If you are experiencing excessive heat and moisture, the very first thing I would check is your dryer vent. Make sure it is not clogged and that it still vents to the outside without dumping any lint into your crawlspace.
Dryer lint in a dryer vent causes a very high percentage of housefires every year. Take your shop vac into the laundry room, remove the front panel to your dryer if you can, and vacuum all of the lint you can reach out of the thing. This chore should be worth a few bucks in loose change as well! After that, pull the dryer out, disconnect the dryer vent, and vacuum as much of that out as you can as well. If the dryer vent has ANY plastic or vinyl flexible vent hose, discard it immediately and replace it with a flexible METAL hose. Then check the crawler and make sure all the fittings are sound and that the vent is clear outside. Make sure there aren't any sheetmetal screws driven into the vent, this is a code violation because the screw tip presents a place for lint to catch and collect.
Beyond that, if your dryer hasn't been serviced in more than 5 years, you are probably due. The service guy will do all of these things for you too, but you will have to pay him to do it.
By the way, if your dryer is a sears, hotpoint or GE, you can call GE's customer service line at 1 800 626-2000, 24-7, 365 days a year, even in the afternoon on thanksgiving!