possible high electricity use tenant

[David Wolber]

We are currently leasing the office spaces in our building as gross leases.  Mostly are target tenants are therapists and wellness practitioners; single office type business that utilize shared waiting rooms.  The 2nd floor of our building isn't rent ready yet, but have had interest from a person who wishes to have a photography studio in there.  Our concern is that our rent numbers are based on a 5-day per week standard office use (lights, computer, etc) and this will be significantly more electricity use.  And of course, the building isn't wired for separate meters.

So in my head there are only two obvious conclusions: guess how much electricity they will use and set rent accordingly -or - meter or monitor their use somehow and charge them separately for the electricity.

There are a few circuit monitoring product's on the market for around $600 that seem feasible, has anyone used something like this?

http://www.brultech.com/greeneye/

Does anyone have any other suggestions that are not apparent to me?

Thanks in advanced!