instead of using your heater or cooled air you've paid $$ for ,why not use outside air for combustion of your Gas dryer? Install the dryer in an airtight closet install a vent for fresh air that the dryer would pull in and of course the normal exhaust gas dryer venting. I'll bet you'd save enough in lower heating and cooling costs to make it worth the one time trouble. Any ideas??
In the winter, up north where I live, that would not be a good idea since the air I would need for combustion and to dry the clothes would be extremely cold and would slow up the drying process and require the dryer to run longer. Dryers use a lot of air for both drying the clothes and for the combustion of the nat gas. Also I like the fact that running the dryer will exchange some of the homes air helping to keep the home's atmosphere fresh. Some seemingly good ideas are probably just too good for me. There would probably be no cost savings after this investment.