The house paints that promise much more than colour

Martin Zhu, chief executive and co-founder, says the paint made by i2Cool was tested on the roof of a shopping mall in Hong Kong – but only on one of its two buildings, in order to find out whether there was a noticeable effect in terms of reducing the costs of running that building’s air conditioning (AC).

“We used a power meter to measure the energy consumption of the AC system,” says Dr Zhu. The cost of running the AC duly fell in the painted building, by 40%, he adds.

Dr Zhu first began working on the paint while a doctoral student, and he mentions that early versions made around 2017 contained silver, which made it very expensive – more than $100,000 just to cover a small area. Years of development later, it now costs around $10 per square metre of coverage. It also now comes in a variety of light colours, including grey, yellow and green.

Researchers have noted that highly reflective coatings for passive cooling applications need to be resistant to dirt and soiling, for example, to avoid their efficacy dropping overt time. And glare from ultra-reflective roofs risks heating up nearby darker structures, a 2020 paper suggested, external.

The paint from i2Cool does not contain heavy metals and uses a water-based emulsion, and while it is not biodegradable, it can be recycled, says Dr Zhu.

The company’s latest major project is the Dubai Mall. The roof of this sprawling complex – the largest mall in the world by total area, external – will eventually be fully coated with the paint. A 1,000 sq m section has been completed to date.

While not yet available in Europe, that could change, says Dr Zhu. “We are discussing with some distributors in the UK,” he says.