ACRYLITE 16 mm Multi-Skin Greenhouse Panels (Resist and Alltop)
The twin-wall acrylic that commercial growers glaze with: 86 percent light in the standard Resist sheet, 91 percent in the wide-rib Alltop, R-2.04 insulation, a NO DRIP coating, and a non-prorated 30-year non-yellowing warranty. Twice the price of polycarbonate and worth it if you are keeping the greenhouse.
By Sergio Igartua, Founder & Editor · Updated · How we research
Key facts
- Polyvantis makes ACRYLITE 16 mm multi-skin greenhouse panels in two versions, Resist and the wide-rib Alltop.
- ACRYLITE Resist 16 mm clear transmits 86 percent of light; Alltop transmits 89 to 91 percent.
- ACRYLITE 16 mm panels insulate at R-2.04 and carry a non-prorated 30-year non-yellowing warranty.
- Greenhouse Megastore sells ACRYLITE 16 mm panels from $1,225 per 5-panel bundle.
- AcrylicWindow.com rates ACRYLITE 16 mm multi-skin panels 4.7 out of 5 for heated greenhouses kept long term.
Pros
- 86% light transmission (Resist 16 mm) and 89–91% (Alltop 16 mm), against 72–76% for 16 mm polycarbonate
- Non-prorated, full-replacement warranties: 30 years against yellowing, 10 years on light transmission, 10 years on hail
- R-2.04, U-0.49 twin-wall insulation; the maker cites up to 40 percent energy savings over single glazing
- NO DRIP coating spreads condensation into a film instead of drops that scatter light and drip on plants
- UV-stable through the sheet, so a scratch does not expose unprotected plastic
- Stiff: a 47-inch-wide 16 mm sheet needs no cross supports for uniform loads to 15.7 lb per sq ft
Cons
- Roughly double the price of 16 mm polycarbonate, and freight only
- About 1 lb per sq ft, nearly twice polycarbonate's weight; check the frame
- Combustible, ASTM D-635 class CC2, with area limits in some codes
- Moves 1/16 in per foot with heat and moisture; wood battens and screws through the sheet will crack it
- Seasonal stock-outs are routine, and custom lengths under 20 sheets carry a repacking charge
Specifications
| Material | Impact-modified extruded acrylic (PMMA), double-skin |
| Light transmission | Resist 16 mm clear 86% (Light White 74%, Bronze 53%, Solar Cool White 37%); Alltop UV-absorbing 89%, UV-transmitting 91% |
| Insulation | R-2.04, U-0.49 (16 mm); 8 mm is R-1.78, U-0.56 |
| Rib spacing | Resist 16 mm 32 mm (1 1/4 in); Alltop 64 mm (2 1/2 in) |
| Sheet size | 47 1/4 in (1200 mm) wide; Resist to 36 ft, Alltop to 28 ft; retail lengths 6–16 ft |
| Weight | 0.9–1 lb per sq ft (16 mm); 0.7 lb (8 mm) |
| Thermal movement | 6 mm per m (1/16 in per ft) |
| Service temperature | 160°F max without load |
| Fire | ASTM D-635 CC2; CAN/ULC S102.2 flame spread under 150; self-ignition 830°F |
| Sound | 24 dB weighted reduction (16 mm) |
| Support | 16 mm at 1200 mm wide: no cross members to 15.7 lb/sq ft; 8 mm: supports at 106 in |
| Warranty | Non-prorated full replacement: 30 yr non-yellowing (colorless), 10 yr light transmission, 10 yr hail |
| Price | Greenhouse Megastore: 16 mm from $1,225 per 5-panel bundle; 8 mm from $745 |
| Maker | Polyvantis (the Röhm acrylic business), Sanford, Maine and Germany |
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Our Verdict
The glazing to buy for a greenhouse you plan to keep for twenty years and heat through winter. Use the aluminum glazing system made for it, order in late winter, and take the Alltop wide-rib version if light matters more than UV blocking.
Overview
ACRYLITE multi-skin is twin-wall acrylic: two skins of impact-modified acrylic joined by ribs, extruded as one sheet 47 1/4 inches wide and up to 36 feet long. It is the glazing on commercial, research, and institutional greenhouses that chose acrylic over polycarbonate, and it is our Best Overall pick in the greenhouse panel roundup. This review goes deeper into the two 16 mm versions, the published numbers behind them, the warranty that separates them from polycarbonate, and the handling rules that separate a twenty-year roof from a cracked one.
