Whenever a person has asked me about working from home and what are the concerns, my response has always been the same --- the question will not be ~ how many hours are you working?~. The question should always be, ~ how do you intend to be a part of a team and commit to the appropriate level of communications to remain a part of that team?~.
Contrary to the opinion of most [clueless] managers, it is not about the slackers.
It is about communication among the team.
If you hire good employees, then you should not need to be concerned about the number of hours they are working, except to make sure they are not working too many hours.
.Lee Iacocca - "I hire people brighter than me and then I get out of their way."