very high electric bills

[Mike Landry]

my tenant had a $350 electric bill last month, almost 3000 kwh. 1600 sqft brick house built in 2005.  What is the most likely culprit for this? I have someone coming to check out the ac this week anyways. Any other possibilities or things I should check? He said he's had a bill like this before.  He also has in the office 4 computer screens and multiple computers running 24\7 for his business.  I didn't believe him at first but he showed me the bill. It wasn't even that hot in Houston last month. 

All ideas are appreciate. Any electricians opinions here?