The sheet is made by Polyvantis, the company that took over the Röhm acrylic business; ACRYLITE is the brand in the Americas and PLEXIGLAS everywhere else. It ships from Sanford, Maine and from the plant in Germany. We have not glazed with it. The figures come from the maker's technical sheet and selection chart, a distributor's listing, and university extension data, all listed at the end.
Resist versus Alltop
ACRYLITE Resist is the standard multi-skin: 8 mm with 16 mm ribs, or 16 mm with 32 mm (1 1/4 inch) ribs. Clear 16 mm transmits 86 percent of light; the 8 mm, 84 percent. It is UV-blocking, which is what most growers want, and it comes in Light White (74 percent), Bronze (53), and Solar Cool White (37) for shade and heat control, plus a Clear Diffuse version that scatters light into the canopy.
ACRYLITE Alltop is the same 16 mm sheet with ribs 64 mm (2 1/2 inches) apart, so less rib shadow and more light: 89 percent in the UV-absorbing version and 91 percent in the UV-transmitting one. The UV-transmitting sheet exists for growers who want the full solar spectrum, which the maker says increases growth and quality in certain crops and reduces the need for supplemental UV. Alltop carries the NO DRIP coating on both sides and runs to 28 feet long. Both versions carry the same insulation, R-2.04 and U-0.49.
For comparison, the same distributor's 16 mm triple-wall polycarbonate transmits 76 percent, and the Alltop literature quotes 72 percent for 16 mm polycarbonate. Ten to fifteen points of light is a real difference in a winter greenhouse.
The warranty
This is the argument for acrylic in one paragraph. ACRYLITE's warranties are non-prorated and full replacement: 30 years against yellowing on colorless sheet, 10 years on light transmission, and 10 years on hail. Acrylic is UV-stable as a material rather than by a coating, which is why the maker can promise the sheet will not yellow, go brittle, or lose light, and why a scratch through the surface does not start the degradation that a scratched polycarbonate cap layer does. The University of Arkansas greenhouse program puts acrylic bi-wall at a 20 to 25 year life with minimal light loss over ten years.
NO DRIP and condensation
Every greenhouse sweats. On plain glazing the condensation forms droplets that scatter light and rain on the benches, which is how algae and fungus get started. The patented NO DRIP coating makes water spread into a continuous film that runs to the gutter instead. On Resist it is on one side; on Alltop, both. The coating ships under a protective layer that has to be washed off with water and a sponge, or hosed down, to activate it, and it is the reason to leave the film on until the panel is installed.
Weight, stiffness, and movement
The 16 mm sheet weighs 0.9 to 1 pound per square foot, against about 0.55 for 16 mm polycarbonate. In return it is stiff: supported on all sides at 1200 mm wide, a 16 mm sheet needs no intermediate cross members for uniformly distributed loads up to 15.7 pounds per square foot. The 8 mm needs supports every 106 inches. Fewer purlins means less shadow.
The number that ruins acrylic roofs is 6 mm per metre, or 1/16 inch per foot: how much the sheet moves with heat and moisture. A 16-foot panel grows and shrinks a full inch. The maker's installation guidelines and the aluminum bar-and-gasket systems sold for the sheet allow for it. Screws through the sheet into wood battens do not, and the sheet cracks at the hole. Maximum service temperature is 160°F, so a black-painted bar in full sun is another thing to avoid.
Fire
Acrylic burns. ACRYLITE is rated C2 or CC2 under ASTM D-635, under 150 flame spread on CAN/ULC S102.2, and B2 under DIN 4102, with a self-ignition temperature of 830°F and low smoke. The maker's own precaution sheet says it burns rapidly to completion if not extinguished. Building codes classify it as a CC2 light-transmitting plastic with area limits, and our acrylic vs glass guide explains the classes. Polycarbonate is CC1 and far less flammable, and that is the one argument for it that acrylic cannot answer.
Price and buying
Greenhouse Megastore lists 16 mm clear from $1,225 in five- and ten-panel bundles, 47 1/4 inches wide in lengths from 6 to 16 feet, and 8 mm from $745. Both were sold out when we checked, which is normal in season; order in late winter. Delivery is by motor freight with a truck that needs up to 70 feet of access and someone on site to unload. Custom cut lengths are available to 28 feet, and the Evonik-era catalog listed a $300 repacking charge for custom orders under 20 sheets, with special-order lengths non-returnable.
