How to decrease your warming costs?

If you are staying in a huge, own house, you probably are glad because of that, mostly in the time of summer time. But what about winter? How much cash you are wasting every year for heating? If your mansion is older then ten years, it perhaps does not have a proper wall insulation. Or probably even you do not have a hi-tech windows which could protect your home from wasting the hot air. When you like to reduce your costs, you have to spend some money at the beginning.