SHANGHAI, Sept. 5 (SMM) -- Air conditioner manufacturers saw profits fall by nearly 50% in the year since copper prices surged by 40%. In some cases, manufacturers replaced copper connecting tubes with cheaper aluminum material in order to cut costs. In addition, since copper is a scarce resource, it would seem natural to use more aluminum, but this substitution is still controversial. In addition, low-end models of air-conditioners are unprofitable due to high costs, leaving medium and high-end models to generate profits. Industry experts believe aluminum tubes are weaker than copper, while corrosion resistance and thermal conductivity remain untested, which increases the urgent need for relevant industry standards for materials used in air-conditioning tubes.