Expandable Energy

I would like to try the Do It Yourself techniques that I am reading about for a Renewable Energy Home but I am curious if the steps I use for a small home would work for a larger home? I would like to start out small and perhaps just power a small area of the house before I commit to a big project. If I know that it will work continually and effectively then I do not mind adding on. Are the smaller packages available so that I can add on to them at a later time with more of the material or do they work independently?