# Wood boilers and clothes dryer? what do you know



## MS-310 (Oct 2, 2006)

Wood boilers and clothes dryer?

I would like to know what you have maybe seen or done to make your boiler dry your clothes in the clothes dryer.
I have been asked this alot and I have tore my old clothes dryer down and going to retro fit it maybe wiht my own Idea, if you got some tell me.
Do you know if 180 deg. air wood dry your clothes fast or slow or the same as the dryer. 

Thanks guys


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## omegajim (Oct 2, 2006)

*air temp*

I guess I would put a metal meat thermometer in either the dryer or place the thermometer at the exhaust. I would imagine the exhaust would be 10 - 15 degrees cooler than the air being blown into the dryer. 

It would certainly keep the house humidified. That's if you don't mind condensation on the windows. Also, remember it will take a fair amount of heat to dry the clothes. A valve of some sort would be required to force the heat to the dryer (as opposed to heating your house). This is all being based off of the fact that you have a wood furnace. If not, it would seem to be a little more trouble than it's worth.

Good luck.


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## MS-310 (Oct 2, 2006)

omegajim said:


> I guess I would put a metal meat thermometer in either the dryer or place the thermometer at the exhaust. I would imagine the exhaust would be 10 - 15 degrees cooler than the air being blown into the dryer.
> 
> It would certainly keep the house humidified. That's if you don't mind condensation on the windows. Also, remember it will take a fair amount of heat to dry the clothes. A valve of some sort would be required to force the heat to the dryer (as opposed to heating your house). This is all being based off of the fact that you have a wood furnace. If not, it would seem to be a little more trouble than it's worth.
> 
> Good luck.




I would vent the dryer the same way as it vents now so it wouldnt have any problems with condensation.
thanks jack


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## laynes69 (Oct 2, 2006)

I was on a web site somewhere and a man had a laser heat gun. He took the internal temp of the dryer and said it was 120 to 130 degrees. With this in mind I think its possible to make a setup to dry clothes. I wish I knew where I seen it, but the temp range sounds right. That would be nice to heat the home, hot water, and dry clothes. It would save alot of $$$$.


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## MS-310 (Oct 2, 2006)

I think it would be alsome to hook it up so you could still use the dryer the same way as before you put a small heat exchanger in it for summer time, Im tareing my old one down this week and going to make some thing work


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## laynes69 (Oct 2, 2006)

Replace the heating elements with a radiator. The drying time may be a little longer, but you would have no risk of a fire. Also part of the hot air could be used to help heat the room. This is where creativity would come into play.


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## MS-310 (Oct 2, 2006)

We will just see


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## smithm (Oct 3, 2006)

*Drying clothes*

Please keep us posted when and if you get it figured out. I would like to tear into my dryer also, but do not have the time right now. I did talk with a guy last month that had his dryer working with a heat exchanger. He said it worked great until the exchanger vibrated loose. He has not done anything since then. He was located somewhere south of Grand Rapids.

Mike


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## John Paul Sanborn (Oct 4, 2006)

I've thought of this too, but do not have the equipment, wood heater to start the list with.

I would put the heat exchanger of the wall with an intake duct around it and an air filter. I would think around a dryer lint buildup on the exchanger will be a regular maintinace issue.


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## stumpguy (Oct 4, 2006)

you might be able to use an automotive heater core for the heat exchanger. a small one would be about the size of the dryer heater element..


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## MS-310 (Oct 4, 2006)

I was thinking of a heater core, I mite just try it. You would have to some how unplug the elec heater in the dryer then maybe put a aqustat some where or a some thing to control the heat.... I dont know but soon I will have my dryer working with my boiler. Its going to be a rigg job for the first time but I would like to make a kit or some thing.


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## windthrown (Oct 4, 2006)

*OWB dryer*

Hmmm, it wood seem that a water to air HX wood work, but it wood need to be a small one for an appliance. Put a squirrel cage fan on it and blow the heated air into the dryer drum, and vent it out the back. If your boiler temp is set to 180 you should be able to get some good heating out of it. 

