Choosing the right transparent material for your project affects everything from installation ease to long-term maintenance costs. Glass has served as the traditional choice for centuries, but modern plastics like acrylic and polycarbonate now offer compelling alternatives. This guide helps you understand when each material makes sense for your specific application.
The decision isn’t simply about finding the “best” material. Each option excels in different situations. Glass offers superior scratch resistance. Acrylic provides the best optical clarity. Polycarbonate delivers unmatched impact strength. Your project requirements determine which characteristics matter most.
We’ve compared these materials across the factors that actually affect your project: strength, weight, clarity, cost, workability and maintenance. You’ll find practical recommendations for specific applications, helping you match materials to real-world needs rather than making decisions based on incomplete information.
Quick Comparison Overview
Understanding the fundamental differences helps narrow your choice quickly. This table summarises key characteristics:
| Property | Acrylic | Glass | Polycarbonate |
|---|---|---|---|
| Impact Resistance | 17x stronger than glass | Baseline (1x) | 250x stronger than glass |
| Weight | 50% lighter than glass | Heaviest | 40% lighter than glass |
| Light Transmission | 92% (excellent) | 80-90% (good) | 85% (very good) |
| Scratch Resistance | Moderate (can be coated) | Excellent | Poor (easily scratched) |
| UV Resistance | Excellent (with treatment) | Naturally resistant | Good (requires coating) |
| Yellowing Over Time | Minimal (with UV treatment) | None | Moderate (even with coating) |
| Workability | Easy (DIY-friendly) | Difficult (needs specialist) | Moderate |
| Typical Cost | Medium | Low to medium | Medium to high |
| Lifespan (outdoor) | 20-30 years | Indefinite (if unbroken) | 10-15 years |
| Thermal Insulation | Good (20% better than glass) | Poor | Excellent |
This overview shows that no single material dominates across all categories. Your decision depends on which properties your project prioritises.
Acrylic (Perspex) Detailed Breakdown
Acrylic represents the middle ground between glass and polycarbonate, offering a balanced set of properties that suit a wide range of applications.
What Is Acrylic?
Acrylic is a synthetic polymer with the chemical name polymethyl methacrylate (PMMA). You’ll often hear it called by brand names like Perspex in the UK or Plexiglass in the US. These names all refer to the same base material, though quality varies between manufacturers.
Two manufacturing methods produce acrylic sheets with different characteristics. Cast acrylic is poured into moulds and cured slowly, creating superior optical clarity and a harder surface. Extruded acrylic is produced by pushing heated acrylic through rollers, making it more affordable but slightly softer. For most applications, extruded acrylic performs excellently.
Key Strengths of Acrylic
Impact resistance sits between glass and polycarbonate. Acrylic withstands roughly 17 times more impact than standard glass before breaking. When it does fail, it cracks into large pieces with relatively dull edges rather than shattering into dangerous shards. This makes it significantly safer than glass for most applications.
Light transmission reaches 92% for quality acrylic, actually exceeding glass performance. This superior clarity means plants grow as well under acrylic greenhouse glazing as they would under glass. Picture frames using acrylic show artwork more vividly than glass frames. The material maintains this clarity regardless of thickness, whereas thick glass develops a noticeable green tint.
Weight reduction of approximately 50% compared to glass simplifies every aspect of a project. Transport costs decrease. Installation becomes easier, often manageable by one person rather than requiring two. Structural requirements reduce because the glazing weighs less. For furniture, lighter weight reduces stress on joints and supports.
Ease of fabrication distinguishes acrylic from both glass and polycarbonate. Standard woodworking tools cut acrylic cleanly. Home drill bits work fine with proper technique. The material can be heat-formed into curves using basic equipment. This DIY-friendly characteristic makes acrylic accessible for projects that would otherwise require professional fabrication.
UV resistance is available through stabilised formulations. Untreated acrylic will yellow when exposed to outdoor sunlight. UV-stabilised acrylic resists yellowing for 20-30 years, making it suitable for external applications. The UV treatment costs 10-20% extra but is essential for outdoor use.
Weather resistance means acrylic withstands rain, wind and temperature changes without degradation. It doesn’t rust like metal, rot like wood or corrode like some plastics. The material maintains its properties across temperature ranges from -40°C to +80°C, covering all conditions encountered in the UK.
