It is interesting that they suggest that a room that progressively gets colder through the night might help you sleep better.  I&#x27;m currently living in a fairly warm part of Japan and we have no heat in the house (or air conditioning).  I definitely sleep better here than I do when I&#x27;m in Canada or the UK.<p>There are probably many other factors (for example, I sleep on the floor in Japan and use a &quot;pillow&quot; that is really just a sack of grain -- it might sound strange, but it is <i>so</i> much nicer than the overly soft trappings of western bedrooms IMHO).  I had never really considered temperature as being a factor, though.