Venting anywhere "inside" is a bad idea. Keep in mind that a lot of lint gets through your screens, and venting into a crawlspace will cause a huge lint buildup over the years, and that equals a major fire hazard.

I believe venting indoors is illegal in many states (if not all). I know it's illegal in mine (Ohio).

As part of your decision process you should consult your dryer installation manual. Many have their own specific requirements.

The more turns and elbows you have the less air flow will be available creating a lint trap and potential fire hazard. Also you must consider how you will clean your duct which is required periodically.

Guess I'm not expressing myself well: it wouldn't be indoors either way. The pipe will terminate outdoors, either 'out doors outdoors' routed through the crawlspace, or onto a covered deck with no elbows, but [seems to me] heat and steam issues.

Cleaning would be the main issue for me. You should do it at least twice a year and by the sounds of your elbow-ed pathway, that would be a big hassle. Eventually, you'll also have to replace the vent pipe - would that even be possible?

Your manual will tell you whether you can make that many elbows. Generally there is a maximum run allowable, and each elbow counts as a certain number of feet of the run.

As long as your covered porch is not an enclosed covered porch, then I don't see a problem with venting straight out as your builder suggests. It seems the best, and easiest, way to do it.

Sorry!

Could you go up along the wall then out through the "attic" space" in the roof of the covered porch, discharging at the edge of it?

Molly~

How much laundry do you do? That would make a difference on either consideration. Sounds like you have a layout problem. Any way to move the dryer a few feet and avoid both problems? Or redesign the deck a bit?

Will you be using the deck at the same time you're doing laundry? If it's just a covered deck it doesn't sound like it's going to trap any steam or heat. However I sure wouldn't want a dryer vent blowing onto a deck either since decks rot out fast enough without pouring steam onto them.

As said, elbows are traps and trouble. No, not huge but again it depends on how much laundry you do.

Or you could get a condenser dryer and avoid both issues! But no, I wouldn't recommend that.

OK, it's a little clearer now.

Given that both are outside, it just comes down to the basics of the longer the length and the more elbows, the more resistance for your dryer to airflow. Granted, the distance you are talking is not at all bad, but less is always better.

FWIW, my laundry room is also on the second (ground level) floor and vents right to my covered porch. The only downside is a buildup of lint on the one area of the porch I have to hose off 2 or 3 times a year. On the plus side the total lenth of my vent run is about 18" and the dryer rocks (very fast) with that.

The "laundry smell" is the only downside I see of venting out to the deck. Anyone sitting out there will always know when you're doing laundry. If that wouldn't bother you, then a direct path out through the wall would be great. I wish I had that. Dryer performance will slowly deteriorate if you use the path with many elbows, unless you're vigilant about cleaning.

Hard to know without seeing the proposed installation directly...

As mentioned, a fair amount of lint makes it past the screen inside your dryer. I wouldn't want that coming out on my deck. A straight shot is always best, but doesn't always work for everyone. 3 x 90's with six feet shouldn't be a problem, but as others have mentioned, check the manual. If you have room, check out the dryer ell (http://www.dryer-ell.com) as your not derating your setup as much using this large radius piece. The same company make something called the dryer box to tidy up installs that go up and down. If the crawl space has good access, consider putting the *hard* duct together with clamps so you can disassemble and clean the setup more easily.

Check with your local building code official if there is one...as this sort of thing is usually regulated in terms of how many elbows per feet as too many is indeed a fire hazard.

I explained this in another posting, but it seems more applicable here. Most states' building codes limit dryer vent lengths to 25 feet. You must add 2.5 feet for each 45 degree bend and 5 feet for each 90 degree bend. You have 6 feet of hose with 3 90 degree bends. Therefore, 6 feet + (3 x 5 feet for 3 90 degree bends) = 21 feet of effective length. I would check with your local building codes, but you're probably ok!

Thank you, rdowia: excellent advice.

Also check your building code for an exception allowing a longer vent, if the dryer manufacturer allows it.

Don't vent it to your deck, you will always regret it. I have a 90 bend then 20 feet to a wall. It is fine. Most dryers can handle up to 60 feet of vent. Bends count for extra "feet" and there is no way your set up will surpass what the dryer can handle. However, do think about clean outs and easy access. That is important.

link: Whirlpool: Exhausting Dryers.pdf