Canadian startup Element Four has revealed plans to ship a residential device to create drinking water from air next spring.

The WaterMill device works by drawing air across coils that cool it to the " dew point", so that it condenses. UV light then purifies the liquid. The intention is for the device to be fitted to the outside of a house, and then channel water to sinks, fridges and other water using appliances.

Atmospheric water generators are not new, but chief operating officer Rick Howard said that the WaterMill will be more efficient than previous attempts, because it constantly optimises itself to suit environmental conditions such as air temperature and humidity.

"Here in British Columbia, electricity costs six cents per kilowatt-hour, and we're making water at the cost of two to four cents per litre," said Howard, adding that the company is hoping to sell the unit in markets where water shortages are commonplace, including the US, Saudi Arabia and Australia.

The device, which costs $1,700 (£1,125) installed, will create roughly 12 litres of pure drinking water a day with a relative humidity of 65 degrees and 70 degree temperatures. It requires a minimum of 35 per cent relative humidity and 60 degrees to operate.

The development of the WaterMill was almost an accident, explained Howard, who said that the company originally focused on developing the core atmospheric water technology behind the unit.

The technology can scale to larger applications, and could be used to create large "water walls", in which a number of bigger units are strung together to provide water in emergency situations, for example. Howard also sees applications in developing countries currently battling water supply and quality issues.

"As far as I know, the technologies proposed for this don't tend to be as high power, for example, as desalination," said Duncan Stewart, director of research at Deloitte Canada, which has highlighted water as a key, but often ignored, component of the clean tech market.

Element Four is funded by friends and family, and is not seeking venture capital input.