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Valuable Heat going out the Clothes Dryer Vent

Post in 'The Green Room' started by HumaneSocietySteve, Nov 16, 2008.

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  1. HumaneSocietySteve

    HumaneSocietySteve New Member

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    Hello All,

    I am hoping some of you "Heat Grinches" out there have had the same thoughts I have about keeping all that heat going out the clothes dryer vent in the house where it belongs during winter months. I have had this thought every winter for several years but have never came up with a good system to re direct the heat into the house when needed. I have looked for a simple diverter switch/box that would allow the home owner to divert the heat into the house during winter months and then in the spring back outside but have never found one.

    Has anyone solved this problem? Please let me know if you have any ideas on where to find this type of diverter or how to make one. Any and all input welcome.

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  2. EatenByLimestone

    EatenByLimestone Minister of Fire

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    How about homemade aluminum heat sinks on the exhaust pipe. A small roll of Al flashing would go a long way.

    Matt
  3. fossil

    fossil Accidental Moderator Staff Member

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    If you can devise a way to extract heat through the use of a heat exchanger, it might be worth a try. If you simply divert the dryer exhaust itself into the house, or anywhere except the outside atmosphere, you're gonna be in violation of NFPA 211 standard, and likely local code. Rick
  4. crazy_dan

    crazy_dan New Member

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    I guess it might go with out saying but, I would only even consider venting an electric dryer this way.

    But I was at the Hardware store the other day and they had a lint trap for venting an electric clothes dryer inside.
    I am thinking about giving this a try, my wifes parents dryer has vented inside into one of those lint traps that you add water to as long as I have known them.
  5. LLigetfa

    LLigetfa Minister of Fire

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    Venting a clothes dryer inside can result in too much humidity resulting in mold and rot. Heat exchangers can build up lint and become a fire hazard. Extracting too much of the heat would result in condensation in the exchanger.

    Why not hang the clothes out on a line?
  6. Corey

    Corey Minister of Fire

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    The first stipulation is NEVER to do this with a gas dryer as they vent the fumes as well as heat through the exhaust.

    On the electric side - at the risk of being in code violation - I've decided the heat is too valuable also. Not only are you loosing the dryer heat and humidity, but you're pulling a couple hundred CFM of air out of the house and replacing that with cold dry air from outside as well. My quick solution was to build a 16" x 20" box out of 1x4's, glue on a piece of 1/4" paneling for the back and duct tape a 16x20 HEPA filter to the front. Bolt on a little flange for the dryer hose and good to go.

    The problem - if there is ever a flash fire inside the dryer, it's now shooting into the room instead of outside - so that is probably where code comes in. I accept this trade off and only use the dryer while I'm awake and also make sure the batteries in the smoke detector are good.
  7. Doing The Dixie Eyed Hustle

    Doing The Dixie Eyed Hustle Minister of Fire

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  8. HumaneSocietySteve

    HumaneSocietySteve New Member

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    Hello Everyone,

    These are some great suggestions. To address the safety issues brought up. My dryer is electric so no worries about gas exhaust. I only run the dryer when I am home and never when I am sleeping. As far as I know we don't have any dryer vent police in my county so not worried about codes.

    While reading your suggestions I had an idea that I think I will try so please feel free to respond with your ideas on design and I will let everyone know how it works when completed.

    My idea is to take a square plastic 4 gallon bucket like the ones cat litter comes in, of which I have a few being in the humane society. I would cut round holes in opposite sides to fit the dryer vent hose. The hose would vent warm dryer air into one side of the bucket which would be filled half way with water. The air would circulate through the void in the bucket dropping the lint into the water. I would place a piece of nylon screen like the kind used in a screen door on the exhaust hole on the other side of the bucket to catch any lint not trapped by the water. I would attach whatever length of vent hose to the exhaust side of the bucket trap to vent warm air into the adjoining living space or directly into the HVAC return which conveniently sits right next to my laundry room. The second option would allow me to turn on the HVAC fan and circulate the warm air throughout the house.
  9. Corey

    Corey Minister of Fire

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    Steve - that might work, though the couple of 'water filters' I've seen really didn't work for catching the small lint. Maybe the surface tension of the water, the fact that the dryer air doesn't really 'mix' with the water, I don't know - but they wound up letting lint sneak out. Plus, don't forget, there is already a screen in the dryer to catch a lot of lint, so what ever comes through the hose will be smaller than can be caught on most screens. Then you've also got the hassle of periodically filling, cleaning, and emptying the water, etc.

