Just had central a/c installed. Never lived in a house with it before so I am not familiar with its operation. House is 1000 square feet on unshaded property in Maryland. Unit is 13 seer 1.5 ton. Attic is well insulated with attic fan. On 100 degree day the unit will run nonstop and maintain 71 degrees indoor temp. Outlet temp at register is 54 degrees. Is the unit supposed to run 100% of the time on a day like that or is it supposed to shut off once in a while? I'm just wondering if the unit is undersized or working properly. Thanks