Polycarbonate is far more impact-resistant than glass and about half its weight at the same thickness, while glass is harder to scratch and keeps its surface longer. Polycarbonate and glass solve different glazing problems. If impact exposure, on-site cutting or handling weight drives the brief, start with a specified solid PC sheet and its fixing system. If long-term scratch resistance and a conventional glass finish dominate, ask a glazing designer for the appropriate glass build-up. Compare the installed assemblies before approving either option.
Ask for a PC glazing quote See PC glazing applications
Which difference matters to your project?
Use this as a shortlist, then request grade-specific data and an installation detail. “Glass” can mean ordinary float, tempered, laminated or insulated glazing; those are not interchangeable specifications.
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| Decision point | Solid polycarbonate sheet | Glass glazing | What to verify |
|---|---|---|---|
| Impact and breakage | A PC grade can be selected for impact exposure, but the rating depends on thickness, grade, test and retention detail. | Tempered and laminated glass address different breakage and retention requirements from ordinary float glass. | Named hazard, required standard, panel opening, support and complete assembly test. |
| Surface and cleaning | Uncoated PC can scratch under abrasive wiping; consider a specified hard-coated PC grade when cleaning wear matters. | Glass generally offers a harder surface for routine cleaning, subject to coatings and cleaning instructions. | Cleaning chemicals, abrasion exposure and surface warranty for the offered product. |
| Handling weight | Representative solid PC density is 1,200 kg/m³; a nominal 6 mm sheet calculates to about 7.2 kg/m². | Ordinary soda-lime float glass density is about 2,500 kg/m³; nominal 6 mm single glass calculates to about 15 kg/m². | Actual grade, glass build-up, dimensions, tolerances and frame/hardware mass. |
| Light and view | Clear solid PC can provide direct view; tint, texture, thickness and UV package change appearance. | Clear glass can also provide direct view; tint, low-E coating, laminate and unit build-up change appearance. | Like-for-like visible-light transmission and haze for quoted configurations, preferably physical samples. |
| Heat and weather | Specify the UV-protected side or sides and installation orientation, thermal movement allowance, edge clearance and compatible fixings. | Specify glass type, coatings, seals, edge support and movement in the glazing system. | Assembly U-value, condensation, loads, seal compatibility and local code. |
| Making to drawing | PC can be cut, drilled and formed for a custom opening; holes, bend radius and stress control need review. | Glass processing and safety treatment follow the selected glazing build-up and fabricator sequence. | Drawing, holes, edge finish, tolerances, minimum radius and on-site fitting plan. |
Worked example: the weight of a 6 mm panel
At the same nominal 6 mm thickness, area mass is density × 0.006 m. Representative solid PC: 1,200 × 0.006 = 7.2 kg/m². Ordinary single-pane float glass: 2,500 × 0.006 = 15 kg/m². A 1.2 × 0.8 m panel (0.96 m²) therefore weighs approximately 6.9 kg of PC or 14.4 kg of float glass before framing. PC is about 52% lighter in this narrow material-only example.
6 mm single float glass · 15 kg/m²
Inputs: SinoPlastix solid PC density, representative grade, ISO 1183-1; Pilkington soda-lime-silica float-glass density bulletin. This arithmetic does not establish equal strength, safety classification, allowable span, impact protection or installed-system performance. Tempered, laminated and insulated glass units need their own mass calculation.
Impact strength: what the “250 times stronger” claim means
The “250 times stronger than glass” figure is widely repeated, but it is not a single test result. Polycarbonate and glass are not normally tested by the same impact method, so the ratio depends on which numbers are compared.
What can be stated with a method attached: a representative SinoPlastix solid PC grade records 921 J/m notched Izod impact (ASTM D256, 3.2 mm specimen, 23 °C). Annealed glass is brittle and fails at a small fraction of that energy; tempered and laminated glass change how glass breaks and is retained rather than turning it into a tough material.
For a buying decision, ask for the impact test that matches the hazard, for example a ball-drop or pendulum test of the mounted panel, or EN 356 for manual attack on a glazing build-up, rather than a multiplier. See is polycarbonate bulletproof? for ballistic ratings.