    With the HEPA filter, I basically hook the box up when the first chills of the season set in - around mid October for me - and forget about it until the next spring. So far, I ran one filter for 2 years, took it apart and blew the accumulated lint off, ran it for another year, then bought a $5 replacement filter and it's currently in it's 3rd year of service - so that works out to some pretty cheap heat recovery!
  10. madrone

    madrone Minister of Fire

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    I've puzzled over this one too. If you use some kind of exchanger, you will get condensation in the duct. If you vent into the room, you'll get a lot of humidity. Think about how much water is in the clothes. Even with my front-loader it's a lot. The lint seems like less of an issue, but I suppose that's a regional thing. We're fighting mold year-round here in Western Oregon, so I'd probably not vent into living space. Those in dryer climates will worry more about lint. An exchanger that collects condensation and pipes it to the drain seems best, but I haven't been able to come up with anything yet.
  11. HumaneSocietySteve

    HumaneSocietySteve New Member

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    Hey Madrone,

    I am thinking that the extra humidity will be a good thing here in East Tennessee. Many people run humidifiers to offset the low humidity we have in the Winter months. I keep water on the wood stove when it's going and that doesn't do much to raise the humidity. Once I start using whatever gizmo I come up with I will let you know how the humidity issue plays out.

    One idea I have contemplated is to use some sort of humidity level hydro-stat that would automatically divert the heated dryer air into the house when the dryer air reaches a level deemed appropriate. This would involve designing a unit that could mechanically divert the air when the hydro-stat reaches the preset humidity level. Sadly this level of technology is above my ability to design/build. Anyone else see a challenge with the appropriate skill level go for it....Just share it with us technologically/mechanically challenged guys.
  12. pdboilermaker

    pdboilermaker New Member

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    http://www.amazon.com/Dundas-Jafine-CHK100ZW-Heat-Keeper/dp/B00004YWK2/ref=pd_bxgy_hi_img_c

    I use this little gem on my dryer and have for years, the condensation issue isnt too bad because it is close to a cold air return so the cold air returns sucks the moister out of the utility room and spreads it through the house.

    I was more interested in the humidity in the winter than the little heat it provides but, you keep the point

    Oh yeah, bought mine at Menards
  13. Jay H

    Jay H New Member

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    I do the same thing, and when I run out of (dry) underwear, I just hang some above the stove when it's running, it's dry in like no time!

    Jay
  14. Valhalla

    Valhalla Minister of Fire

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    We use the automatic outside valve to shut down any air loss when the dryer stops. I do not want the humid air in my basement.

    It seals very nicely on shut-down.
  15. Jay H

    Jay H New Member

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    Something similar to an automatic damper flue on a gas boiler? My wells-McClane gas boiler (my backup source of heat at my home) has one of those automatic damper flue that closes when the flue isn't exhausting the gas fumes (has a backup sensor to shut the furnace off if the damper is malfunctioning of course. It keeps the heat in when the fumes aren't in need of being vented..

    Jay
  16. rhetoric

    rhetoric Member

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    I live to be in violation of code NFPA 211! Muuhhhhaaahaaa.

    I have one of those cheapo plastic diverters. Works great. Does blow some lint into the house, despite the screen. I've thought about putting a big pair of nylons around the opening to catch the finer stuff. But it's a lot of expensive energy going outside w/o it.
  17. Redox

    Redox Minister of Fire

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    I've disconnected the vent on our dryer on occasion to see what would happen. Forgetting about the lint and the possible fire hazard, there seems to be just too much humidity, too fast. The walls start sweating and by the next day, the humidifier is back on. I've thought about a heat pump like device for heat recovery, but the economics just aren't there quite yet. I've lived with an unvented dryer before and it sucks more than it saves, IMHO.