Maybe I will get an old electric dryer from the dump with a burned out heating element. Then add a small heat exchanger to my OWB water heat loop and see what kind of air temp I can get from it. Might be worth a try. :monkey: 

You can use a water-water HX for a hit tub too. I refrained, as you need a lot of bypass plumbing to be able to shock the tub (flat plate HXs do not do well with the high amount of chemicals in a tub, especially during a shock treatment).


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## stumpguy (Oct 4, 2006)

i don't see the need for an aquastat. i would think you'd need all the heat you can make. the electric heating coil in a dryer glows red while in use.


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## windthrown (Oct 4, 2006)

*Aquastat*

Too much heat is not always a good thing... you need the aquastat to keep the boiler from boiling over. Most of the OWBs will allow for 190 as the max temp. You would have to go to a steam boiler to get above 220. Steam is trickey to work with. 

Which may be why there are not any dryer hookups that I am aware of from any OWB manufactures. But still, so what if it takes 2x or even 3x the time to dry your laundry in an OWB fired dryer? It is 'free' heat. :sword:


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## MS-310 (Oct 5, 2006)

windthrown said:


> Too much heat is not always a good thing... you need the aquastat to keep the boiler from boiling over. Most of the OWBs will allow for 190 as the max temp. You would have to go to a steam boiler to get above 220. Steam is trickey to work with.
> 
> Which may be why there are not any dryer hookups that I am aware of from any OWB manufactures. But still, so what if it takes 2x or even 3x the time to dry your laundry in an OWB fired dryer? It is 'free' heat. :sword:



The temp in the dryer is about 140 deg.
So if I get it to 180 it should rock and roll..... Still trying to get time to do it.

God if it didnt smoke so much I would have done it by now. lol


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## windthrown (Oct 5, 2006)

*OWB driven clothes dryer*

 With all that OWB smoke in your eyes all the time, it is no wonder that you can even post messages on the internet. Must be awful! And all the smoke in the dryer that the OWB will produce. Smellyclothes... 

Imagine how much better it would be if you had a woodburning stove in the basement that you could just string a clothesline around? :biggrinbounce2: 

On a more serious note... for the OWB dryer, with the boiler temp at 180 you would get about 160 out of a HX connected to any device. Rule of thumb, you will get about a 20 degree drop in temp across a HX. 160 should still rock though, if all you need is 140.


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## cord arrow (Oct 6, 2006)

betcha spike would weld something up for you, in his state-of-the-art-non-polluting-welding-facility....


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## Rspike (Oct 6, 2006)

cord arrow said:


> betcha spike would weld something up for you, in his state-of-the-art-non-polluting-welding-facility....


:hmm3grin2orange: :sword:


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## RaisedByWolves (Oct 7, 2006)

Im seriously questioning wether you are going to be able to get a big enough heat exchanger inside the dryer to pull this off.



The elements in an electric dryer are probably somewhere in the neighborhood of 1200 degrees and have a large volume of air blowing over them.



Its going to be very hard to get a suficient volume of air to the correct temperature to make this work.


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## tawilson (Oct 7, 2006)

Can't you just attach it over the intake for the dryer? Then run the power from the heating elements to a circ pump?


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## hamradio (Oct 7, 2006)

I'm very interested in waste oil boilers. I've converted a home fuel oil burner to run on used motor oil, tranny fluid, hyd. fluid, etc. On a waste oil burner yahoo group, someone showed how they tied their drier into their hot water boiler. They put a ton of that finned baseboard heat stuff in it. Like 21 feet total, or something like that. Apparantly, it worked. My thought is, that if you were to do it, you could wire it up with a solenoid, so you wouldn't be wasting heat when you weren't drying clothes. Maybe a 110 volt solenoid that can handle the temp, that is in line with the motor on the dryer. When the dryer is on, the hot water is on to the dryer.


