Dryer vent flapper and ducting
 

I was walking around our house the other day and noticed that our dryer vent on the exterior of our house had no flappers on it. I will certainly be taking care of this in the next week or so, but it made me think of something else. We will be finishing the lower level (where the dryer is) over the winter, and I'm wondering if I should wrap the entire length of the dryer vent ducting in insulation before we drywall the ceiling. Anybody else done this or have any advice or ideas on the best way to do this?

Cory

I've got a vent with no flapper as well. The Big Box stores sell in-line plastic flappers ($5) that you can just add to the duct with gear clamps if you don't want to mess with the exterior part. I didn't see them 'till I'd already bought a new vent, but I'm adding it anyway (2 flaps better than 1?). I'm also re-doing my bathroom fan vent duct (which currently dumps straight into the attic!) & found pre-insulated flexible ducts which prevent condensation from dripping down into the bathroom. One length will do the bathroom vent & my dryer.

FYI - If you have an electric dryer, you can divert the dryer exhaust inside the house during the winter. Don't do this with a gas dryer due to the CO2, CO, and other exciting fumes generated by the burning natural gas.

I installed a dryer heat diverter last winter and it definitely helps warm and humidify the house - Winter Heat from a Clothes Dryer | EcoNewMexico.com. During the spring/summer/fall I flip the lever back to vent outside and I use our clothesline most of the time.

Tim

Why
 

Why are two flaps better that one? Less resistance, maybe. Less squirrel traffic?
Venting into the attic turns your insulation into a conductor. Mold too. I was up in my attic to change out my plastic corgatted chepo duct with an insulated type. Then I realized I may be able to crawl in but never crawl back out. Like a lobster. My son will be 12 soon, I'll just grab his feet when he's done.
Why is cooking inside with gas OK to do but dont vent your gas cloths dryer into the house? :eek:

My mom always has this box thing with a lever that flipped a valve on the dryer vent. When its closed it vents to the out side.
When you open it it vents inside the house...she woudl put a pair of stockings over the inner vent to catch any lint. This made a big differnce in how warm the basement was.

We do the same thing with our electric dryer. Used to have problems with dusty lint when we had just a screen on the output. Now I have a different design that uses a nylon sock-like filter. Seems to work better. I've seen types that have a water filled box at the output for lint catching but haven't tried one.