ac can't cool house
So I live in austin tx and the nights are not getting above 80 degrees and the days are in the 90s outside, but at night the ac is not able to bring it down to 73 deg from about 78 deg. For exmple last night at 8:00 the thermostat said it was 80 deg(after showers and making dinner) when I got up the next moring the thermostat said 77 deg. A little info about the house the ac program is mon-sun 8am-8pm 78, and from 8pm to 8am 73. The house is a two story, three bedroom, 2.5 bath with a attic with blown insualtion. The windows are the engery efficient along with two glass doors. I have lived here for about 1.5 years and last summer it did not do this. So here is my question why is the ac taking 12 hours to cool the house three degrees?