Where do we start to turn Green?

I have been thinking about the things that I can do personally to help the environment.  I realize new home builders are using all kind of environmentally friendly products but what about the older homes?  What can we do?  I realize that newer furnaces and air conditioners are more efficient but what if the older ones are still working?  I can't justify replacing them now.  I replace the filters and have them checked periodically to make sure that they are running as efficiently as possible.  I know that the front load washers use less water - another great idea when replacement is necessary. 

I purchased the new LED Christmas lights and I recycle.  I purchased a live wreath so it can go to the compost.

Please give some thought to what you're doing and share those ideas with me.  Our world thanks you and so do I!