Using attic heat to dry clothes and help cool the house
 

I got up in the attic the other day . Measured it was a blazing 134 degrees. It got me thinkin being i dont have a dryer .Noticed Xringer uses it to heat his basement durin the winter. I thought about utilizing the heat built up up there . Run it somehow to the dryer along with the solar air heater i have just blowing heat out every day . Anyone know if that would be feasable. And even to help take a little bit of the cooling load. A

One issue would be dust and fiberglass fibers etc getting into the clothes. Adding more venting to the soffits is one of many things on the list...

Ive got the blow in insulation . Cellulose . I dont think it has fiberglass . But i know dust would probably be an issue . Would have to have some sort of active dust filter for sure . Far as ventalation . My house is one of those old ones . I have a 4 foot by 3 foot big vent on the side

Yup our house has those on the E W and S sides. They will get covered up when I get around to putting in more soffit vents.

I like cellulose insulation but it is extremely dusty. Also the other thing to think about is that it's treated with borates which kill bugs and acts as the fire retardant. Wouldn't want that in my clothes. Though some sort of heat exchanger could be done. Use a metal pipe to duct the air through in the attic. It will absorb quite a bit of heat.
Have run copper hvac line in many houses in the summer and it will get hot enough to burn skin in minutes of being in the attic here.

This is a really good idea. I have been thinking about how to utilize excess heat from my attic system in the cooling season:http://ecorenovator.org/forum/solar-...bottom-up.html

I've measured the temperature up there and it has already gotten to a peak of 137 F! I've considered for a long time using it to heat water but it seems like more work than it's worth. I even have it plumbed with ducting and a 200 cfm fan that I originally planned for that. But I decided after careful thought that just using net metered PV was a better solution for my electric water heater. Much less stuff to break and leave me taking cold showers.

I think the trick to making this work would be if you could find an electric dryer with a makeup air connection. If they are made (I don't know if they are)then you could kill two birds with one stone. You wouldn't be replacing conditioned air with outside air and you would get a free source of hot air. Just put the dryer in Tumble Only mode with no electric heat whenever you have excess attic heat and you want to dry your clothes while simultaneously cooling the attic.

Anyone know of any dryers with a makeup air connection?

BTW, if you have an electrical diagram of your existing dryer, and are handy both in electrical and structural subjects, then you could kill three birds with one stone. My kind of stone. First you would wire the dryer blower with an additional manual mode switch isolated from all other functions of the dryer. This would require knowing how to modify it electrically so the power going into that blower does not backfeed into other dryer electrical systems. It might require either diodes or a multiple pole switch that turned off normal power to the dryer while applying power only to the blower.

Second, it might be possible to modify your existing dryer so there is duct connection that bypasses the normal intake vent.

If you did these two things then you wouldn't even need a separate blower.

1. You could use the dryer blower manually just to cool the attic. Hot air would run through the dryer but be unused to dry clothes.

2. You could use it to dry clothes when the attic is hot.

3. No external blower or wiring to it would be required. Just install the ducting. Cheap and simple. My kind of plan.


Edit: Did some research and it really isn't feasible to modify a dryer for makeup air. They just aren't air tight. It makes much more sense to air seal the laundry room and then run a makeup air duct to the ceiling of it from the attic. It could be as simple as replacing louvered doors with solid doors and putting a door wiper seal on the bottom of the doors. If you have a dedicated (small) laundry room then this is definitely the easiest way.

My laundry room at the moment is quite small . I dont have a dryer right now . All i have is a washer . I use the clothes line to dry clothes never have cared for spending extra money when i could get it free from sun. Ive been thinking on it mainly trying to figure out what would be best to do with that buildup of excess heat. Afterthinking about it and all the dust. Its always dusty . Then with the extra air flow. It would need a filter and im not home most of the time to be able to monitor . It would leave me in a pickle. So im thinking of just ditching that idea and going only to a solar air panel . Prob be a lot cleaner.

Using attic heat for your dryer has already been done by at last one person:

Converting a Clothes Dryer to Use Solar Heated Attic Air For Drying

IMO dust isn't even an issue. I have had my attic fans going for a few years now and I have cellulose insulation. My outlet vent in the kitchen has virtually no dust build up on it. The fans in the attic are just as clean as my fans I use year round in the house.

Thats a good link . Ill check into that. I just put in the insulation a couple months ago . When i shine my laser up there you can see the line its so dusty . Maybe still seddling ? I wouldnt think

I read that article in the link you posted, Daox. Good article. It sounds like it's possible to air seal a dryer after a fashion but not perfectly and since it's not insulated the dryer still radiates heat. He also found that the dryer blower wasn't sufficient alone with a 6 inch duct from the attic. That was good to know.