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## Kneejerk Bombas (Oct 7, 2006)

A few years back I switched from an electric to a gas clothes dryer. A big difference I noticed was the volume of air the gas dryer moved compared to the electric. The gas dryers are said to be more efficient, but I wonder if the volume of heated or cooled air pulled out of the house is factored into the efficiency equation. The gas dryer moves about 5 times as much air.
Figuring out the optimal amount of air moved might be tricky.
If you need a bigger heat exchanger, you could just replace the back of the dryer with the exchanger, after all, all the air does enter through the back


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## tawilson (Oct 7, 2006)

I should have said take one of the leads from the electric element and use to run a circ pump, as the element is 220v. I'm sure the tsat in the dryer will not be satisfied using a hw coil, so the pump should run when the dryer does, cept' during the cool down cycle. If it does happen to reach the cut off temp, the pump will stop. This is all theory, of course.
I like Mike's idea, screw a car radiator to the back of the dryer and trim it out nice.


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## windthrown (Oct 7, 2006)

*It should work tho...*

I do not see why a HX that can heat a garage (2x2 ft) cannot be used to heat a clothes dryer. Use a larger fan and blow more air through the duct. So what if it takes longer to dry your clothes? Call it a "gentle heat dryer"
as a marketing plug and charge people 2x the price vs a standard dryer. 

As for gas vs electric, a gas dryers will usually pay for the higher purchase cost vs electric in less than a year. Gas is far more efficient. It blows more air becasue it has to vent the gas fumes as well as heat. I am not sure how much more air a gas dryer blows out of the house though. Maybe an issue, but if you are burning wood in an OWB for free like we are, it does not really matter.


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## MS-310 (Oct 9, 2006)

RaisedByWolves said:


> Im seriously questioning wether you are going to be able to get a big enough heat exchanger inside the dryer to pull this off.
> 
> 
> 
> ...



Maybe true, but im sure as heck going to try this. One thing is how many BTU's does it take to do this? If that little element only puts of like only 20,000 btus I could do this.

Thanks for the input on this guys.


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## MS-310 (Oct 9, 2006)

windthrown said:


> With all that OWB smoke in your eyes all the time, it is no wonder that you can even post messages on the internet. Must be awful! And all the smoke in the dryer that the OWB will produce. Smellyclothes...
> 
> Imagine how much better it would be if you had a woodburning stove in the basement that you could just string a clothesline around? :biggrinbounce2:
> 
> On a more serious note... for the OWB dryer, with the boiler temp at 180 you would get about 160 out of a HX connected to any device. Rule of thumb, you will get about a 20 degree drop in temp across a HX. 160 should still rock though, if all you need is 140.



cord arrow,

Do you really think he would do this for me..........:monkey: 

I cant wait to see how much ever one gets pissed on the other thread about the smoke, I called CB and they gave me some really good info on OWB and Indoor stoves, got to love it.

I would wounder if people would buy a dryer for there owb??????
I wouldnt but maybe some would. THanks guys for the Help


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## windthrown (Oct 9, 2006)

*I wood buy one!*

Hey, we removed $200 a month from our electric bill by intalling the handy dandy OWB here. We do not have NG here, and LP is really pricey. Biggest energy use here is space heating, then water heating. We nuked those two. Next is the hot tub, and then the clothes dryer. The hot tub is too complicated to heat with OWB; possible with a flat plate HX, but you need a complete bypass plumbed circuit to bypass the HX during shock treatment. 

I would use an OWB fired dryer :rockn: for sure. We have a strange utility room here anyway with lots of space. We have a std pair of washers/dryer for the clothes, and my girlfriend has a separate washer for cleaning fleece (alpaca and sheep wool; she raises those animals here).


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## MS-310 (Oct 9, 2006)

windthrown said:


> Hey, we removed $200 a month from our electric bill by intalling the handy dandy OWB here. We do not have NG here, and LP is really pricey. Biggest energy use here is space heating, then water heating. We nuked those two. Next is the hot tub, and then the clothes dryer. The hot tub is too complicated to heat with OWB; possible with a flat plate HX, but you need a complete bypass plumbed circuit to bypass the HX during shock treatment.
> 
> I would use an OWB fired dryer :rockn: for sure. We have a strange utility room here anyway with lots of space. We have a std pair of washers/dryer for the clothes, and my girlfriend has a separate washer for cleaning fleece (alpaca and sheep wool; she raises those animals here).



