L.B.
Hi M.!
I just went thru the same thing with my daughter, she turned 3 in Oct. she would go to the 'potty' at school, but wanted nothing to do with it at home. we had several people suggest to us that "usually" it's the other way around (potty training usually happens at home and they don't want to go anywhere else)but since he's learning at school he's not wanting to go anywhere else. only thing you really can do is just keep asking him at home say every 30 mins or so if he needs to go, and try sitting him on the potty. you will have to be patient though cause it may take awhile (took my daughter about 6 1/2 months before she took to going anywhere, lol!) but once he goes at home for the first time and you make a good "praise" over it :D you shouldn't have any more trouble with him not going....
good luck!
L.