i2 Coating & i2 Film Passive Radiative Cooling

i2Cool is a spin-off from the School of Energy and Environment at City University of Hong Kong. Its research began in 2016, inspired by the hair structure of the Saharan silver ant, and i2Cool (Hong Kong) was established in June 2021, followed by a Shenzhen subsidiary and a joint-venture factory in Guangzhou. The company addresses heat gain on roofs, walls and outdoor equipment, which drives air-conditioning load and equipment failures in hot climates.

Its products use passive radiative cooling: a micro- and nano-structured surface reflects sunlight and emits heat to outer space through the 8-13 micrometre atmospheric window without using electricity. The range covers i2 Coating paints for buildings, power and telecom cabinets, logistics, grain storage, photovoltaic and chemical plants, i2 Film window and membrane films, powders, masterbatches, ceramics and textiles. Customers include property developers, utilities, telecom operators and industrial owners.

• i2 Coating: radiative cooling paint for roofs, walls, tanks and outdoor equipment.
• Sector variants: formulations for power and telecom, new energy, logistics, grain storage, photovoltaic and chemical sites.
• i2 Film: window and membrane films with up to 75% visible transmittance and up to 99.99% infrared rejection.
• CorroCool: a film variant combining cooling with corrosion protection.
• Materials range: cooling powder, Nylon-T masterbatch, ceramics and textiles for product makers.
• Project data: published case results such as a 1,200 m² rooftop at Citibank Tower in Hong Kong.

Industrial park owners in Vietnam can coat metal factory and warehouse roofs to lower indoor temperatures and cooling bills. Telecom operators and power utilities can apply the coating to outdoor cabinets and substations to reduce equipment overheating. Rooftop solar investors can test the coating on surrounding surfaces to improve panel efficiency.

The company reports solar reflectivity and mid-infrared emissivity of up to 95% for i2 Coating, with maximum surface temperature reductions of up to 42.9°C on buildings and up to 42% lower air-conditioning energy in architecture projects. On photovoltaic installations it reports up to 26°C cooler surfaces and 13.5% higher generation efficiency. As of October 2025 it cites 813,592 m² of applications and over 15 million kWh of electricity saved.

Rising temperatures and electricity prices are increasing interest in passive cooling that cuts air-conditioning demand without extra power. In Southeast Asia, factories, warehouses, telecom sites and rooftop solar plants operate under strong year-round sun, so reflective and radiative cooling surfaces are gaining attention as a low-cost energy efficiency and heat adaptation measure.

Founded by researchers from City University of Hong Kong; i2Cool (Hong Kong) established June 2021, with offices in Kowloon, Hong Kong and Nanshan, Shenzhen. Funding includes the HK Tech 300 Angel Fund, Pre-A rounds and a Series A led by investors including Trustar Capital, Peiport Holdings and Towngas. Awards include a TERA-Award gold prize and Forbes Asia 100 To Watch. Strategic partnership with Marubeni announced March 2025.