Dryer Vent Insulation

[ewang]

I noticed the uninsulated metal dryer vent I have is sweating like crazy with the cold air cooling the metal, and it condensing inside the heated space.

Aside from a taped hack job of insulation around it, what off the shelf solutions can I use for my electric dryer?

I don't think it would be wise to use insulated flex duct, just in case the high temps could melt the plastic. Why can't I seem to find anything for this?

 

[shooon]

Is there a flapper cover outside where the drier vent exits the wall?
There should be some form of check to stop most of the cold air from backfeeding into your drier.

There is insulated ducting you can buy, or you can also buy sleeving and insulate the existing duct yourself.

 

[Highbeam]

When the dryer is running the duct should be hot and dry. With it not running there should be no air flow in the duct. Especially none bringing cold air into the home.

 

[ewang]

I've got a plastic backdraft damper, but with -30degree nights and wind, you can feel the pipe get cold.

 

[R.Anderson]

I've got a plastic backdraft damper, but with -30degree nights and wind, you can feel the pipe get cold.

-30 nights when has it got that cold this year here? Just curious because you said you just noticed this problem.

 

[Junkman]

I would purchase 4" round metal duct, and only use a short piece of flexable aluminum ductwork between the round metal and the dryer itself. You can then wrap the metal duct with duct insulation, and not ever have to worry about a fire in the duct because of lint getting trapped. The metal duct is smooth enough that the lint will move to the exit point. You can also take it down every couple of years and check its condition.

 

[larry4406]

I would purchase 4" round metal duct, and only use a short piece of flexable aluminum ductwork between the round metal and the dryer itself. You can then wrap the metal duct with duct insulation, and not ever have to worry about a fire in the duct because of lint getting trapped. The metal duct is smooth enough that the lint will move to the exit point. You can also take it down every couple of years and check its condition.

This

 

[ewang]

-30 nights when has it got that cold this year here? Just curious because you said you just noticed this problem.

Not this year, but last year I noticed it. I didn't want to get into insulating it last year, but became interested this year once we had a cold spell.

 

[matt_i]

If you use Roxul insulation it will withstand something ridiculous like 2000F. In my opinion perfect for direct contact with non-chimney heated ductwork.

My dryer vent has a penetration with 4 plastic flaps that hang vertical in normal operation and then straight out horizontally when drying. It seems more reliable than the single-metal-damper versions. Also it outputs under the deck, thereby shielding it from direct wind penetration.

 

[James-W]

I have never seen, or even heard of, a dryer vent being insulated. I am sure you can do it but with a proper installation I am not sure exactly why it would be necessary.

 

[Highbeam]

You're flapper on the vent cap is not functioning properly then. They do require maintenance. Specifically, cleaning the seal area. If that flapper is missing or stuck open on a lint pile then outside air can easily be pulled through your dryer for several reasons.

Your problem isn't lack of insulation on the duct, your problem is a faulty check valve.

 

[Jackfre]

I'd agree that the flapper is not functioning correctly. Not sure if this will be of any help, but I like the looks of this magnetic adapter from Lee Valley.

http://www.leevalley.com/US/garden/page.aspx?p=74597&cat=2,42194,67373

I have all metal ducting on my dryer, but I think this will make a nice secure transition and will likely install it on mine. I was not happy with trying to "thread the needle" to the vent connection.

 

[James-W]

Lint sticks less to a rigid straight pipe than it does to a flexible "ribbed" type pipe and you have better air flow. I would recommend staying away from a flexible "ribbed" pipe if at all possible. It may be a big pain in the neck to use a rigid dryer vent, but you will have fewer problems if you do.

 

[bbrz]

Get a box of 4" flex duct, pull out the interior flex, disconnect one end of the rigid metal pipe, and pull the insulation over it. Safe, insulated, and done.

 

[Firebird 1]

Never heard of an insulated dryer vent, but if you want one I would agree with Junkman. In my county it is code to use hard/smooth pipe for DV. The flimsy aluminum flex stuff and the plastic type is Forbidden.

 

[larry4406]

Never heard of an insulated dryer vent, but if you want one I would agree with Junkman. In my county it is code to use hard/smooth pipe for DV. The flimsy aluminum flex stuff and the plastic type is Forbidden.

I build new houses in Montgomery County MD and all of our dryer vents are smooth metal duct (not flex) and where they pass thru unconditioned space (ie attic) they are fully insulated.