Green Garage Doors--they really do exist!
With all this talk about greening the home, there are a few things that can fall through the cracks. Garage doors have not frequently been thought of as efficient or energy saving or much more than just decoration--until now, that is.
Insulation
First off, garage doors can, and often should, be insulated. These better barriers can really save the house a great deal of heat loss and air leaking. As an example of the other extreme, the garage door in my last home was barely more than a piece of plywood, and it made the whole three-car-garage into an oven in the summertime. All that collected heat spelled trouble for the rest of the house, as it meant that we had to keep the air-conditioning on for more hours, just to counteract the effects of the over-heated adjacent garage. This was enough to convince me to be sure that we had an insulated garage and garage door in our current home. I've learned that you can even add insulation to some existing garage doors--check with your local garage door vendor for details.
Tax Credits
Perhaps even better news is that with qualifying garage doors, in the States, we can now get tax credits. The credit amounts to 30% of the cost of the door or up to $1500! The first of the qualifiers is that the garage door must be insulated, and expected to last at least 5 years. As you might imagine, the garage itself must be insulated as well. Technical factors of the door include a U-factor minimum, a Solar Heat Gain Coefficient Limit (for doors with windows in them), and air filtration control. Ask the door vendor/installer about these factors, as well as for a breakdown of pricing showing material and labor.
So if you are in the market for a new garage door, you have a good opportunity to be good to the earth, and save money in the process. Certainly, the savings come both from the tax credit and from the long-term savings you will have by saving energy through better insulation.
(Also see http://www.dasma.com/ for more information.)