue can be the UV line or a light-filtering claim; they are separate items. In one maker’s sheet the UV line and “97% of light rays filtered (Tv = 3%)” are separate items, and 3% applies only to the darkest colour; the same fabric in white has Tv 20 ^[2]. Another sheet from the same maker says “Tv = 3%” in its heading; in the table only the two darkest colours at 3% openness reach it, while at 5% openness the lowest Tv is 5 ^[3]. Our advice: read the table, not the slogan. These sheets date from 2015 and the maker treats only data on its own website as valid; ask the maker for current values ^[2].

Screen glare in the office

Under the EU rule, windows at display screen workstations must have a suitable adjustable covering to reduce daylight; the rule does not specify the type of covering ^[15]. The UK health and safety authority advises arranging desk and screen to avoid glare and adjusting curtains or blinds against intrusive light ^[13][14].

How much glare a fabric reduces is shown by its Tv, which colour affects: a lower Tv reduces more glare ^[10]. In one maker’s sheet the EN 14501 glare control class of the same 1% fabric is 1 in white and 3 in charcoal ^[2]. Our advice: at screen workplaces choose a low-Tv fabric and plan the desk layout at the same time; a dark fabric fitted inside lets more heat in and reduces daylight more ^[2][10].

Night privacy

According to one maker, by day you can mostly see out while others see in less; at night with lights on inside the effect reverses and people outside can see in ^[9]. Our advice: for privacy at night, add a sheer or drape layer in front of the screen.

In one maker’s sheets the EN 14501 night privacy class is 2 at 1% openness, 1 for a white 5% fabric and 0 in the lightest row of the 10% range ^[2][4]. The maker that describes the night effect writes that a screen on its own works best in shared areas such as living rooms and kitchens rather than bathrooms or bedrooms ^[9]. Our advice: build the layers from the window inwards: blind, sheer, drape.

Inside mounting, outside mounting and ZIP

At home we recommend ceiling mounting: the screen stays in the layer closest to the glass, with sheer and drape in front. Fitted outside, the same fabric lets clearly less heat in: in one maker’s sheet the white fabric has gtot 0.14 outside and 0.35 inside (low-e double glazing, type C) ^[5].

Dark fabric absorbs heat; fitted inside the window, the absorbed heat adds to the heat transmitted ^[10]. In the same sheet, with the same glazing, the anthracite fabric has gtot 0.11 outside and 0.54 inside ^[5]. For exterior screens a common type is the ZIP system, in which the fabric is zipped to the side rail as it is lowered ^[1]; in one maker’s ZIP vertical awning there are no side gaps and wind resistance is class 3 to EN 13561 ^[16]. Internal blinds fall under EN 13120 and external blinds under EN 13561 ^[17].

Fire classification

Fire class depends on the fabric: one maker’s glass-fibre fabric carries European class C-s3-d0 ^[2], another maker’s polyester-based fabric B-s2,d0 ^[5]. Our advice: in public and hospitality projects, ask for the certificate of the fabric you choose.

In EN 13501-1, s3 means the conditions for s1 and s2 are not met, and d0 means no flaming droplets within 600 seconds; the non-combustible class is A1 ^[18]. The German class B1 means “flame-retardant”, not “non-combustible” ^[1]. In one maker’s two-fabric sheet part of the approvals apply to one of them only ^[3]; one maker’s sheet lists only US tests ^[6].

Care and cleaning

According to one maker’s roller blind fabric instructions, dust is removed with a feather duster or compressed air; do not scrub the fabric or use solvents and abrasives; blot stains gently with a sponge or soft brush dipped in lukewarm water with mild detergent, and leave the blind down until completely dry ^[19].

For a polymer-coated fabric the maker asks to avoid paint solvents, bleach and cleaners containing quaternary ammonium compounds or phenols ^[20]. Always follow the instructions on your own fabric’s sheet.

Child safety

Since September 2014 European standards require all blinds to be designed, made and fitted to limit the strangulation risk for children; roller blinds are included ^[21]. Under the EU decision, internal blinds must be of inherently safe design for children aged at least 0–42 months ^[22].

EN 13120 also covers roller blinds ^[17]. The “class 3 EN 13120” seen on sheets is a 10,000-cycle mechanical strength test, not a child safety test ^[2]. For safety requirements see EN 13120:2009+A1:2014, EN 16433:2014 and EN 16434:2014 ^[21].

• Our advice: in homes with children consider a cordless model; a motor removes the operating cord but not the risk from inner cords ^[22].
• On corded models fit the safety device and keep cords out of children’s reach ^[21][22].