How Polycarbonate Sheets Can Improve Natural Lighting in Buildings

Adding more daylight to a building doesn’t always mean installing more glass. Polycarbonate sheets used in skylights are a lighter and stronger option or a good complement to glass, especially multiwall structures.These are known to provide better thermal insulation compared to a single pane of glass.This mix of good light transmission and improved insulation is why polycarbonate skylights are often used in warehouses, greenhouses, retail spaces, and light industrial buildings.The sections below explain the lighting challenges, how polycarbonate helps solve them, and what to consider before placing an order.

Why Daylight Has Become a Bigger Priority in Building Projects

In the past, daylight design was usually thought of as a pleasant extra.But now, it's becoming more important because of how buildings work.Artificial lighting is one of the main uses of electricity in places like offices and factories.According to the U.S.Energy Information Administration, lighting uses about 17% of the electricity in U.S.commercial buildings, which is the largest single use after "other" categories.This is where roof-level daylighting, skylights, roof strips, canopies, and translucent roofing panels come in.It's not just about making a building look good.It's about using less artificial light during the day.

This applies particularly well to two common building types: Agricultural greenhouses where sunlight influences crop growth and heating requirements, and canopy structures such as carports, garage roofs, and walkways that provide natural lighting and protection from weather elements without requiring the fragility and cost associated with glass roofs.

The Problem With Relying on Glass Alone

Weight, Cost, and Installation Constraints

When one is trying to create an interior that utilizes natural daylight, the first material that comes to mind is glass. But as projects progress, it becomes more difficult to use glass for certain reasons.Glass is a heavy material, thus requiring greater strength in construction, higher installation labor costs, and greater care while transporting.Greater strength requirements due to glass increase costs of materials and labor expenses.

Heat Gain and Glare in Large Glazed Areas

Big areas of glass on a roof can also cause problems with temperature control. A single pane of clear glass usually has a U-value of about 4.8 to 5.8 W/m²K. This means it doesn't insulate well, and it can let heat in quickly in the summer and out quickly in the winter. Plus, it can cause glare if it's not shaded.

That doesn't mean glass is a bad choice.It's just that for many roof and skylight uses, a lighter and better-insulating material might be a better option, especially if the goal is to bring in daylight without all the downsides of using glass everywhere.

How Polycarbonate Sheets Address These Limitations

Light Transmission Without the Extra Weight

Big areas of glass on a roof can also cause problems with temperature control. A single pane of clear glass usually has a U-value of about 4.8 to 5.8 W/m²K. This means it doesn't insulate well, and it can let heat in quickly in the summer and out quickly in the winter. Plus, it can cause glare if it's not shaded.

Polycarbonate is much lighter than glass at the same thickness. It is also much stronger.In fact, it's about 250 times more impact-resistant than regular glass.

Built-in UV Protection and Better Insulation

A common concern with plastic glazing is yellowing over time. Modern polycarbonate sheets address this with a co-extruded UV-resistant layer bonded to the sheet surface, which independent weathering tests report can block up to 99.9 percent of UV radiation under ASTM G154 accelerated testing.

When it comes to insulation, multiwall (hollow-structure) polycarbonate sheets really stand out compared to single-pane glass. Their internal air chambers help them insulate better.These sheets can provide up to 60% more insulation than glass.For example, a twin-wall polycarbonate sheet that's 10 mm thick usually has a U-value of about 2.9 W/m²K.That's better than the 4.8 to 5.8 W/m²K of single-pane glass.

From Natural Light to Lower Energy Bills

The main benefit of better daylighting isn't just about having more light, it's about what happens after: using less artificial lighting during the day.This lowers electricity use and, for many buildings, also reduces the heat from lighting fixtures.

This effect has been studied for many years. A study in the journal Energy and Buildings showed that good daylighting design can cut the use of artificial lighting by 50 to 80 percent. In some cases, total energy savings can be as high as 40 percent for typical office windows. For example, the U.S. Department of Energy reported energy savings of 75 to 80 percent in some federal buildings that used daylighting strategies.