The polycarbonate on the same shelf starts at $685 a bundle. The premium buys light, a warranty polycarbonate does not offer, and a roof that looks the same in year fifteen.
Who should buy it
Growers and hobbyists who heat through winter, who plan to keep the structure, and whose frame can carry a pound per square foot. Choose Resist if you want UV blocking and a shade color option; choose Alltop if light transmission is the priority. For an unheated house, a roof over a shade structure, or a tighter budget, the corrugated single-skin ACRYLITE panel has the same warranty and 90 percent light with no insulation.
Sources
- Polyvantis: ACRYLITE Resist multi-skin technical information (10/24, PDF) and ACRYLITE Alltop
- Hummert / Evonik: ACRYLITE for greenhouses selection chart (PDF)
- Greenhouse Megastore: ACRYLITE 16 mm clear acrylic panel and acrylic panels collection
- Acrylic Building Products: ACRYLITE Alltop double skin UV transmitting and USGR: acrylic twinwall sheets
- University of Arkansas: Greenhouse glazing materials
Frequently asked questions
How much do ACRYLITE 16 mm multi-skin greenhouse panels cost?
Greenhouse Megastore lists ACRYLITE 16 mm clear multi-skin from $1,225 per five-panel bundle and the 8 mm from $745, in five- and ten-panel bundles 47 1/4 inches wide and 6 to 16 feet long. Polycarbonate on the same shelf starts at $685 a bundle, so the acrylic is roughly double. Delivery is motor freight only, and the Evonik-era catalog listed a $300 repacking charge on custom orders under 20 sheets.
What is the difference between ACRYLITE Resist and ACRYLITE Alltop?
ACRYLITE Resist is the standard multi-skin, 8 or 16 mm with 32 mm rib spacing, 86 percent light transmission in clear 16 mm, UV-blocking, and available in shade colors such as Light White at 74 percent and Bronze at 53. Alltop is the same 16 mm sheet with ribs 64 mm apart, so less rib shadow: 89 percent light in the UV-absorbing version, 91 percent in the UV-transmitting one, with NO DRIP on both sides.
Are ACRYLITE panels better than polycarbonate for a greenhouse?
For light and longevity, ACRYLITE wins. The 16 mm sheet transmits 86 percent against 72 to 76 percent for 16 mm polycarbonate, and acrylic is UV-stable through the sheet, so a scratch does not expose unprotected plastic. The warranties are non-prorated full replacement: 30 years against yellowing, 10 on light transmission, 10 on hail. Polycarbonate wins on fire class, CC1 against CC2, and on weight and price.
What warranty comes with ACRYLITE multi-skin panels?
ACRYLITE multi-skin carries non-prorated, full-replacement warranties: 30 years against yellowing on colorless sheet, 10 years on light transmission, and 10 years on hail. Because acrylic is UV-stable as a material rather than by a surface coating, the maker can promise the sheet will not yellow, go brittle, or lose light. The University of Arkansas greenhouse program puts acrylic bi-wall life at 20 to 25 years with minimal light loss over ten.
How well do ACRYLITE 16 mm panels insulate?
ACRYLITE 16 mm multi-skin is rated R-2.04 and U-0.49; the 8 mm version is R-1.78 and U-0.56, and the maker cites up to 40 percent energy savings over single glazing. Weighted sound reduction is 24 dB at 16 mm. The NO DRIP coating spreads condensation into a film that runs to the gutter rather than dripping on the benches, which is how algae and fungus usually get started.
What goes wrong when installing ACRYLITE multi-skin panels?
Thermal movement is what ruins ACRYLITE roofs. The sheet moves 6 mm per metre, or 1/16 inch per foot, so a 16-foot panel grows and shrinks a full inch, and screws driven through it into wood battens crack it at the hole. Use the aluminum bar-and-gasket glazing system made for the sheet, keep it below the 160°F service limit, and check the frame can carry about a pound per square foot.
Are ACRYLITE 16 mm panels worth the money?
For a greenhouse you plan to keep and heat through winter, ACRYLITE 16 mm is worth roughly double the price of polycarbonate: ten to fifteen points more light, R-2.04 insulation, and a non-prorated 30-year non-yellowing warranty polycarbonate does not offer. For an unheated house, a roof over a shade structure, or a tighter budget, the corrugated single-skin ACRYLITE panel has the same warranty and 90 percent light with no insulation.