Limitations of Acrylic
Scratch susceptibility is acrylic’s main weakness compared to glass. The surface scratches more easily under abrasion. This matters for applications involving frequent contact or cleaning. However, hard-coat treatments significantly improve scratch resistance, and minor scratches can be polished out.
Chemical sensitivity means certain cleaning products damage acrylic. Window cleaners containing ammonia cause crazing (fine surface cracks). Solvents like acetone dissolve acrylic. This requires using only mild soap and water or specialist acrylic cleaners. The restriction isn’t onerous but does require awareness.
Higher upfront cost than basic glass for simple applications. A sheet of 3mm acrylic costs more than equivalent glass from a builders’ merchant. However, this comparison ignores fabrication and installation costs. Acrylic’s ease of working often makes the total project cost lower despite higher material cost.
Yellowing without UV protection limits the lifespan of untreated acrylic outdoors. Budget acrylic sheets sold without UV stabilisation might yellow within 5 years of outdoor exposure. This isn’t a limitation of acrylic itself but of choosing the wrong grade for your application.
Lower heat resistance than glass means acrylic isn’t suitable for applications involving high temperatures. It begins softening around 160°C. Don’t use acrylic near open flames, hot stovetops or other heat sources. For most normal applications, this limitation doesn’t matter.
Best Uses for Acrylic
Greenhouse glazing takes advantage of acrylic’s high light transmission, impact resistance and insulation properties. Plants receive maximum light while being protected from storm damage. The material won’t shatter if a flowerpot falls against it or hail strikes during bad weather.
Picture framing benefits from acrylic’s light weight and safety profile. Large frames are much easier to hang using acrylic rather than glass. UV-resistant acrylic actively protects valuable artwork from fading. In homes with children, shatter-resistant acrylic eliminates the danger of glass shards if frames fall.
DIY projects of all kinds suit acrylic’s workability. Secondary glazing, furniture, protective screens and creative projects become achievable with basic tools. The material forgives minor mistakes more readily than glass.
Shop displays and retail fixtures use acrylic extensively. Point-of-sale displays, product showcases and information holders all benefit from clarity and light weight. Retailers can easily modify or rearrange acrylic fixtures.
Secondary glazing improves thermal performance of existing windows without the expense of replacement. Acrylic’s light weight simplifies installation over glass alternatives. The insulation properties are actually superior to single-glazing glass.
Safety applications where shatter-resistance matters include protective screens, barriers and glazing in high-traffic areas. The material provides protection without the danger of glass shards if something goes wrong.
Glass Detailed Breakdown
Glass remains relevant for many applications despite the availability of modern alternatives. Understanding its strengths and limitations helps you decide when it’s the right choice.
What Is Glass?
Glass is a mineral material made primarily from silica sand, heated to extremely high temperatures and cooled rapidly. This ancient material has served humanity for thousands of years. Standard glass (also called annealed or float glass) breaks into large, sharp shards. Tempered glass is heat-treated for increased strength and breaks into small, less dangerous pieces.
Key Strengths of Glass
Scratch resistance is glass’s standout advantage. The hard surface resists scratching from normal contact, cleaning and weathering. You can clean glass with standard window cleaners and paper towels without concern. Over decades, glass maintains its surface quality while acrylic would accumulate fine scratches from the same treatment.
Natural UV resistance means glass blocks most UV radiation without special treatment. This protects furnishings, artwork and materials from sun damage. For picture framing valuable artwork, glass provides this protection inherently while acrylic requires UV-treated versions.
Easy maintenance using standard cleaning products makes glass convenient. Spray-on window cleaners, vinegar solutions and regular household products all work fine. There are no special requirements or products needed.
Heat resistance allows glass to withstand high temperatures that would damage acrylic or polycarbonate. Glass suits applications near heat sources, in direct sunlight where heat buildup occurs, or anywhere high temperatures are possible.
Lower upfront cost for basic applications makes glass economical when you need simple rectangular panels in standard sizes. Builders’ merchants stock common glass sizes at competitive prices. For straightforward glazing without fabrication, glass costs less than acrylic.
No yellowing means glass maintains perfect clarity indefinitely. While acrylic can yellow without UV treatment and polycarbonate yellows even with treatment, glass never changes colour or clarity regardless of exposure.
