I can certainly collect some pictures for this but I'm hoping on sound engineering & design principles I'll get a recommendation worthy of executing to that meets code.
I have a vented clothes dryer. I do not have a ventless dryer and I am considering buying one. My main reluctance to buy one is that while they are costly and mechanically more complicated (therefore I expect higher repair costs), they are still going to cost significantly more to run (operationally) than a gas dryer. Sure, I'll buy new clothes more often in the long run, but I like and prefer to own a gas dryer.
I live in BUFFALO NY (the Southtowns). We're famous for getting 4' - 8' overnight. More commonly we will see 12" on any given day. It melts quickly too, then we get more. Its mostly lake effect snow.
The home we bought is a gable style, built 1986, eaves are closed with soffits, vented every few feet. Full Ridge vent. One gabled end is near bedrooms and bathrooms. The bathrooms are not vented correctly. I'm planning to do two separate and direct roof vents for those. For the other end of the home, is the kitchen (nothing externally vented), and a glass sun room off the kitchen which sits right behind a mud room as well as the entrance to the kitchen and then the garage. The mud room and the entrance are essentially "inside the garage" if you were to draw a box.
So, The dryer: Currently goes through the back wall of the mud room with flexible foil vent & two 90's, straight up 8' into the attic, sloppily laying across the attic an additional 7' or so (towards the 2.5 garage gable), and then up 4' to a flanged dryer vent on the roof which is up from the edge probably 8'.
Needless to say, this is not to code on many levels. Exceeds 25' calculations with bends, uses far more than 8' of flexible tubing, and sadly is not even inline with the spot I would drill a hole in the roof if I wanted a roof vent (I would position it inline with the dryer shortening the length of the run and also get it in the weather barrier region closer to the edge.
Discussion #1: [Decided against: Least attractive least functional use of space, long run]
Now with all of this said, I'd totally go out the back wall directly behind the mud room, but that would put it inside of the sunroom/glass room. So Off to the side of that is a rear 32" garage door, and a window... so 3' off that puts me near the other side of the garage. If I split hairs, I can say 30" and go between the window and door, but that still violates 3' (however, no one lives in the garage) nor will the window ever really be open. this run with rigid ductwork would be approximately 22' and would require at a minimum (2) 90's and (1) 45. I could use This and meet most of the code.
- Since posted, I've come to realize that to have it be the least bit appealing, it will require (4) 90's. Still possible to get the "free" Dryer-ell product, but at 1.5'*4 = 6' + 22' = 28' but violate code still (technically) by placing near a door/window opening
- I can go an extra ~8' and be at 36' and code legal - this is equal (likely worse)than #3
Discussion #2: [Decided against - just pure stupid for Buffalo]
Next, I'd do the roof venting still, but ideally I'd shorten the run and move the vent towards the edge and into the ice barrier and use this Roof Vent to have optimal venting. It would be near 20' and would require (1) 90, and approximately (2) 45's. Also, if I did this, I'm pretty confident I would have to be shoveling snow off the roof - OFTEN. Also, since we are a family of 3, we wash a load at least every other day. I expect I'd quickly have ice issues, and would need a melter. (there's one up there already over a cathedral ceiling).
Discussion #3:[Most likely approach] Gable vent out the side of the garage. Main reason against this is the length (about 33') and likely efficiency loss. The current Dryer is a LGQ8611PW0 and will accept up to 44' with (2) 90's. If I use the ones linked above, I should be in good shape (64' max).
- Still (2) 90's 1.5*2 = 3' + 33' = 36': only 2 90's and overall a straighter run than #1, weighs better than #1 due to turns (in my opinion)
- Legal, good use of space, and not functionally ugly
- Run would have to cross over the attic space access door, but not a big deal. I could probably add a quick access door/disconnect for cleaning
- Don't believe this would be a code issue, and even with a "V" shape run using two 45's it would be one less bend than #1
- I probably wont use a "Dryer Ell" and take a 12' hit (48' total), so LAST question needing an answer: What effect will an extra 10-15' have on drying performance, effectively?
Discussion #4:[Attractive for length of run] Soffit vent. Use something like This And then keep it very near to the sun room, and garage door, but it will give me the 3' needed in all directions. The run length would be about 25' and using two of the wide 90's It'd be much shorter of a run than #3, and snow would not be an issue.
- Actually needs an additional 90, total of 3
- Basically 3*1.5' = 4.5' + 22' = ~27', If I go to regular 90's, 37'
- This would give me 11' less than #3
- Clean out could be trickier with a soffit vent area harder to work in if I need to get in there.
- Lint would be dumped in a "main" area frequented by feet
- Hot wet air rises, so it is POSSIBLE even with good design it may find its way back into the attic area
in all cases, I have to clean the assemblies, and the longer the run, the less efficient it will be. If someone can't make the argument that electric ventless is more efficient, then I am going to do one of these options... But which is the best? Have I missed an option? (and please don't tell me to hang the clothes up. Of course we can, but that's not a full solution).
PS: I didn't mention venting via the subfloor area since this IS over the garage slab, not conducive to bringing it into the basement and out the sill, but it is possible.