The National Sleep Foundation has summarized three important parts of a "sleep friendly" environment for children. They are noise, light, and temperature. The noise generated from the household and neighborhood can disturb sleep patterns. Unwanted light levels can disrupt sleep, although complete darkness isn't necessary. A room temperature that is not too cold, but is cool, makes sleeping easier. Economic and security concerns may influence each of these factors.
PositiveTip: Seek to provide a "sleep friendly" environment for your children and yourself.