Traditional aesthetic appeals in period properties and applications where modern materials would look out of place. Glass provides an authentic appearance that plastics can’t quite replicate.
Limitations of Glass
Weight makes glass cumbersome to transport, handle and install. Large panels require two people to manage safely. The weight also increases structural requirements for frames and supports. Transport costs more due to weight and fragility.
Shattering creates dangerous shards with sharp edges capable of causing serious injury. Tempered glass shatters into smaller pieces but still creates a dangerous situation. In homes with children or high-traffic public areas, this safety concern is significant.
Low impact resistance means glass breaks relatively easily from knocks, impacts and flexing. A flowerpot falling against glass glazing will likely smash it. Hailstones can break glass. Accidental impacts from furniture or equipment cause breakage.
Difficult fabrication requires specialist equipment and skills. Cutting glass needs glass-cutting tools and experience. Drilling glass is challenging and risks cracking. Most DIY enthusiasts can’t fabricate glass themselves, requiring professional services that add cost and delay.
Not suitable for DIY work in most cases. The specialist skills and tools required put glass beyond typical DIY capabilities. This increases project costs because you’re paying for professional fabrication and installation.
Higher installation costs offset the lower material cost. Professional installation typically charges more for glass due to the weight, handling difficulty and breakage risk during installation.
Best Uses for Glass
Windows in traditional applications where replacement of existing glass with the same material maintains authenticity and avoids aesthetic issues. Standard window sizes available from glaziers are competitively priced.
Decorative applications where scratch resistance over decades justifies choosing glass. Display cabinets with frequently opened doors benefit from glass’s resistance to handling wear.
High-end picture framing where budget allows premium materials and scratch resistance over many years justifies the extra weight and cost. Museum-quality framing typically uses glass with UV-protective coatings.
Applications where scratch resistance is the priority and safety concerns are minimal. Situations where the glazing isn’t at risk of impact but will be frequently cleaned or handled.
Polycarbonate Detailed Breakdown
Polycarbonate occupies the high-performance end of the clear materials spectrum, offering extreme impact resistance at the cost of other properties.
What Is Polycarbonate?
Polycarbonate is a thermoplastic polymer, chemically different from acrylic despite similar appearance. Common brand names include Lexan and Makrolon. The material was originally developed for extreme-performance applications like bulletproof glazing and aircraft components.
Key Strengths of Polycarbonate
Extreme impact resistance defines polycarbonate. It’s approximately 250 times more impact-resistant than glass, far exceeding acrylic’s already impressive strength. Polycarbonate is virtually unbreakable under normal circumstances. This makes it the material of choice for security applications and high-hazard environments.
Lightweight at about 40% lighter than glass, polycarbonate rivals acrylic for weight reduction benefits. Transport, handling and installation are all easier than glass, though polycarbonate is slightly heavier than acrylic.
Excellent insulation properties exceed both glass and acrylic. Multi-wall polycarbonate sheets with air gaps provide particularly good thermal insulation, making them popular for conservatory roofing and applications where heat retention matters.
Flame-retardant options are available for applications with fire safety requirements. Some polycarbonate formulations are self-extinguishing and produce minimal smoke during combustion. These grades meet stringent fire safety standards.
Temperature tolerance is good, withstanding ranges from -40°C to +120°C. This broader range than acrylic suits applications with extreme temperature conditions.
Limitations of Polycarbonate
Lower optical clarity compared to both acrylic and glass is polycarbonate’s significant drawback. Light transmission typically reaches 85% versus 92% for acrylic. The material also has a slight haze that acrylic and glass lack. This makes polycarbonate less suitable where pristine clarity matters.
Scratches extremely easily, worse than acrylic. The soft surface marks from cleaning cloths, wind-blown debris and normal handling. Hard-coat treatments improve this but don’t achieve the scratch resistance of acrylic, let alone glass.
Yellowing occurs even with UV coating, though stabilised versions minimise this. Expect noticeable yellowing after 10-15 years outdoors even with UV protection. This progressive loss of clarity means polycarbonate has a shorter aesthetic lifespan than UV-stabilised acrylic.
More expensive than acrylic for equivalent thickness. The premium over acrylic can reach 30-50%, justified only when polycarbonate’s unique properties are actually needed.
