Journal · 2026.02 · 7 min

Why Good Greenhouses Use So Much Aluminium — and Why ESG Favours It

Corrosion-free, precision-formable, recyclable almost indefinitely — and one-third the weight of steel. Hwa-Nan cuts its own dies to develop profiles for Taiwan’s climate, making construction faster and safer, and giving greenhouses real numbers to show in the ESG era.

Steel can carry a typhoon, but it can’t carry Taiwan’s moisture. That’s why a good greenhouse isn’t all steel — the precision parts that move every day and rust first, the gutters, vent frames and shade rails, are almost always aluminium. Not fashion, but each material where it serves best.

In a high-spec greenhouse the primary structure is usually hot-dip galvanized steel — but the precision parts, gutters, vent frames, door frames, and shade-screen rails, are almost always extruded aluminium. The reasons are practical: aluminium is light with a high strength-to-weight ratio, its surface forms a dense natural oxide layer that resists corrosion, and extrusion produces complex profiles with tiny tolerances — keeping drainage, venting, and drive mechanisms that cycle hundreds of times a day running smoothly for years.

Aluminium is about one-third the density of steel, and that seemingly simple weight difference translates directly into cost on site. Lighter members are quicker to lift and handle, noticeably cutting the time cranes and heavy machinery spend on the job — on remote farmland or tight sites, that equipment cost is often more significant than the material itself.

Even more important is how it is joined: extruded aluminium members are bolted together, so no hot-work welding is needed on site. With no welding sparks or open flame, there is no risk of igniting flammable materials such as shade screens or poly film — greatly improving on-site safety, while keeping the work cleaner and faster.

Material-flow analysis by the International Aluminium Institute (IAI) shows that of the roughly 1.5 billion tonnes of aluminium produced since 1888, nearly 75% is still in use today. Recycling aluminium takes about 95% less energy than primary production, and the carbon footprint drops from about 15.1 tonnes of CO₂e per tonne for primary metal to about 0.52 tonnes for recycled. Most importantly, aluminium can be recycled again and again without losing quality — at end of life it isn’t waste, but feedstock for the next product.

• Recycled at retirement: when a greenhouse is dismantled, aluminium parts feed straight into a mature recycling stream — high residual value, almost nothing to landfill.
• Demountable and movable: bolted aluminium extrusions can be disassembled and reused on a new site rather than consumed once.
• Longer life: no corrosion means fewer replacements — and less scrap generated.
• No anti-rust coatings: aluminium needs no protective paint, avoiding the environmental load of coatings, solvents, and future flaking.

The growing belongs to the grower; the lifespan and residual value of materials is what the engineering side can look after for you. Hwa-Nan doesn’t buy off-the-shelf aluminium — we cut our own dies and manufacture profiles developed specifically for Taiwan’s tropical and subtropical climate, and design from day one for future demountability and recovery — so the greenhouse is not only more durable, but ready for the next decade of sustainability scrutiny.

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