My first suggestion will not only help you inside your home but outside as well.
PLANT A TREE
That's right plant a tree... hang on wait not just any tree and not just anywhere. You want to plant a Deciduous tree. This is the type of tree that loses its leaves in the winter. You want to plant it on the southern side of your home. Heck plant two or three if you have the room. By planting a Deciduous tree on the southern side of your home you get year round benefits. In the summer your home gets some protection from the hot sun which means you don't have to run your Air Conditioner as much. In the winter the leaves fall off the tree and allow the winter sun to shine on your home helping to warm it up which means less heating. This means less electricity used which of course means less fuel burns. It also means your are creating new habitats for birds and other animals.
Now this is something that is simple and easy to do and can be very inexpensive. The best site to use to get started is Arborday's site just click here or type in arborday.org. They have all kinds of information about trees, including which ones grow best in your area (I suggest the fast growing variety for shade sooner) the size and shape they will be, how to care for them... . Not only that but for the cheapskate in all of us if you join the Arborday Foundation for $10 they will send you 10 trees. You can mix and match get some shade trees for the south side of your house and get some fruit trees for anywhere else and lower your food bill. Or get all shade trees and share them with your neighbors and have a lovely cool tree lined street for taking walks on. Even if you don't join the site has tons of great information. So get started go check out a tree.