Or the old fashioned way- bring spuds to the boil in an ordinary saucepan ( one you don't care too much about as it will blacken, remove excess water, turn down heat, put a bit of newspaper between saucepan and lid and it will steam and become nice and fluffy in about 30 to 40 mins, depending on size.
About 20 mins. Depends on the size, I suppose. Then toss them from steamer section into bottom part, having 1st thrown out the water, knob of butter, salt, even chopped onion, scallion, maybe a few herbs....and mash away.