To shave or not to shave

Question
I have a 13-yr.-old male Cocker Spaniel who is a house dog when I am home, but stays outside in a shaded patio area when I am at work.  The temperature here in Austin is constantly in the mid to upper 90's during the day.  I have him shaved twice a year but was wondering if I should keep him shaved for the summer.  Does long hair on a dog insulate him from the heat, or contribute to his discomfort?

Answer
I would shave him, but let about an inch of hair.  You can shave the underside shorter if you like.  Hair does act as some insulation and helps protect from sunburn.  To help cool him, you can also hose him off before going to work.  And make sure he has plenty of fresh water and shade.