Acrylic weighs half as much as glass (1.19 vs 2.5 g/cm³), takes 17 times the impact before breaking, and transmits more visible light (92% vs 90–91%) — yet glass still wins on surface hardness, heat resistance and price per square metre in flat standard sizes. The right choice is application-specific, and for fabricated shapes, bonded assemblies and overhead installations the answer is usually acrylic.
Specifiers usually arrive at this comparison from one of two directions: an architect or designer replacing glass because of weight or safety, or a purchasing manager asked why the acrylic quote is higher than the float-glass one. Both deserve straight numbers rather than material evangelism — acrylic is our business, but glass genuinely wins several use cases, and knowing which saves everyone a failed installation.
The Core Numbers
| Property | Acrylic (PMMA) | Glass (float/tempered) | Advantage |
|---|---|---|---|
| Density | 1.19 g/cm³ | 2.5 g/cm³ | Acrylic — 52% lighter, smaller substructure, safer overhead |
| Impact resistance | ~17× float glass | Baseline (tempered ≈ 4× float) | Acrylic — and it fails blunt, not in shards |
| Light transmission (3 mm, visible) | 92% | 90–91% (green edge tint in thick sections) | Acrylic, especially in thick blocks — no green cast |
| Surface hardness | Scratches under abrasive cleaning | Highly scratch-resistant | Glass — decisive for horizontal wear surfaces |
| Continuous service temperature | ~80 °C | 250 °C+ (tempered) | Glass — heat lamps, fireplaces, hot process |
| Fabrication freedom | CNC machining, laser cutting, thermoforming, seamless bonding | Cut/drill before tempering only; no re-work after | Acrylic — this is where most conversions happen |
| UV / weathering | Excellent — no yellowing for 10+ years outdoors | Excellent | Tie — acrylic is the only clear plastic that matches glass here |
| Price, flat standard sheet | Higher per m² | Lower per m² at commodity sizes | Glass — for plain rectangles, glass is hard to beat |
| Installed cost, shaped or overhead work | Often lower | Rises fast: handling weight, tempering, breakage rate | Acrylic — the fair comparison is installed, not per-sheet |
Where Acrylic Is the Right Specification
- Display cases and retail fixtures. Solvent-polished, seamlessly bonded five-sided cases have no gaskets, no metal frame and no visible joint — a construction glass physically cannot replicate. Half the weight also means display furniture that staff can actually move.
- Overhead and suspended installations. Ceiling features, canopies and suspended architectural elements carry a simple argument: half the dead load and no shard-fall failure mode. Building reviewers accept overhead acrylic where overhead glass triggers laminated-glass requirements.
- Curved and formed geometry. Thermoformed domes, radiused corners and line-bent returns come off standard tooling in acrylic; curved tempered glass is a specialist product with weeks of lead time and high minimums.
- Anywhere people collide with the panel. Hospitality partitions, balustrade infills, guest-facing features, sports viewing windows: acrylic’s failure mode (crack, stay in frame) is the safety argument, independent of its strength numbers.
- Thick transparent sections. Above ~15 mm, glass goes green and gets extraordinarily heavy; acrylic blocks stay water-clear at 100 mm+ — the reason aquariums and museum vitrines converted decades ago.
Where Glass Is Honestly Better
- Horizontal wear surfaces. Countertops, table tops and shelf surfaces that get wiped daily with whatever cleaner is at hand: glass shrugs off the abrasion and the ammonia; acrylic will haze without disciplined cleaning.
- Heat. Fireplace screens, food warmer sneeze guards over heat lamps, anything above ~70 °C continuous — acrylic is the wrong polymer, and usually the wrong material class.
- Fire-rated assemblies. Where the specification calls for a fire-resistance rating, acrylic (a combustible plastic) does not play; fire-rated glazing does.
- Commodity flat rectangles. Standard-size vertical windows in frames, no shaping, no safety driver: float or tempered glass will beat acrylic on unit price and scratch life.
The Cost Comparison Buyers Actually Need
Per-square-metre sheet price is the wrong number to compare. The installed comparison has four lines that consistently move the total toward acrylic on fabricated work: substructure (half the panel weight → lighter framing and fixings), handling (two installers instead of four plus a vacuum lifter above ~2 m² panels), breakage (transit and site breakage on tempered glass is a real budget line; acrylic transit damage is rare and repairable), and rework (a mis-drilled tempered panel is scrap; acrylic can be re-machined). On plain framed rectangles none of these apply — which is exactly why glass keeps that territory.
One more decision layer: if you have already ruled out glass and are choosing between plastics, impact-critical applications may point to polycarbonate instead — that comparison is in our acrylic vs polycarbonate guide.
FAQ
Q: Is acrylic cheaper than glass? A: Per flat square metre in standard sizes, no — float glass is usually cheaper. Installed on fabricated, curved, bonded or overhead work, acrylic is frequently cheaper once substructure, handling, tempering and breakage are counted. Compare installed cost, not sheet price.
Q: Does acrylic yellow outdoors compared to glass? A: Quality cast or extruded acrylic with UV stabilisation holds optical clarity 10+ years outdoors — it is the only transparent plastic whose weathering genuinely rivals glass. Yellowing stories almost always trace to cheap recycled-content sheet or to polycarbonate without a UV cap layer.
Q: Is acrylic safe to use overhead instead of glass? A: That is one of its strongest cases: 52% less dead weight and a failure mode that cracks in place rather than dropping shards. Suspended acrylic features and canopies are routine; overhead glass typically has to be laminated to be acceptable.
Q: How much lighter is acrylic than glass for the same panel? A: Acrylic is 1.19 g/cm³ against glass at 2.5 g/cm³ — a 2 m² panel at 10 mm weighs about 24 kg in acrylic versus 50 kg in glass. That difference cascades into framing, fixings, freight and installer count.
Converting a glass detail to acrylic?
Send the drawing or even a photo of the glass original — we confirm whether acrylic is the right call (and say so if it is not), then quote the fabricated panels within 12 hours.