Limited colour options compared to acrylic. While clear polycarbonate is readily available, the range of colours and tints is narrower. This matters less for functional applications but limits design options.
Bends more under load due to its flexibility. While this flexibility contributes to impact resistance, it means polycarbonate requires thicker sheets than acrylic for equivalent rigidity. A shelf that would work in 8mm acrylic might need 10mm polycarbonate to avoid visible flex.
Best Uses for Polycarbonate
Security applications where break-in resistance is paramount. Polycarbonate glazing in vulnerable areas deters vandalism and forced entry. Banks, jewellers and high-security buildings use polycarbonate extensively.
Machine guards protecting operators from flying debris or component failure. The extreme impact resistance protects against hazards where acrylic would be marginal and glass would be inadequate.
Severe weather locations exposed to extreme conditions benefit from polycarbonate’s toughness. Coastal areas with storm-driven debris, locations prone to hail, or exposed positions suit polycarbonate.
High-impact environments like sports facilities, schools and public areas where vandalism or accidental damage is likely. The material withstands abuse that would destroy glass or damage acrylic.
Safety shields in industrial environments where impact hazards exist. Polycarbonate provides maximum protection while maintaining visibility of processes.
Head-to-Head Comparisons
Real-world decisions often come down to choosing between two materials for a specific application. These direct comparisons address common scenarios.
Acrylic vs Glass for Greenhouse Glazing
Light transmission favours acrylic at 92% versus glass at 80-90%. That extra light translates directly to better plant growth, particularly important during short winter days when every photon counts.
Insulation properties give acrylic a significant advantage. Acrylic provides approximately 20% better thermal insulation than single-pane glass. This reduces heating costs in heated greenhouses and helps maintain stable temperatures in unheated structures.
Durability in weather strongly favours acrylic. Hailstones that would shatter glass bounce off acrylic. Strong winds create less stress on greenhouse frames with lighter acrylic panels. You won’t lose an entire greenhouse roof to storm damage.
Long-term cost analysis shows acrylic winning despite higher upfront cost. Glass panels break and need replacement. Acrylic lasts 20-30 years without breakage. Include expected replacement costs and acrylic proves more economical over the greenhouse’s lifetime.
Recommendation: Acrylic wins for most greenhouses. Choose UV-stabilised acrylic in 4-6mm thickness for hobby greenhouses. The only exception is very large commercial greenhouses where glass is professionally installed and professionally maintained.
Acrylic vs Glass for Picture Frames
Clarity comparison slightly favours acrylic for most situations. The 92% light transmission shows artwork more vividly than glass’s 80-90%. However, premium low-iron glass achieves comparable clarity at significantly higher cost.
UV protection needs depend on artwork value. Standard glass offers basic UV protection. Standard acrylic offers none unless UV-treated. For valuable artwork requiring maximum UV protection, specifically buy UV-resistant acrylic or UV-protective glass.
Weight and hanging considerations make acrylic much easier for large frames. A metre-square frame using 3mm acrylic weighs roughly half what it would with glass. For frames above 50cm x 70cm, acrylic’s weight advantage becomes significant for hanging and wall stress.
Safety in homes with children gives acrylic a decisive advantage. Acrylic won’t shatter if frames fall or are knocked. In family homes, nurseries or children’s rooms, shatter-resistant acrylic provides peace of mind.
Recommendation: Depends on artwork value and situation. For valuable artwork requiring maximum UV protection and scratch resistance over decades, invest in UV-protective glass. For most home framing, especially larger frames or homes with children, UV-resistant acrylic offers better overall value and safety.
Acrylic vs Polycarbonate for Outdoor Use
Clarity over time decisively favours acrylic. UV-stabilised acrylic maintains clarity for 20-30 years. Polycarbonate yellows noticeably within 10-15 years even with UV coating. If maintaining pristine appearance matters, acrylic is the clear choice.
Weather resistance gives polycarbonate an edge in extreme conditions. Very exposed positions, coastal areas or locations prone to impact damage suit polycarbonate’s extreme toughness. For typical UK conditions, acrylic’s weather resistance is more than adequate.
Maintenance requirements favour acrylic slightly. Both scratch easier than glass, but acrylic scratches can be polished out while polycarbonate scratches are permanent. Acrylic maintains better appearance with normal care.