These numbers are general for the whole industry, not for each building.The actual savings depend on factors like the building's direction, local climate, and how the lighting is controlled.But all the research agrees: more usable daylight means less need for artificial lighting during the day, which leads to lower operating costs.

Choosing the Right Polycarbonate Sheet for a Skylight Project

Solid vs. Multiwall Sheets: Which Fits Your Roof Design

Not every skylight project needs the same type of panel.Solid polycarbonate sheets offer the clearest, most glass-like appearance and are often used in places where seeing through is important, such as canopies or display roofs.Multiwall, or hollow, sheets provide a slightly less clear view but offer much better insulation, making them the common choice for greenhouses, warehouses, and large skylights where saving energy is more important than perfect clarity.

Matching Thickness to Climate and Span

The thickness of the sheets also affects how much light gets through and how strong they are. Thinner solid sheets (1 to 2 mm) let through about 88 to 91 percent of light but aren't very strong on their own. Thicker multiwall sheets (8 to 10 mm) let less light through but offer better insulation and can support more weight over longer distances.

A Few Things Worth Checking Before You Order

A short checklist can help avoid more work than a long list of specifications. Before ordering polycarbonate for a daylighting project, it's a good idea to check:

1. UV coating and warranty terms. Ask how the UV protection is added (either mixed into the material or applied on top) and what kind of warranty covers yellowing.

2. Relevant certifications. For projects that go across borders, certifications like ISO 9001, UL, CE, or RoHS compliance can be important for passing through customs and meeting local building rules.

3. Light transmission and U-value data for the exact thickness you're ordering, not just the general product type, because these numbers can change a lot between 6 mm and 10 mm sheets.

4. Supplier production capacity and lead time reliability, especially for large orders where a delay could slow down the whole project.

None of these steps take much time, but they are the little things that often make the difference between a project going smoothly and one that gets delayed.

Conclusion

Getting natural light into a building doesn't usually mean choosing between glass and no light at all.In most cases, the real question is which mix of glazing materials can bring in daylight without adding extra weight, cost, or heat.Polycarbonate sheets, especially multiwall ones, have become a popular choice for this across greenhouses, warehouses, and commercial roofs around the world.

Our company GWX has been producing polycarbonate sheets suitable for use in construction and various industries for over ten years. The production process in our company is compliant with the ISO 9001:2015 standard, while all our raw materials come from trusted manufacturers like Bayer and SABIC. If you are involved in a project that requires skylights or daylighting, we can assist you in choosing the right kind of sheets taking into account climatic conditions and span.

FAQ

1.Can polycarbonate sheets fully replace glass for skylights?
In most situations, yes, but the right material choice always depends on the specific project. Polycarbonate sheets that are solid are suitable for places that require a clear view, while multiwall sheets should be used where additional insulation and impact resistance are required.

2.Do polycarbonate skylights get too hot in summer?
The heat gain depends mostly on color, tinting, and vent placement rather than the type of material used. Tinted multiwall sheets can help reduce heat in sunny regions.

3.How long do polycarbonate sheets last outdoors before yellowing?
Polycarbonate sheets that have an effective UV protective layer on top are specifically designed to have a long lifespan, but their actual life span will depend on weather and quality of the product. It is advisable to ask your supplier about the specific performance of their sheets in varying weather conditions.

4.What thickness is recommended for an industrial roof versus a smaller residential skylight?
The industrial roof requires a thicker multi-wall polycarbonate sheet (8 to 10 mm or more) due to its size and needs for durability. The residential skylight may require the thinner sheet. The supplier can normally help choosing the thickness of the sheet considering distance between supports and climate conditions.

5.Is polycarbonate roofing suitable for coastal or high-humidity regions?
Normally polycarbonate material is good for use in humid or coastal environment as it does not rust. However, the supplier’s test results on resistance to salty water should be considered to confirm suitability of the material in specific area.