The hot tub is very easy to hook up, well worth it, ask your CB dealer for there Technical Illustration Manual it shows you ever thing.

Jack


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## RaisedByWolves (Oct 9, 2006)

windthrown said:


> I do not see why a HX that can heat a garage (2x2 ft) cannot be used to heat a clothes dryer. Use a larger fan and blow more air through the duct. So what if it takes longer to dry your clothes? Call it a "gentle heat dryer".





Generally its easier to heat cold air than it is to heat hot air. This plus your not pulling fresh air into the garage are working in your favor in this scenerio(heating the garage).

Once the air passes over the HX in your dryer App, it doesent get a chance to go round again. It would seem to me that you would need several layers of heat exchangers to get your air temp up to what you are hoping. 

Either this or slow down the airflow to near nothing, and then the electricity of tumbling the clothes for hours is going to outweigh the benefit of this setup.


Im of the opinion that the air entering the normal dryer is hotter than you might expect.


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## ktm rider (Oct 22, 2006)

I have looked into using the boiler to dry clothes also. I have found the heat exchanger that is specifically made for doing this on this site.

http://us.outdoorfurnaces.com/comersus/store/comersus_searchItem.asp

Other than that I have not been able to find any technical info on how to do this at all. I sure would like to know. with 3 kids our electric dryer runs non stop. !!! if you find out please post it... Thanks.


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## BigSpud (Oct 27, 2006)

ktm rider said:


> I have looked into using the boiler to dry clothes also. I have found the heat exchanger that is specifically made for doing this on this site.
> 
> http://us.outdoorfurnaces.com/comersus/store/comersus_searchItem.asp
> 
> Other than that I have not been able to find any technical info on how to do this at all. I sure would like to know. with 3 kids our electric dryer runs non stop. !!! if you find out please post it... Thanks.



That link is only partial. The full link is http://us.outdoorfurnaces.com/comersus/store/comersus_viewItem.asp?idProduct=22

I am trying to figure this out myself. I just installed a Central Boiler unit and put in a takeoff for a circulator pump for my electric dryer. I have not looked into the dryer itself, but based on my experience with a Modine heater that is installed in my basement, I would guess the air will be a little cooler from the wood boiler HX than directly from the electric heating element.

The 12x12 unit in the link would have to be built into a box that takes room air and ducts it after the HX into the intake of the dryer. That is my big question right now -- does the dryer have a nice "intake"? I don't want to add a fan to the HX box, but let the dryer draw it in.

Good point was mentioned about vibration. That would be a killer for a copper connection I think. 

Next week's project is to take the dryer apart and see what it looks like. I will post back the results.

Spud


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## lapeer20m (Sep 22, 2014)

I am reviving this necro thread....

How come it's 2014, and nobody has posted photos and or video's of their dryer converted to use hot water instead of electricity? Does it work so terribly that nobody has been successful? This really does not seem like rocket science. 

I've reduced our electric bill to just under $50.00/month. My guess is that the washer and dryer account for more than 50% of our current (pun intended) electricity usage so i want to convert my dryer. Unfortunately, i have an unusual dryer. It's a Swedish made Asko brand. I'm going to look at how it is constructed and see if i can come up with a plan. I kind of wish i had a more standard type of maytag or whirlpool dryer so i could easily find a junk one to experiment with. The Asko is smaller than a standard american dryer and is squeezed into a tight space. The neat thing is that it only takes 34 minutes to wash a load of laundry on the quickest setting, and it takes less than that to dry with electricity. Even if i doubled the drying time with hot water i would assume that this would still save a bundle of electricity. 

I have a full size truck radiator, and i also have a couple of random automotive heater cores laying around. When i finally come up with a good plan i will start my own thread complete with photos.


