I was thinking about clothes dryers the other day

[EatenByLimestone]

It’s too bad that they don’t have outside air kits. Taking cold air from outside and heating it would really lower the relative humidity of that air. That could really increase the speed of the drying and lower fuel usage. It seems like it’d be an easy thing to incorporate into a design too!

 

[cygnus]

Yeah, good point.

I usually think about refrigerators this time of year. It bothers me that it runs to exchange heat indoors where it's 70 degrees when its 30 degrees outside.

 

[RockyMtnGriz]

I suppose I could open the window in the laundry room. Just so long as I don't freeze up the washer.

cygnus - If it helps you be less bothered consider that any energy your fridge wastes this time of year at least equates to resistance heating. I give the electric wasters less quarter in the summer when the heat isn't needed, or worse if it has to be heat-pumped to the outside.

 

[EbS-P]

I have considered what a complete thermal system for a house would look like. Tesla has the Octa valve the tech exists to have all thermal equipment running on a swingle compressor. It just doesn’t make sense for the complexity and the scale of savings.

You could always hang your laundry out.
If you think about it’s possible it is more costly to heat the air from outside temps with resistive heat than the air being able to hold more water.

 

[begreen]

It’s too bad that they don’t have outside air kits. Taking cold air from outside and heating it would really lower the relative humidity of that air. That could really increase the speed of the drying and lower fuel usage. It seems like it’d be an easy thing to incorporate into a design too!

It depends. Our outside air for the past few days has been 100% humidity vs 51% indoors. In parts of the country I'd guess that there are many times when the outside air humidity is higher in the summer than the air conditioned humidity indoors.

You could always hang your laundry out.

Often not an option for apartment dwellers.

 

[EbS-P]

It depends. Our outside air for the past few days has been 100% humidity vs 51% indoors. In parts of the country I'd guess that there are many times when the outside air humidity is higher in the summer than the air conditioned humidity indoors.


Often not an option for apartment dwellers.

Is running a dehumidifier inside and hanging laundry inside more cost effective than a dryer? I think it would e I’d you needed heat.

But at that point a heatpump dryer is probably what you want.

 

[gthomas785]

Often not an option for apartment dwellers.

All a matter of perspective. We have some friends in Romania who live in an apartment block. Washing machines are pretty common but no body has a dryer. It's perfectly normal to hang laundry either on the balcony or on racks in the bedroom.

 

[begreen]

Indeed, there are strong cultural differences.

 

[bogieb]

All a matter of perspective. We have some friends in Romania who live in an apartment block. Washing machines are pretty common but no body has a dryer. It's perfectly normal to hang laundry either on the balcony or on racks in the bedroom.

Had a landlord once that told us we couldn't hang laundry. We had been going to the laundry mat to wash the clothes, then hanging them on racks inside. They could see the racks thru the windows and told us not to do that any more.

During summer, the humidity inside and outside is pretty high. This past summer there were probably less than 10 days I could hang laundry outside and they would actually dry in 6-8 hours (nothing like bringing them in and having to run the drier anyway). Believe me, if I could hang clothes out more, I would as I like my basement to stay cool and there is no AC down there.

During winter the humidity on my main floor can get as low as 20% even with running humidifiers. And it is even lower in the basement since I don't run a humidifier down there . I do hang some stuff on drying racks, but there isn't much room (my basement is filled with pellets), so I do still run the drier.

So, in my situation, an OAK for the drier just would not help - outside air is too moist during summer, and why bring in cold air in the winter when I already have super dry air?

This fall I decided to recoup the heat and humidity from my drier by venting inside. I set that up 2 weeks ago once the humidity had fallen to 40%. My conditions are such that there is no risk of mold (low humidity, wide open basement for the air to circulate, heated with pellet stove so walls aren't cold, only a couple of loads per week and not on same day etc). I'll switch it back to outside venting probably in March or whenever the humidity starts rising naturally.

 

[gthomas785]

Yes it really comes down to regional weather conditions. For example where my friends live that I mentioned, it is typically pretty dry, not too hot, but they can hang their clothes up for maybe 1-2 hours and then it's done so it just doesn't occur to anyone why you would need a dryer. On the other hand here in New England, the thought of hanging damp wet cloths anywhere just doesn't make sense because it would get moldy.
Then there was the time I stayed a couple of months in a swanky apartment in Melbourne, the conditions were ideal for drying laundry on the balcony but we were told it was forbidden because the neighbors didn't like to look at it.

I also recently hooked up a "BetterVent" indoor dryer filter, I've tried it a few times and it seems to work ok. The only concerning thing was I got a little bit of condensation on the exterior walls near the dryer during the first part of the cycle, but it seemed to go away quickly so maybe it's fine??? Hooked it in with a diverter tee so I can switch it back to outdoor venting whenever I want.

