Living in a house deemed to be haunted would most likely not be found on the top of many bucket lists. Although for some, this statement may not be true. The truth of the matter is that many would actually relish the opportunity to be a part of a story or history as profound as those of most haunted houses. To own, not only a house, but a piece of history.
What would it do to a homes value?
Obviously value is determined through the theory of supply and demand. While the number of people wanting a haunted house is limited, so are the number of houses suspected to be haunted.
One could approach the situation and say that if the property is priced low enough, those that either don't believe in ghosts and haunted houses or those that do but dislike the idea of living in the situation would buy the property anyways. In this case the stigma would obviously decrease the houses value.
Another approach would be to have your agent capitalize on the short supply of supposidly haunted houses. So long as the agent could find buyers wishing to own a haunted house, it could elevate the properties value.
Ok, now prove it!
In order to market a property in the manner described above without opening yourself up to litigation you would have to prove that the house is in fact haunted. I suppose the option is there to call one of the many ghost hunting type shows but I'm fairly confident that most of what they do is clever effects and editing.
So, in reality there is no definitive way to prove that the house is haunted from both the sellers and buyers point of view. This doesn't mean that someone won't buy the house because of it's believed hauntedness but, for the most part I believe the stigma will decrease the homes value.
The question still remains.....
Would you want to live in a haunted house?