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## hupte (Sep 22, 2014)

i plumbed in a dryer that runs off my owb. i've been using it for about 4 years now. it works great. when the water is really hot (180*F) it dries my clothes 5-10 min faster than my gas dryer. when the water is cooler (140*F) it takes about 20-25 min longer than the gas dryer to dry my clothes. but it also depends on the dryer capacity, hx and fan cfm. i'm using an old electric dryer that i removed the heating element from. fortunately the dryer had a wiring schematic inside of it. so it took me about 4 days of messing around with and almost completely rewiring the whole thing, to get it working properly. it would have taken less time but i tried to run it without an additional fan behind the 12"x12" water to air hx, to make it work. i also had to change it from a 220v dryer to a 110v. it wasnt that hard since the heating element was on one hot leg of the 220. and the rest of the dryer, the motor that turns the drum and the dials, were on the other hot leg of the 220. it sounds like it would be very difficult to make a functional dryer that ran off gas or electric in the summer, and off the owb in the winter. that seems like too much complexity in one unit. after adding up all the costs i spent about $300 on my dryer. then found out a couple months later there is a company or companies, that make and sell dryers that run off a boiler. for around 400. but that was a few years back. prices may have changed by now.

i still use electricity to turn the drum and run the fan but all the heat comes from the owb.


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## Sawyer Rob (Sep 22, 2014)

* I've seen dryers hooked to a wood boiler... The guys put a small heat exchanger in place of the burner...

Here's what I did with a dryer I hooked to my wood furnace,







SR*


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## zogger (Sep 23, 2014)

Our dryer broke a few years back. We already had an outside clothesline..so..just kept using that. Ya, some days can't hang anything out, meh, it gets done eventually.


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## lapeer20m (Sep 23, 2014)

I took a look inside my dryer today. I had a difficult time understanding what path the cold air takes on it's way to the heating coil. Since there are no other vent holes air must enter through the front panel. 

Ultimately the air is heated by electric coils on the back panel of the machine. 

I think I can easily modify the air flow to first pass through a radiator on its way to the electric coils. There is space behind or under the dryer. 

I have a few other more critical projects to finish first. But when I begin the modification I will make it's own thread with step by step photos.


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## KenJax Tree (Sep 23, 2014)

zogger said:


> Our dryer broke a few years back. We already had an outside clothesline..so..just kept using that. Ya, some days can't hang anything out, meh, it gets done eventually.


Air dried undies are very comfortable


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## taskswap (Sep 23, 2014)

Wow... this is a really interesting idea. Drying clothes is a big energy suck and it's all wasted heat. I considered one time trying to recapture it, but not just trying to produce that heat more cheaply. All clothes dryers are either gas or electric and we don't have gas here so electric it is - our most expensive option...

I think if I was going to give this a shot I wouldn't be doing it with direct plumbing. But a dryer basically just has a heating element inside a duct, basically just a short box. I would imagine a small heat exchanger on eBay would be easy to find. I would think something like a 7-row transmission oil cooler would be a perfect option. You could just pull the dryer away from the wall, and make the airbox a bit larger to put the unit in there - it's on the back on mine, anyway.

In fact I'm willing to bet you wouldn't even really need to modify the dryer's controls - just work out some way to get the flow going through the heat exchanger. It's basically a simple thermostat that kicks on whenever the air temp is too low, so as long as you keep the air temp up it will automatically keep the heater element off, but the dryer will still work as normal. It'll just think it was doing a really good job.  But during the summer when you weren't burning, it would just use its own heater.

I'm thinking of moving the laundry room to an area behind our master bath and the wife wants radiant floor in there. Maybe I'll add a tap for it. Radiant flooring uses a lower temp anyway so you could kill two birds with one stone.

Has anybody done this? It seems like such a perfect opportunity...


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## taskswap (Sep 23, 2014)

MS-310 said:


> Maybe true, but im sure as heck going to try this. One thing is how many BTU's does it take to do this? If that little element only puts of like only 20,000 btus I could do this.