Lifespan expectations show acrylic lasting longer before needing replacement. Plan for 20-30 years with acrylic versus 10-15 years with polycarbonate before yellowing necessitates replacement. This affects long-term cost calculations.
Recommendation: Acrylic for clarity and longevity in normal outdoor applications. Choose polycarbonate only where extreme impact resistance is genuinely necessary, such as vandal-prone areas, severe weather zones or security applications. The clarity sacrifice and yellowing aren’t worth it for normal situations.
Cast Acrylic vs Extruded Acrylic
Production method differences affect properties. Cast acrylic is poured into moulds and cured slowly. Extruded acrylic is pushed through rollers. The slower cast process creates superior optical quality and material properties.
Clarity and quality favour cast acrylic. It achieves the highest optical clarity and most consistent thickness. The harder surface resists scratching better than extruded acrylic. For critical display applications, cast acrylic justifies its premium.
Price comparison shows cast acrylic costing 20-40% more than extruded. For projects requiring multiple sheets, this premium adds up quickly. The question becomes whether the benefits justify the extra cost for your application.
When to choose each: Use extruded acrylic for general applications where good clarity suffices. This includes most greenhouse glazing, DIY projects, protective screens and general fabrication. Choose cast acrylic where optical perfection matters: high-end display cases, museum exhibits, point-of-sale displays for premium products, or anywhere the acrylic itself is a design feature.
Recommendation: Extruded acrylic for 80-90% of applications. The good optical quality and lower cost make it the practical choice. Reserve cast acrylic for applications where clients will notice and appreciate the difference, or where you’re personally invested in achieving the absolute best result.
Making Your Decision: Use Case Guide
Different applications prioritise different properties. These recommendations guide your choice for common projects.
For DIY Home Projects
Recommended material: Acrylic in most situations.
Cost considerations: The moderate upfront cost is offset by DIY installation savings. You can cut and fit acrylic yourself using basic tools, saving professional fabrication and installation costs that glass would require.
Ease of working makes acrylic the DIY-friendly choice. Standard woodworking tools cut it. Drilling requires only basic technique. Mistakes aren’t as catastrophic as with glass. The learning curve is manageable.
Projects like greenhouse glazing, secondary glazing, picture frames and furniture all suit acrylic well. The combination of reasonable cost, ease of working and good properties makes it the default choice for DIY enthusiasts.
For Trade and Professional Applications
Recommended material: Depends on client requirements and application.
Durability requirements often favour acrylic for most installations. The impact resistance and weather resistance suit commercial environments. For security applications, step up to polycarbonate.
Client expectations matter in professional work. Some clients specifically want glass for aesthetic reasons or traditional preferences. Others prioritise safety and choose acrylic. Discuss options with clients to understand their priorities.
Return on investment analysis should include maintenance and replacement costs. Acrylic’s durability means fewer call-backs for broken glass. This matters for your reputation and long-term client relationships.
For retail fixtures, shop fronts and commercial glazing, acrylic typically proves most cost-effective. For security-critical applications, polycarbonate justifies its premium. For heritage properties or specific client requirements, glass remains appropriate.
For Greenhouse and Garden Buildings
Recommended material: Acrylic with UV stabilisation.
Climate considerations in the UK suit acrylic well. The weather isn’t extreme enough to justify polycarbonate’s premium. Glass breaks too easily from storm damage and accidents.
Longevity vs cost analysis shows acrylic winning. UV-stabilised acrylic lasts 20-30 years without yellowing or significant degradation. That’s longer than many greenhouses themselves last. The one-time higher cost spreads over decades of use.
Maintenance factor keeps acrylic ahead. You won’t replace broken panes. Cleaning requires only soap and water. The material tolerates the conditions plants require – high humidity, temperature fluctuations and occasional knocks from gardening activities.
Twin-wall acrylic sheets offer enhanced insulation for heated greenhouses or cold climates. Single-sheet acrylic works fine for most hobby greenhouses in the UK.
For Safety and Security Applications
Recommended material: Polycarbonate for extreme security needs; acrylic for general safety applications.
Impact requirements determine the choice. General impact protection (protecting against accidental damage) suits acrylic. Deliberate attack resistance or extreme hazard protection requires polycarbonate.
Regulatory compliance might specify minimum impact resistance. Check whether your application has specific requirements. Machine guards, for instance, often specify minimum impact standards that determine material choice.
