Glass vs Polycarbonate Greenhouses

Glazing is one of the biggest choices you'll make when buying a greenhouse. It affects how much light your plants get, how warm the greenhouse stays, how safe it is, and how it looks. Here's a straightforward comparison, with the options available on the greenhouses we sell.

At a glance

Glass

Glass gives the clearest view and the most direct light, and it stays clear for the life of the greenhouse. It's easy to clean and looks the part in any garden.

• Horticultural glass is the standard, lower-cost option and fine for most home growing. It's thinner, and if broken it leaves sharp pieces.
• Toughened safety glass is stronger and breaks into small granules rather than shards. It's the one to choose around children and pets.
• Weight: glass is heavy, so it needs a sturdy frame and a firm, level base. See choosing a base.

Polycarbonate

Polycarbonate is a tough, lightweight plastic sheet. Greenhouse polycarbonate is usually twin-wall: two skins with a layer of air between them.

• Very hard to break, which makes it a good choice where balls fly or in a busy family garden.
• Holds heat better than a single pane of glass thanks to the air layer, which helps on cold nights and early in the season.
• Diffused light: it's less clear than glass. It spreads the light, which some growers like, but you won't get a clear view out.
• Care: it can dull over many years in sunlight and scratches more easily than glass. Clean with a soft cloth.
• Light but secure: panels are light, so in an exposed spot make sure they're properly fixed and the greenhouse is anchored to its base.

What's available on our greenhouses

Elite Greenhouses

Most of the everyday Elite range, such as the Compact, Streamline, Craftsman, Vantage, Belmont and Windsor lean-to, comes with a choice of horticultural or toughened safety glass. The Edge 400, Edge 600 and Zenith 800 offer 4mm toughened glass or 6mm twin-wall polycarbonate. The Edge 800 offers 4mm toughened glass with a 6mm polycarbonate roof, or 6mm twin-wall polycarbonate throughout. See our Elite buying guide.

Vitavia

Several Vitavia models give you a choice. The Neptune, Jupiter and Phoenix come in 3mm horticultural glass, 3mm toughened glass or 6mm polycarbonate, and the Venus and Apollo in horticultural glass, toughened glass or 4mm polycarbonate. The Hera and Ida offer mixed options with glass sides and a 6mm polycarbonate roof. The Saturn and Orion are glass only. See our Vitavia buying guide.

Coppice Collection

The timber Coppice Collection greenhouses are glazed in 3mm toughened glass throughout, and they're installed for you.

Which should you choose?

• Keen grower, sheltered garden: glass, toughened if you can.
• Young children, pets or ball games: toughened glass or polycarbonate.
• Exposed, windy site: a sturdy frame with toughened glass or polycarbonate, properly anchored.
• Want to keep plants warmer early and late in the season: twin-wall polycarbonate, or a roof in polycarbonate.
• Traditional look: glass, perhaps in a timber greenhouse.

Not sure what size you need? See what size shed or greenhouse do I need?, or browse all greenhouses.

Common questions

Is glass or polycarbonate better for a greenhouse?

Glass lets in the clearest light, stays clear for life and looks traditional. Twin-wall polycarbonate is lighter, very hard to break and holds heat better, but is less clear. Glass suits growers who want the most light; polycarbonate suits exposed gardens and families with young children.

What's the difference between horticultural and toughened glass?

Horticultural glass is the standard, lower-cost option. Toughened safety glass is stronger, and if it does break it crumbles into small granules rather than sharp shards, so it's the safer choice around children and pets.

Does polycarbonate go cloudy?

Polycarbonate can become less clear over many years in sunlight, and it scratches more easily than glass, so clean it with a soft cloth and mild soapy water.

Is a polycarbonate greenhouse warmer?

Twin-wall polycarbonate traps a layer of air between its two skins, so it holds heat better than a single pane of glass. That helps on cold nights, but ventilation still matters in summer.

Can I have both?

Yes, on some models. For example, the Vitavia Hera is available with toughened glass sides and a 6mm polycarbonate roof, and the Elite Edge 800 with toughened glass and a 6mm polycarbonate roof.

This guide is general information, not professional or legal advice. Specifications vary by model, so always check the product page, and check planning and building regulations with your council.