 

[EbS-P]

Yes it really comes down to regional weather conditions. For example where my friends live that I mentioned, it is typically pretty dry, not too hot, but they can hang their clothes up for maybe 1-2 hours and then it's done so it just doesn't occur to anyone why you would need a dryer. On the other hand here in New England, the thought of hanging damp wet cloths anywhere just doesn't make sense because it would get moldy.
Then there was the time I stayed a couple of months in a swanky apartment in Melbourne, the conditions were ideal for drying laundry on the balcony but we were told it was forbidden because the neighbors didn't like to look at it.

I also recently hooked up a "BetterVent" indoor dryer filter, I've tried it a few times and it seems to work ok. The only concerning thing was I got a little bit of condensation on the exterior walls near the dryer during the first part of the cycle, but it seemed to go away quickly so maybe it's fine??? Hooked it in with a diverter tee so I can switch it back to outdoor venting whenever I want.

I did this too only with pantyhose. And then only on the coldest 5 days of the year. I would get condensation on all the wall of the laundry room with the door open. My conclusion was it’s not at all worth the condensation risk.

Now that I have a dehumidifier and am tracking indoor humidity I’m like WTF was I thinking. My dehumidifier is still cycling regularly and set at 58%. If one vents the dryer indoors you need a really open space or fan to distribute the moist air.

100+ years ago nobody had dryers. I would venture to say the didn’t wear moldy clothes but did go through life acustom to mildewy smells. Again a heatpump dryer fixes all these issues. Condensation is drained away and the air gears heated over the hot coil and back to the dryer. It needs no external vent therefore suck no cold dry or warm moist air back into the house.

 

[gthomas785]

Our indoor humidity is pretty low in the winter, and running the dryer with the indoor vent bumped the %RH in the next room by maybe a few percent. Nothing crazy.

My view is that a short duration blast of warm damp air like that is much different than a persistent high humidity problem in a house. I guess it's not too different than the bathroom when I take a shower, those walls get steamed up then too but it dissipates fast in the winter. My main concern would be if there was enough condensation briefly to potentially damage the paint but so far that hasn't happened.

 

[gthomas785]

And yes, whenever our dryer kicks it I plan to replace it with a heat pump one. But our budget line whirlpool electric dryer is only ~10 years old and seems to have plenty of life in it. We have a 1985 Maytag washer that is also going strong, just got new belts a year ago.

 

[bigealta]

If you are venting a dryer inside look into making a lint trap with a 5 gallon bucket. I made one for utah house and it works great. Those small ones you can buy don't work at all, they are Way to small.
something like this. And you don't need the quick connect, Just put the end of the hose in the cut hole.

 

[DonTee]

I’d love to rig up a big valve so I can duct my dryer inside during the winter. We struggle to keep the humidity in the high 30% range. Most of the time it’s lower than that.

My woodstove evaporates 2-3 gallons of water a day from the pot on top and it’s still that dry inside. Old school humidifier

 

[bigealta]

I’d love to rig up a big valve so I can duct my dryer inside during the winter. We struggle to keep the humidity in the high 30% range. Most of the time it’s lower than that.

My woodstove evaporates 2-3 gallons of water a day from the pot on top and it’s still that dry inside. Old school humidifier

You can easily buy a pvc T with a 1 way flap at depot / lowes. I have one. Fits right into the dryer exhaust vent. Just switch positions of dryer vent on the T when you want to redirect the exhaust.

It's originally designed to hook up 2 dryers to 1 vent.

 

[madeyeson]

I suppose I could open the window in the laundry room. Just so long as I don't freeze up the washer.

cygnus - If it helps you be less bothered consider that any energy your fridge wastes this time of year at least equates to resistance heating. I give the electric wasters less quarter in the summer when the heat isn't needed, or worse if it has to be heat-pumped to the outside.

The cold air will drop when it comes in the open window. It can freeze stuff below the window, like water lines, etc. even if the room temp is in the 70s and the window is open a just a little. (50 years drilling wells and thawing water lines.)
I live in a trailer house inside a steel building and our Northern Minnesota winter air is often quite dry, so I hang dry in the long trailer house hallway. In the summer I hang outside. Haven't had a dryer in over 30 years. I heat with a large Vogelzang parlor stove in the front room and do a lot of my winter cooking on top.
On another note: All chimney fires are caused by burning wet wood. A slow fire and/or a cold chimney makes it worse. The mass of a masonry chimney also makes it hard to adequately warm up the chimney. It usually takes hours or more. An insulated metal chimney can adequately warm up in minutes. The type of wood makes no difference. All people who are planning on heating with wood should be required to use a windowed parlor stove for 3 winters. It will train them. They'll be able to see the creosote buildup on the glass which also cuts down on the infra-red heat from the stove.
The creosote is caused by tars trapped in the moisture from the wet wood which condenses on the inside of the chimney and especially a cold chimney. When the moisture evaporates leaving the tars (creosote) behind you have coated the inside of your chimney with an accelerant. If you do it on purpose with a can of tar and a brush, it's called arson.