Washing dirty linen yourself rather than relying on a machine could help cut down greenhouse gas emission levels, according to a Queensland University of Technology researcher.
For example, washing and tumble drying a dirty T-shirt consumes three-quarters of the energy used in manufacturing and using it, said Francisco Javier Navarro of the QUT Institute of Sustainable Resources.
He has been commissioned by the Cotton Research and Development Corporation to undertake a "life cycle assessment" that compares the environmental impact of cotton and polyester T-shirts on their production, use and disposal stages, the "cradle to grave" approach.
His investigation takes into account the entire life cycle of a T-shirt, and measures the environmental impact of growth and production of the materials, construction of the garments, transportation, retail, wear and disposal.
Navarro said that throughout a T-shirt's life, made and sold in Australia, almost 75 percent of its carbon footprint would be caused by machine washing and drying at home.
"Research shows that household washing cycles consume about 19 per cent of the total lifecycle energy consumption, whereas tumble drying consumes about 53 per cent," Navarro said.
"As a way to compare, the production of raw cotton fibre uses 10 per cent of the energy and the different stages of cotton T-shirt manufacturing use up 12 per cent of the total energy. The manufacturing of polyester T-shirts consumes slightly higher amounts of energy.
"This means our decisions on washing our clothes have a big impact on the carbon footprint of our clothing. It makes a huge difference in energy consumption to hang clothes out on a washing line to dry instead of using a tumble dryer."
One of the objectives of Navarro's research is to analyse the effect of increasing the number of times T-shirts are worn before washing.
Navarro said the use of "smell-friendly" fibres would also assist in increasing the number of times a shirt is worn between washes. "Research shows that polyester is related to more intense sweat odour than cotton," he said.