Insurance considerations sometimes require particular materials. Security applications protecting valuable goods might need polycarbonate to satisfy insurance requirements. Check your policy requirements before specifying materials.
For protective screens, reception barriers and general safety glazing, acrylic provides adequate protection at lower cost. For bank counters, jeweller displays and high-security areas, polycarbonate’s extreme toughness justifies its premium and clarity sacrifice.
Common Misconceptions
Clearing up confusion helps you make informed decisions.
“Perspex and acrylic are different materials” – FALSE
Perspex is simply a brand name for acrylic, like Hoover is a brand of vacuum cleaner. All Perspex is acrylic. Not all acrylic is branded Perspex. The terms are interchangeable. Quality differences exist between manufacturers, but that’s true of any material.
“Glass is always clearer than acrylic” – FALSE
Quality acrylic transmits 92% of visible light while standard glass transmits 80-90%. Acrylic is actually clearer. Very thick glass shows a green tint completely absent in acrylic. The perception that glass is clearer probably comes from comparing new glass to old, scratched acrylic.
“Polycarbonate never yellows” – FALSE
Even UV-stabilised polycarbonate yellows over time. It yellows less and more slowly than untreated polycarbonate, but yellowing still occurs. Expect noticeable colour change after 10-15 years outdoors. UV-stabilised acrylic, by contrast, maintains clarity for 20-30 years.
“Acrylic can’t be used outdoors” – FALSE
UV-stabilised acrylic performs excellently outdoors for 20-30 years. The misconception probably stems from seeing failed cheap acrylic that lacked UV stabilisation. Choose the correct grade and acrylic suits outdoor applications perfectly.
“Glass is always stronger” – FALSE
Glass is stronger in compression but much weaker in impact. Acrylic withstands 17 times more impact than glass. Polycarbonate is 250 times stronger against impact. Glass’s brittleness makes it the weakest option for most real-world situations.
Quick Decision Flowchart
Start here: What matters most for your project?
→ Maximum clarity and appearance: Does budget allow cast acrylic’s premium?
- Yes → Cast acrylic
- No → Extruded acrylic
→ Extreme impact resistance: Is security/protection the priority?
- Yes → Polycarbonate
- No → Continue
→ Scratch resistance over decades: Can you tolerate glass’s weight and breakage risk?
- Yes → Tempered glass
- No → Hard-coated acrylic
→ Budget is primary concern: Can you install yourself?
- Yes → Extruded acrylic (best value)
- No → Glass (if simple shape) or acrylic (if custom)
→ Traditional aesthetic essential: Period property or client preference?
- Yes → Glass
- No → Acrylic offers better performance
→ Outdoor application: UV exposure significant?
- Yes → UV-stabilised acrylic or tempered glass
- No → Standard acrylic or glass fine
This simplified flowchart covers most common decisions. Complex requirements might need professional consultation, but these guidelines point you toward the right material for typical projects.
Conclusion
No single material wins across all applications. Each option brings different strengths to different situations.
Acrylic suits most general applications with its balanced properties: good clarity, reasonable impact resistance, light weight and DIY-friendly fabrication. It’s the default choice for greenhouses, picture frames, displays and DIY projects.
Glass remains appropriate where scratch resistance over decades justifies accepting greater weight and breakage risk. Traditional applications, heritage properties and situations where professional installation is already planned might favour glass.
Polycarbonate serves niche applications requiring extreme impact resistance where clarity can be sacrificed. Security glazing, machine guards and vandal-resistant installations justify polycarbonate’s premium despite its limitations.
For most readers of this guide, UV-stabilised extruded acrylic in appropriate thickness provides the best combination of performance, cost and ease of use. It delivers 80-90% of polycarbonate’s impact resistance at 60% of the cost. It offers glass-exceeding clarity at half the weight. It enables DIY fabrication that glass doesn’t allow.
Make your decision based on your specific priorities. Identify your top three requirements from this list: clarity, impact resistance, scratch resistance, cost, weight, workability, lifespan. Choose the material that best satisfies those priorities. Don’t try to optimise everything – focus on what actually matters for your project.
Ready to start your project? Our UV-stabilised clear acrylic sheets are available in all thicknesses from 2mm to 30mm, with custom cutting services available to save you time and ensure perfect fit.