Using harvested rainwater can make a major dent in the water bill.  And when using insulation features, electricity usage is reduced to a large extent.

Hot water insulation reduces geyser/heat-pump costs.  And room insulation maintains the room temperature.  A radiant heating and cooling system throughout the floor of the home makes temperature control cheap.

All these savings result in a reduction in living costs and eventually, a great return on investment.  Within about ten years or less, the extra amount that we paid for the green home is retrieved with these savings.  We also gain a profit when we sell such a home.

To add to this, green homes have a low impact on the environment, making them even more valuable.