Actually, if the inside of your house is hotter than the air outside this is a sign that you are getting to much sun inside your house. Try adding some retractable sun shades or curtains over any east or west facing windows.
To see if this will make a difference hang a large sheet over any window where you can feel heat from the light coming in. It may look unattractive but it can help you guage whether adding shades is worth the $$$ and effort.
Below is an example of the shades I put in my house. I have reduced my home utility bill by about 10% in the last two months with $500 worth of wooden/bambo shades. The shades also gave my house an updated look which several guests have commented on!
