If you are considering a energy saving project without going through the blower door test you can perform a free DIY air leak test to help you determine where the biggest leaks in your home are coming from.
Close all your doors and windows, the turn on all the exhaust fans (furnace, bathroom, kitchen, etc.). Hold a candle or incense stick near different areas in your home where hidden drafts may occur. Before you start make sure that the flame or the tip of the incense does not get near curtains or furnishings.
You’ll want to check around doors, window frames and near electrical outlets. By using this inexpensive method of testing for air infiltration you can start with the project that will have the most impact.