Vampires sleep in coffins and it is one of the most common images that vampires have in popular culture. This is partly due to the fact that vampires are often depicted as being a type of undead creature and that sleeping in a coffin would be a way for them to stay hidden from those around them. The coffin imagery also seems to serve as a metaphor for the vampire’s death and decay, and it is a part of their ominous presence.
During the day, vampires return to their coffins or cemeteries in order to avoid sunlight, which is deadly for them. While sleep is an important biological function for humans, vampires are soulless creatures that do not need to sleep.
The reason why vampires prefer coffins for sleeping is that they provide them with a concealable space that can be easily locked and sealed shut. Additionally, a coffin can block out noises and other distractions so that the vampire can get a good rest.
Many vampires believe that they must sleep in a coffin that contains soil from their homeland or from their graves in order to be able to recharge and heal properly. This is particularly true for those that reside in the demiplane of Ravenloft, where the earth from a vampire’s homeland can be used to create magical sanctuaries in which they can rest.
While the majority of vampires prefer to sleep in a coffin, some can also find sanctuaries elsewhere. However, it is a much more difficult proposition for those that must carry the dirt from their homeland or grave with them while traveling. For example, if Dracula needs Transylvanian soil to survive in London, he will need to transport several boxes of it with him to ensure that he can rest and recharge when necessary.