&gt; <i>While hot water may cause shrinkage in wool garments, for cotton and polyester t-shirts, the washer settings don&#x27;t make a big difference.</i><p>This is also more or less true of wool, in fact.  It&#x27;s not the hot water that shrinks a wool sweater, it&#x27;s getting it damp <i>and agitating it</i>.  The hotter it is while agitating, the faster it will shrink; being fully wet (as opposed to damp) mitigates the felting process somewhat.  It appears that cotton is the same way (although its shrinkage is less extreme and less permanent than shrinking a wool sweater!).  You can certainly get a wool sweater wet with hot water without shrinking it at all.  If you&#x27;re careful, you can wash it in hot water and agitate it to wash it properly, as long as you don&#x27;t overdo it, without shrinking it.  With some treated wools you can tumble dry on no heat, although I wouldn&#x27;t recommend it; but <i>under no circumstances</i> should you wash a wool garment (in whatever heat of water) and then put it in a dryer with any heat at all.  <i>That</i> will shrink it.<p>I knit, so I have extra awareness of how many people just don&#x27;t know what to do with wool these days, and I have to educate them if I want to give them something I made. :)