    Chris
  18. Titus

    Titus New Member

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    It does not help in your desire to convert what you already have but....

    There are dryers designed to exhaust indoors, called condensing ventless dryers. I have been doing some research , and this is the type I will be buying to replace my 16-year old electric dryer. In the condensing dryer, the hot air in the clothes drum cycles though a closed loop. Moist hot air passes through a condenser which removes the water. Hot dry air then returns to pass through the clothes again. The moisture is collected in a bin or pumped out to the same drain the washer uses. Some devices use a loop of cool room air to chill the condenser. In some models, particularly the wash/dry combo machines, cold water is used to chill the condenser. In either case, there is no vent and no lint blown into the room. The waste heat end up in the laundry room. This would not be good for areas where cooling is the greatest utility cost, but up here in Maine, I'd rather have the heat stay in my house. The two months a year I would get a hot laundry room aren't a big deal.

    These are mainly European designs. I haven't seen them in the appliance store, but they can be ordered. They are made by such companies as Bosch, LG, Eurotech, Equator and Miele.

    Costs appear to be in the range of the expensive dryers that match the new front load washers.

    Here is one by Bosch...
    http://www.ajmadison.com/cgi-bin/aj...=Google Products-_-00271-_-Bosch-_-WTE86300US

    I am seriously considering a combo unit since my washer is old too. An LG example...
    http://www.newegg.com/Product/Product.aspx?Item=N82E16896140060

    Thor Appliances makes and sells such machines.
    http://www.thorappliances.com/
  19. myzamboni

    myzamboni Minister of Fire

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    A friend of mine had (not the past tense) one of these and his better half forgot to pay attention to the fact you need to keep water in the resovoir to trap lint. He came home from work while she was out running errands and there was a light blue 'snowstorm' thoughout the house (denim load).
  20. mikeathens

    mikeathens New Member

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    I have two kids and thought this might be a good humidity booster, too. Did some research and decided against it due not only to the additional particulates, but also the VOCs that come off of many types of synthetic fabrics, detergents, and fabric softeners (if you're not using vegetable-based cleaners). Some people may not give a rat's ass about that type of thing, but most indoor air quailty sucks enough without intentionally diverting even more pollutants into the house.
  21. HumaneSocietySteve

    HumaneSocietySteve New Member

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    Hey Guys,

    All very good points. Thanks for all the input.

    I think I have decided to build a 3' square box out of aluminum (to avoid rust) which I will add two 16" x 20" HEPA filters to allow filtered outward heated airflow. I will locate this in my basement and divert the dryer vent to this box. I am hoping the aluminum box will contain any lint that gets by the dryer filter (which I am religious about cleaning after each load) and allow heat and moisture from the dryer to infiltrate my basement. I am hoping the heat will migrate into the above living space (heat rises) and the moisture will be captured by the two dehumidifiers that don't have much to do in the winter anyway. I plan on monitoring the moisture closely to see if there are any adverse effects and I will clean the lint from the box with my shop vac as needed. Any thoughts???
  22. Redox

    Redox Minister of Fire

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    Just check it regularly to make sure you don't start a mold farm in the filter. If you put a small circulating fan near it to keep the humidity moving, I don't think you will have a problem.

    Chris
  23. dbjc364

    dbjc364 New Member

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    parents put panty hose over the dryer vent- my man is doing that today- and plug up the hole till spring-then we'll stick it back outside
  24. Gooserider

    Gooserider Mod Emeritus

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    Another option that I've seen mentioned in other threads which seems like a possible aid would be to get an outside air feed to the dryer - the idea being to keep from sucking in heated air and blowing it outside with the water vapor.

    It wouldn't recover any heat, but might keep the loss down... (or even be a way to bring in fresh heated air.)

    Gooserider
  25. Redox

    Redox Minister of Fire

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    Hmm. What if I put the dryer outside and piped the air INTO the house? ;-)

    Just kidding. It would be a bear to have to take the laundry out to the dryer...

    Chris
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