I’ve vented my electric dryer into my basement for the last 13 years now and I'd never switch to venting it to outside.
It most definitely adds moisture to the air, but in the winter, it’s actually an excellent method for reducing static electrical shocks, prevalent in dry winter air. The little bit of moisture that it puts in the air won’t keep your basement damp for very long after the dryer shuts off (my dryer typically only runs for 40 to 50 minutes). My basement temperature typically increases 6 to 8 degrees Fahrenheit however, it only increases my living room/dining room temperature by 1 to 2 degrees Fahrenheit, but anything is a help (in the winter).
Another plus is the way it makes my house smell so good, as I use Downy fabric softener sheets in my dryer. I don’t even want to leave the house after that because it smells so good throughout my house!
In the summertime, I leave my basement door open with my upstairs air conditioner running (a 240 Volt window AC unit rated @23,700 BTU’s), which quickly removes the moisture from the air.
However, I don’t vent my dryer unscreened. A girlfriend was ditching a pair of panty hose, so I cut one of its legs off and placed it on my 4” dryer vent hose per use of a single thick rubber band to keep it secured. I empty the stocking every other dryer load for max air flow, but I could actually skip emptying the stocking for several dryer loads if I got lazy. I’m into efficiency, so I empty it every time I use my dryer.
Incidentally, that same rubber band has lasted for the last 13 years, which is somewhat surprising, as one would tend to think the heat, if not age, would have made the rubber band succumb by now.
