Closed in patio used as a second living area

[Gabriel Graham]

I have a contract on a house in Oklahoma.  The square footage advertises was around 1900.  The appraisal says 1700.  The difference being a patio that was enclosed and is now used as a second living area.  The slab is not as think as the house of course and it appears the HVAC is not connected to the patio room (basically just gets heated and cooled by the room joining the area).

What kind of difference does this make on purchasing a house - do you value it on the 1900 or the 1700?  

[Kerry Baird]

That area does not appear to be permitted.  I'd value on the lower square footage.