Start with a home energy audit, it is the first step in making your home more efficient. An audit can help you assess how much energy your home uses and evaluate what measures you can take to improve efficiency. But remember, audits alone don't save energy. You need to implement the recommended improvements. Then find yourself someone to do a Load calculation Manual J and a Manual D on your home, you need both the home energy audit and the load calculations, one without the other is just throwing dollars out the window. Manual J and a Manual D do you no good if air is escaping, or being drawn into your home.