By Mark Wu, Co-founder & Technical Director, Sichuan Zhifang Net Industry Co., Ltd.
A black shade net and an aluminized screen can both be rated at 70%. Put them over two identical houses on the same afternoon and the house under the reflective screen runs cooler — typically 3 to 5 °C cooler under the net.
That gap is not marketing. It comes from what each material does with the light it does not transmit.
A black net absorbs the solar energy it blocks. The energy does not vanish; it turns into heat on the fabric surface, and that heat sits directly above the crop. An aluminium film reflects the energy back toward the sky before it is ever converted to heat inside the structure. Same shading figure, two different energy paths, and the difference ends up in the air the plants are breathing.
For growers in hot, high-irradiance regions — West Africa, the Gulf, South Asia, northern Australia — this is the single largest lever on summer house temperature that does not require electricity.
The feedback is strongest when the screen faces a bright sky, which is exactly when the crop is under stress.
| Time of day | Black shade net | Aluminized reflective screen |
|---|---|---|
| Peak sun (11:00–15:00) | Absorbs and re-radiates heat into the house | Reflects a large share of incoming energy back to the sky |
| Afternoon, high air temperature | Net itself becomes a warm surface above the canopy | Surface stays closer to air temperature |
| Night, closed house | Little to no thermal benefit | Reflects heat emitted by the crop and soil back down, slowing overnight heat loss |
| Cloudy day | Blocks light with little cooling benefit | Still reflects, but the benefit narrows |
That last row matters for specification. A reflective screen earns its cost on sunny, high-load sites. On a heavily overcast site, the return is much smaller and a standard knitted net is the better buy.
Here is the part buyers outside the greenhouse industry rarely expect. An aluminized screen works in both directions.
During the day, the aluminium face reflects solar energy outward and keeps the house cooler. At night, the same face reflects the long-wave heat radiated upward by the crop and soil back down into the house, so the structure loses heat more slowly and the temperature holds steadier until morning.
For growers in high-altitude or desert environments with cold nights and hot days, that dual behaviour is worth more than the daytime cooling alone. A house that swings 20 °C between day and night stresses the crop more than one that swings 10 °C, even when the daytime peak is similar.
That night-time performance is the design purpose of our aluminium foil thermal retention screen for greenhouse night use.
Aluminized screens carry two numbers rather than one, and both belong in the quotation.
Shade rate is the fraction of light blocked. Energy-saving rate is the fraction of heat retained — a different measurement, and it is always higher than the shade rate at the same specification. Our energy-saving range, for example, runs from 55% shading at 57% energy saving up to 99% shading at 82% energy saving. If a supplier quotes you a single figure and calls it "cooling performance", you are not comparing like with like.
Look for the shrinkage rate as well. These screens are tensioned on a drive system inside the house, and a material that shrinks in service pulls away from its fixings and opens gaps. We hold our screens to a stated 1% shrinkage rate, which is a controlled figure rather than a description.
And check the structure. Our reflective shading series is woven from aluminium film and polyethylene strips with no bare gaps between the film — the film is continuous through the weave, so the reflection is not interrupted across the panel. You can see the construction close up in our aluminium shade net for greenhouse cooling.
Reflective screens fail differently from black net, and both failure routes show up in the quotation before you buy.
Film separation. Low-cost aluminized screen uses a thin metallised layer that can delaminate from the carrier as the material flexes on the drive system. Once the film lifts, the reflective performance drops away in patches and the screen looks mottled within a season or two. A properly bonded film survives the repeated folding the screen goes through every day.
UV degradation of the carrier. The aluminium reflects most of the load, but the polymer yarn still needs its own stabilizer package, because gaps and edges take direct exposure. This is where the kly guarantee applies. We build our screens from new imported and domestic raw materials with UV and anti-ageing formulas and cite a 500kly guarantee on the range, rather than relying on the aluminium alone to carry the material.
A note from field history that is worth keeping in mind: one of our projects was a ten-hectare desert farm in Saudi Arabia supplied in 2019 with aluminium foil shade net. In that extreme UV environment the screen held its structure and reflective face over long service. Adequate UV stabilizer in virgin material is what makes that outcome possible, and it is the first thing a low-cost alternative removes.
It is not for every site, and we say so rather than sell it to everyone.
It pays for itself on high-value crops where a temperature spike directly costs yield — protected vegetables, floriculture, orchids, nursery stock, and any operation already paying for cooling.
It pays for itself where nights are cold and days are hot and the crop suffers from the swing.
It pays less on overcast sites, on low-value field-scale crops, and on short-season operations where the screen will not be in service long enough to return the difference.
To compare quotations honestly, ask each supplier for four things: the shade rate, the energy-saving rate, the shrinkage rate, and the UV guarantee in kly. A supplier who can give all four has engineering behind the product. A supplier who returns only a shade percentage and a price has given you the same information as a photo.
Before you accept a roll, check the mark. Every screen we ship carries a ZF label inside the packaging, and it matters here more than in most product families, because reflective screen is exactly the type of material that gets bought in plain form and re-labelled by traders. If the finish and the numbers do not match the price, the label is the one thing on the roll that tells you who actually made it.
If a reflective screen is not the right answer for your site, it is usually lower cost to solve with a standard knitted net. Our full shade net grades are listed in the shade net category.
Send us your site latitude, your coldest and hottest month, and your crop. Our technical team will tell you whether a reflective screen or a standard knitted net is the right specification for that house — including when the answer is the lower-cost one.
Mark Wu, Co-founder & Technical Director
Sichuan Zhifang Net Industry Co., Ltd. — Sichuan, China
sales6@cnshadenet.com ｜ +86 177 8077 1810 (WhatsApp)
