What Openness Factor Should a Zip Screen Fabric Have?

The Short Answer

The openness factor is the percentage of a screen fabric's surface that is open space between the yarns. A lower figure such as 1% or 3% gives more glare control and daytime privacy but a softer view; a higher figure such as 5% or 10% keeps more of the view and lets in more light. There is no single correct value: choose it from the sun exposure, the view and the privacy each opening needs, then confirm it with a sample in the fabric colour you will actually order.

Two fabrics with the same openness can still behave quite differently, mainly because of their colour. This guide explains how to read the number and use it on a real project.

What the Openness Factor Measures

Openness describes the geometry of the weave, not the overall performance of the fabric.

Open area, not total light

A fabric sold as "5% open" has about 5% of its surface as holes. Light passes straight through those holes, which is what lets you see outside. But light also passes through and scatters off the yarns themselves, especially pale ones. So total light transmission can be noticeably higher than the openness figure, and a white fabric can feel much brighter than a charcoal one with the same openness.

Why "3% open blocks 97% of UV" is only shorthand

Openness is often converted directly into a UV-blocking percentage. That is a rule of thumb for UV passing through the holes, not a test result. If UV performance matters, ask for the measured value on that fabric's data sheet.

What openness does not tell you

The figure says nothing about the fabric's strength, durability, fire behaviour or heat performance. Nor does it guarantee insect protection, which depends on the size of each hole and any gaps around the screen. Check these separately.

Openness Levels at a Glance

The table shows the general trade-offs. These are relative comparisons, not test values; the result depends on the fabric, its colour and the site.

Not every fabric range is sold in all of these steps, so compare data sheets rather than marketing names.

How to Choose Openness for an Opening

Start from what the people behind the screen will do there, not from the fabric catalogue.

Start with sun exposure

Openings that take direct low sun, such as west-facing terraces in the late afternoon, usually benefit from a lower openness or a darker colour, because low sun shines straight into people's eyes. Openings that are shaded by a roof, a neighbouring building or a deep pergola can often use a more open fabric. Think about the worst hour the space is actually in use.

Weigh the view against privacy

A sea-view restaurant and a street-level café want different things from the same fabric. Where the view sells the space, keep the openness as high as glare allows. Where neighbours or passers-by look in, go lower. A view through a screen is also generally clearer from close to the fabric than from the back of the room.

Remember that privacy reverses at night

A screen fabric hides the bright side from the darker side. By day, the people in the shade can see out, while people outside see less. In the evening, when the terrace lights are on and it is dark outside, this reverses and the lit space becomes visible from outside, at any common openness. If evening privacy matters, as on many villa terraces, an open-weave screen alone will not solve it. Specify a more closed fabric for those openings.

Decide how to treat the whole project

Different openness per elevation can help comfort, but a facade seen from the street usually looks best with one consistent fabric. Try one fabric across all openings first and vary it only where a real problem justifies the visual difference.

Why Fabric Colour Can Matter as Much

Colour is the variable most often left out of the openness conversation.

Dark colours and the view

Dark fabrics absorb more light, so looking out through them is generally easier. Light fabrics scatter more light across their surface, which can look bright and hazy from the shaded side and often gives less glare control at the same openness.

Light colours and heat

Light colours reflect more solar energy. For an outdoor screen, though, the comparison is different from an indoor blind. An outdoor fabric stops the sun before it reaches the glass or the seated guest, and heat the fabric absorbs is largely released to the outside air. Where heat performance matters, ask for the data of the actual fabric instead of relying on colour alone.

Appearance from the street

Colour also sets how the screen looks from outside, which is often what the owner judges first. Compare fabric and profile colours together, and see our supplier guide for pergola and awning companies for coordinating them with the frame.

When Openness Does Not Apply

Openness applies to woven or mesh screens. Other zip screen fabrics work differently.

Transparent PVC

Transparent PVC is a closed film with no openness at all. It keeps the view while closing the space against wind, dust and rain, which suits restaurant terraces in the cooler season. Because no air passes through, the space behind it can feel enclosed in warm weather, so operable openings and ventilation should be considered. Our zip screen blinds page shows the PVC options.

Closed fabrics

A closed fabric has effectively no view through it. It gives the strongest privacy and shade, including at night, but makes the space feel more enclosed. One option is to use it only on the side facing a neighbour.

Choosing between the fabric types

Our zip screen vs outdoor roller blind comparison covers the system itself. For the fabric, the priority decides the type:

How to Check a Fabric Before Ordering

A percentage on a page cannot show how a screen will feel on site.

Read the data sheet

For screen fabrics, ask for the openness figure and, where available, the measured values for light and solar transmission and reflection. In Europe, EN 14501 is the reference for classifying the thermal and visual comfort of blinds and shutters, so a supplier may present results in those terms. Check that any figures refer to the exact fabric and colour offered, not just the range.

Test samples on site

Hold the sample in the real position, at the real time of day:

• From the seated position: look through it at the view from where guests will sit.
• At the worst sun hour: check glare when the sun is lowest in the opening.
• In the evening: with the area's lights on, step outside and see what is visible.
• In the final colour: a sample in another colour tells you little about the one you plan to order.

Record the fabric and plan for cost

Cost depends on the fabric's construction as well as the size and quantity of screens, so openness alone will not predict the price. Note the fabric reference on your opening schedule so a later replacement can be matched. For coastal and high-sun sites, see our guide to blinds for Mediterranean and Gulf climates.

How We Supply Zip Screens

LuxiVeil is the export brand of Gökcan Home, a curtain and blind manufacturer producing in Antalya, Türkiye, since 1994. We make zip screen systems to measure in our own workshop and send fabric and colour samples for approval before production. We do not quote a general openness recommendation for every project: tell us the view, shade and privacy you need per opening, and we will confirm which fabrics and specifications are available for it, with the fabric's documentation where it exists. There is no fixed minimum order, and trade partners can read how we work on our wholesale blinds page.

Frequently Asked Questions

What does openness factor mean on a zip screen fabric?

It is the percentage of the fabric's surface that is open space between the yarns. A 5% fabric has about 5% open area. A higher figure generally gives more view and light, and a lower figure more glare control and daytime privacy.

What openness is best for a restaurant terrace?

There is no universal answer. Sunny terraces often look at lower openness levels for glare control, while shaded terraces with a good view can use more open fabrics. Test a sample at the seating position at the worst sun hour before deciding.

Does a lower openness always keep the space cooler?

Not by itself. Openness is one factor; colour, fabric construction, the sun angle and whether the space is enclosed or open also affect comfort. Compare measured data for the actual fabric where heat performance matters.

Can people see through a screen fabric at night?

Often, yes. When the terrace is lit and it is dark outside, people can see in. Use a more closed fabric where evening privacy is required.

Does transparent PVC have an openness factor?

No. Transparent PVC is a closed film, so no air passes through it. You choose it for keeping the view while closing the space, rather than for a level of openness.

Request Samples or a Quote

If you are specifying a terrace, pergola or hotel project, send us the width and height of each opening, the mounting situation, what matters most at each opening (view, shade or privacy), your colour preference, the operation and the delivery address. We will review each opening, send fabric samples for approval and return a quotation per screen. Use the quote form on our contact page, or message us on WhatsApp for a quick first answer.