I think I'll try to stick with the idea of isolating the room, rather than the dryer. I had been planning on pumping in cellulose in the walls of the laundry room just to quiet it down. Now there's another reason to do it. It looks like I'll be modifying my system (yet again:( ) with a 12" branch duct from the main duct from the attic to the laundry room ceiling. I'll have to do some thinking whether I can get away with a makeup air damper in that line or whether I will have to use an actively controlled damper to stop interaction with the makeup air dampers for the whole house fans?? I might be able to get away with a makeup air damper if I can get a tight fit on the door to the laundry room.

I did a mental simulation of using a dedicated isolated laundry room with warm incoming air to the whole room used for the dryer. It won't work as I was thinking. When a person would open the laundry room door up to a 135 F or more heat would hit you and would then start spreading throughout the house. That would completely negate the idea of isolating the house from excess heat in warmer months. You could get around it at the expense of much complexity, including running the dryer fan for 10 minutes or so after the load is dry, while closing the (now actively operated) ceiling vent. My experience is that added layer of complexity would completely negate the original advantages of having an isolated laundry room.

It seems the choice is either using one of the methods in Daox's link or nothing. Just would have to use a bigger duct so one could get away without a separate blower.

Just put in an airlock.

I hope you're kidding. In fact I'm counting on it.

Ive found instead of running ducts . Buying a few sheets of cheap plywood and some insulation is cheaper and bigger.

That's sounds like a good idea. However, you will still need a damper of some sort either manual or a back draft damper, like in a bathroom. The problem is the cheap backdraft dampers are all round and also require that they are not turned upside down (sideways is OK also). It might be better to have a round duct in the attic with an elbow to it so you can install a backdraft damper sideways. Then run a square plywood duct in the laundry room to the dryer.

I actually like the idea of a square roughed-in duct in the laundry room. It won't have the mickey mouse look to it of an exposed round duct.;)

I was going to put a small piece of some sorta plastic in there with a hinge on top and at bottom a stiff piece of plastic or something and under it a 2x4. So the air could only flow out the vent and not backflow. Kinda like a 1 way valve for air duct but poor mans way.

Have you done anything with this?

I hung a clothesline in the attic. It works perfect. I hang clothes in the morning while the attic is cool.

That's sounds like a great idea. One thing that might be a problem is trying to use that method in winter. I think most people would have a hard time getting around using a downstairs dryer of some sort in winter. The thing I liked about Nokia's idea was that it eliminates using the downstairs conditioned air as the makeup air for the dryer. That's important in both winter and summer. You can use the heat up in the attic for the downstairs dryer in spring, summer, and fall and you can also avoid exhausting conditioned house air in winter, spring, summer, and fall with that method.

I'm still working on the design stage using a lot of Nokia's ideas. I'll get to actually implementing it eventually. I've got just too much on my plate with other renovations requiring more immediate attention.

I have worked in my attic before...
Back in the days, when I brought the insulation from R-11 / R-19 up to R-50.

In that time I drew the following conclusions:
1. It's not somewhere I want to be for any length of time.
2. It's hot up there on a mild day.
3. I have no business being in an unfinished attic.

It pretty much rules out any uses such as for drying clothes, not to mention the humidity...

I picked up a second clothes dryer for free. I keep it out side in the shed, the shed has 220 volt power already for air compressor, plasma cutter and welding machines.
During the summer I use the clothes line and out side clothes dryer.
The boss says she wants her clothes ran through the dryer. She works in a hospital and we have a dog that never stops sheading. Other wise I would not own a clothes dryer, as I did for 6 years when I lived in virginia.

I didn't realize how much energy it was saving. The house stays a lot cooler during the summer not using a clothes dryer thats for sure.

Then during the winter we use the inside clothes dryer, vented inside the house. If it uses 2.2KwH per cycle thats over 12,000 BTUs of reused heat.

Dont worry about winter, clothes will still dry.
In maine we used the clothes line out side in the middle of winter.
Hang clothes up, they freeze solid but will still dry but will take a day or 2. We also had a lot of wind blowing.

It is hot because of lack of ventilation. Drying clothes in unventilated space and humidifying it up there on a regular basis might encourage pests, mold and odor.

Any expert here who can weigh in on this?

Not an expert in building science, but I can tell you this: if your attic becomes unbearably hot on a sunny afternoon year-round, it isn't ventilated properly and is costing you comfort and/or money. Likewise, if a damp load of laundry is enough to mold up the attic, something is awry. By design, attic spaces should be able to breathe.