> Other than that, in terms of energy usage, heating/cooling, etc., I would imagine the cost savings of having people work remotely are considerable.

You'd have much higher costs around compliance and taxation, which represent an ongoing expense since laws are always changing and people moving. That probably works out after a few employees in any given state. Companies also lose money by flying everyone in once or twice a year. Now that I think about it, I wouldn't mind seeing some math on the subject.