Whenever people start remodeling, they want to replace their flooring. Today it is important to consider not only style and cost, but also whether or not what you are doing is safe for you in the home and also if it is poisoning ecologically.
The first thing you need to do is check out your existing flooring. It may not need to be replaced at all. Hard flooring can be finished, stained, pickled, antiqued, or painted for a new look without cutting down more trees.
However, if you do have to replace it, consider using cork flooring, since it is durable, uses no toxic adhesives, comes in many colors and designs, and is comfortable to walk on. And cork is easily renewable.
Carpeting collections dust mites, mildew, and pet dander, all of which are difficult to remove. It is bad for people with allergies, and is often made from synthetics which are not good for the environment. Carpet tiles are worth considering, since they can be easily replaced, one at a time, if damaged or stained. Another bonus is that they can be installed without using a professional installation service. Often these are made from recycled materials.
If you still insist on carpeting, please consider not using carpet padding. Not only are you paying more for the purchase and installation of this padding, but you are also shortening the life of the carpet. So there is more material being used, more chemicals, shorter carpet life, and it is harder to clean, since the padding is like a sponge, absorbing and collecting dirt and stains and odors that are almost impossible to reach without using even harsher chemicals.