K.C.
Lisa,
When I had my first baby 8+ years ago, my pediatrician said that when it comes to temperatures (hot or cold), just go by how I am feeling. If I am comfortable, my baby will be comfortable. I now have three kids (the youngest being 8 months) and the simple, common sense advice I received from the doctor has worked just perfectly.
I live just outside of Austin and we have been having 100+ degree days. My hubby and I work out of our home so we keep the A/C temp at 74-75 degrees, with the ceiling fans going. This setting works well for us. We watch our usage as well since we are very conscious about not having high electric bills.
Hope this helps!
Smiles,
K.