A woman dresses in casual summer clothing during a "dress-down week" launched by 32 office buildings in Shanghai to save energy, on July 22, 2008. [Photo: cnsphoto]

A mere casual Friday is not enough in the scorching summer heat. Shanghai's office workers are dressing casually every day this week to save energy.

Tens of thousands of white-collar workers in Shanghai's busy Lujiazui area have joined a campaign to dress down for a week and lessen their use of air-conditioning in the office, China News Service reports.

In the 32 participating office buildings, light-colored shorts have replaced business suits and ties, and the women are pleased to be wearing playful clothes during the week.

Every office has raised its room temperature by two degrees, to 26 degrees Celsius, the report says. In one business week, that will save enough power to supply 30,000 local families for an entire month.

Besides easing dress codes, many buildings have also launched side projects. The landmark Jinmao Tower, for example, is encouraging its workers to come up with energy-saving tips, and is offering rewards for good ideas.

The dress-down campaign is an extension of last year's event, in which workers shed their suits for one day only.

The organizer expects support from even more office workers next year in turning it into a month-long event, China News Service reports.