Insulation: U-value of polycarbonate vs glass
Single solid sheets insulate about the same whatever the material, because the still-air layers on each face do most of the work. Using the same EN ISO 6946 method for vertical glazing, U = 1 / (0.13 + 0.04 + d/λ):
| Glazing | U-value (W/m²K) | Basis |
|---|---|---|
| 4 mm single float glass (λ = 1.0 W/mK) | ≈ 5.8 | Calculated |
| 6 mm solid PC (λ = 0.21 W/mK) | ≈ 5.0 | Calculated |
| 10 mm twinwall PC, named product (Marlon ST) | 3.20 | Published by the manufacturer |
| 16 mm fivewall PC, named product (Marlon ST) | 1.90 | Published by the manufacturer |
The real insulation gain comes from multiwall PC, whose air chambers lower the sheet U-value. An insulated glass unit is the glass equivalent and needs its own published value. Compare installed-system values, including frames and edges, before choosing. See the PC U-value guide for the method and sources.
Cost: compare the installed system, not the sheet price
A square metre of polycarbonate sheet can cost more or less than a square metre of glass depending on grade, thickness, coating and order size, so a sheet-price comparison rarely decides the project. Compare these lines for the same opening:
- Material: the quoted PC grade, thickness and finish against the glass build-up actually required (float, tempered, laminated or insulated).
- Frame and support: 6 mm PC at 7.2 kg/m² against 6 mm glass at 15 kg/m² may allow a lighter frame; confirm it by a structural check, not by assumption.
- Handling and installation: cutting and drilling PC on site against factory-processed glass, lifting equipment and breakage in transit.
- Replacement risk: expected breakage or scratching in the actual use, and the cost of a replacement panel.
- Energy: only where an insulating multiwall sheet or glass unit is being compared.
For a priced comparison, send the opening sizes, quantity and the glass specification you are replacing; see how wholesale pricing works.
Bending and curved glazing
Solid and multiwall PC can be cold-curved on site into a frame-held, single-direction curve, within the minimum radius the grade’s installation guidance allows. Glass needs factory heat-bending for any curve. Where a tighter or compound shape is needed, PC can be heat-formed. See bending and forming for what to send.
When PC is the better quotation route
- Impact-prone screens and machine windows: send the hazard and target standard. We can propose a solid PC grade, thickness and guard configuration for review; a sheet alone is not a certified guard.
- Lightweight replacement or hard-to-handle panels: share the opening and frame drawing so material mass, deflection and fixing can be evaluated together.
- Custom-shaped glazing: provide the cut file, drilled holes, bend requirement and acceptable appearance. See PC fabrication.
When glass deserves the first review
For a high-touch surface with frequent abrasive cleaning, or an architectural system that already specifies a tested glass unit, retain the glass specification as the reference. Compare hard-coated PC only if the project has a reason to change the material. For fire, security or fall protection, ask the designer to define the required whole-system rating; neither generic PC nor generic glass can be substituted by a material slogan.
Send a drawing for an answer you can use
Include panel dimensions and quantity, application and impact exposure, existing glass build-up if replacing it, indoor/outdoor location, desired clarity or tint, cleaning method, support/span and fixing drawing, holes or formed features, destination and required test standard. Ask for the proposed PC grade, sheet mass, relevant reports, tolerances and fixing assumptions. Common test reports are available through sales on request. The written quotation confirms custom specification, actual price and lead time; website averages are planning references.
Send your glazing drawing Build a material brief first
Questions buyers ask
Which is better for a greenhouse: polycarbonate or glass?
Multiwall polycarbonate is common for greenhouses that need insulation, diffuse light and hail resistance; glass gives the clearest light and the longest-lasting surface. Compare the light transmission, U-value and support spacing of the actual panels against the crop and heating plan. See greenhouse PC panels.
How long does polycarbonate last compared to glass?
Glass does not weather in sunlight. Polycarbonate’s outdoor life depends on its UV-protected surface, installation orientation and exposure; ask for the written UV and weathering terms for the offered sheet, and install the marked UV face outward.
Is polycarbonate always stronger than glass?
No universal multiplier is useful without naming the PC grade and thickness, glass construction, test method and installed support. Describe the actual impact hazard and required standard so the proposed assembly can be checked.
Does lighter PC mean I can reuse the same frame?
Not automatically. Although the 6 mm material-only example is lighter, stiffness, deflection, thermal expansion, fastener spacing and edge retention must be checked for the offered panel and existing frame.
Can you quote a clear replacement panel from my drawing?
Yes. Send dimensions, quantity, holes, edge detail, location and performance requirements. SinoPlastix can quote a custom PC option, including an appropriate surface finish. Final price and lead time depend on the confirmed design.