To meet the new energy standards. Hot and warm water uses electricity (or gas) and costs money.

I presume solely for energy savings as my Fisher Paykel GWL11 washable woolens cycle uses a so-called warm cold temp. for better rinsing as per the owners manual. It is warm to the touch as these are not dumbed down water temps.

Warm/Cold rinse on the F&P Woolens cycle is not so much for more effective rinsing as it is for avoiding thermal shock to woolens being washed in warm and rinsed in cold.ÃÂ It's not heat per se that shrinks woolens as much as a large, sudden change in temperature while wet.

lucky_12, unlike the wash cycle, the purpose of rinsing is simply to dilute and suspend the remaining detergents and soils. The temperature of the water has little to no impact on this.

Warm rinses do help to relax the fabric a bit, and thus would probably be of some benefit if you line/air dry frequently. If you use a tumble dryer though I can think of no gain in using a warm rinse (other than thermal shock effect in the case of some particular delicate fabrics).

Warm rinses were needed in the days of washing with soap (I've heard mention of a couple machines years ago that had either agitated or spray rinses with hot water). Synthetic detergents largely eliminated the need for heated rinses.