This covers the whole project from initial planning to the paint on the walls to the landscaping. This is more than just adding a nicer window or refrigerator, although they are a part, many of the most effective strategies start at the top.
Consider this analogy. If I choose to sit in the sun, there are many strategies to stay cool and keep from getting a sunburn - hats, fans, sunscreen, light colored garments, umbrellas, etc. Or I can choose to sit in the shade...This is why planning from step one is important, and will net the greatest gains typically with the least cost.