My dryer (a Kenmore) is on a 240V 30A breaker but only draws 22. Figure 90%+ of that is the heating element - my motor is only 1/4hp. That's only 18000 BTUs for my unit. Yours might be larger, but either way, the math seems to prove this out.

This is such an awesome idea I want to run home and tear apart my dryer. Very interested in your choice of HX. I personally think I'll try the oil cooler - they're compact, pressure tested to high levels and they can take all kinds of abuse. And they're super cheap on eBay because people are always adding them to cars to help their towing capacity (or replacing blown units).

We do a load of laundry every day - sometimes two. No kidding, with five kids, we're lucky it's that few. I'm kicking myself for not thinking of this sooner.


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## lapeer20m (Sep 23, 2014)

The sticker in my dryer claims 2,700 watts. That's less than 10k btu



taskswap said:


> In fact I'm willing to bet you wouldn't even really need to modify the dryer's controls -..



I agree. I am pretty sure most dryers have a "no heat" option. Otherwise, it would be easy enough to wire in a switch or a single breaker one could easily flip that would disconnect one of the 120 volt legs. American dryers tend to have all the controls and the motor operate on 110 volts......240 only goes to the heating coil. On a gas dryer, an even easier solution is to simply turn the gas valve off in the winter. I am assuming most would want to use the dryer all winter using only owb heat, and revert the dryer back to normal operation in the summer months.

I already recover most of the heat as i vent my dryer into my house during the cold months.

The plumbing for this modification will be simple for me as the dryer sits just above my boiler room. My plan is to incorporate the dryer into the owb circuit before it reaches the main plate heat exchanger. This way the water is the hottest, and any heat "loss" will filter into the hallway. Our laundry is in the main part of our house.


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## GF#2 (Sep 23, 2014)

I joined arborist site a few weeks ago looking for info on this very subject. I have heated my house and hot water with a home made owb for about 15 years and heating the cloths dryer with it has been on my mind for a while. When i built my owb i had never seen or heard of them before (i thought i had come up with the next big thing. lol) so nothing was really done to be permanent because i wasn't sure how well it would work. So 15 years later i am in the final stages of a major overhaul and heating the cloths dry is something i have added. Basically i have ducted the air inlet for the dryer the same way the outlet is ducted. The air inlet duct runs up to an 8"x8" heat exchanger mounted to the wall above the dryer. And with some rewiring and changes to the controls i will be able to select the heat source. Either electric or the owb. I'm still a couple of week out from being able to test it my main focus right now is getting the heat back online as the owb is my only source and winter appears to be coming on fast.


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## Bill G (Nov 22, 2016)

Digging up an old thread to see how successful folks have been


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## GF#2 (Nov 22, 2016)

I was unable to make it work effectively with the electric heating elements still in the dryer. So i can not select between electric and owb to dry clothes as I mentioned i was trying to do in my last post. However we have been drying clothes without the electric heating elements solely on the owb for two years. It takes about twice as long to dry a load as it did with the electric but it works. I have four small children so my wife washes and dries at least two loads a day. When i put the dryer on the owb the power bill went down about $25 a month.


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## Del_ (Nov 22, 2016)

We have a semi heated porch and hang cloths to dry all year. Some things are dried hanging near the wood stove if needed soon. Boots near the stove. Hardly ever use the dryer, summer or winter. Just don't need it.


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## Bill G (Nov 22, 2016)

GF#2 said:


> I was unable to make it work effectively with the electric heating elements still in the dryer. So i can not select between electric and owb to dry clothes as I mentioned i was trying to do in my last post. However we have been drying clothes without the electric heating elements solely on the owb for two years. It takes about twice as long to dry a load as it did with the electric but it works. I have four small children so my wife washes and dries at least two loads a day. When i put the dryer on the owb the power bill went down about $25 a month.



Wait until those 4 small children become 4 big children. Two loads a day ha As for using it in the summer how hot does the room get


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## GF#2 (Nov 22, 2016)

There is no change in the room temp it stays the same temp as the rest of the house. It works the same as it did on electric it just pulls air through a water to air heat exchanger instead of the electric heating elements then vents to the outside.


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