CLothes Dryer Science

OK here’s the situation. I take a load of laundry out of the washer and open the door to the dryer only to find some towels in there that I dried yesterday. So now I have to put the clothes back in the washer, take out the towels, and take them to the bedroom for folding before I can then take the clothes out of the washer again. Frankly, I don’t have the time. I’m a busy guy. So I tell myself that it is actually more efficient to mix wet clothes with dry on the theory that some of the moisture will transfer to the dry clothes and therefore increase the surface to be dried and decrease the time required. Am I full of hooey or what?

Yes, you’re ful lof hooey. The total mass which needs to be heated has been increased, and nothing’s going to be dry until those towels get nice and hot. What you should do is keep a laundry basket in the laundry room, to dump your clean, dry laundry into.

When you take a load to the washer and start it up.


G E T O R G A N I Z E D !

I disagree. I don’t think it would be much of a problem, assuming the OP doesn’t overfill the dryer and prevent the clothes from being able to move around.

In either situation, you have a fixed amount of liquid water to be vaporized. Yes, you have to now heat up a larger mass of clothes, but the extra energy required is simply that required to heat up the initial mass of dry clothes. It takes far more energy to heat up water (with its high heat capacity) and to vaporize it than it does to heat up a relatively small mass of clothing. (Note that by comparing the mass of wet and dry clothing, it is evident that most of the mass of wet laundry is water.)

Oh, and just to clarify: I don’t believe adding wet laundry to dry laundry will reduce the time required to dry the clothes. I think that doing so will increase the time, but not significantly. (That is, assuming the clothes can still move around.)

Why do you have to fold the towels before you can use the dryer again??? Just pull the towels out, put them somewhere and then get the dryer started. Then you can deal with folding the towels when you have the time.

Experiments, anyone?

Geez, just throw the towels on the floor. If they get dirty, you can wash 'em again.

(Of course, I live in an area with cheap electricity and no water bills).

If the towels have been sitting in the dryer all day, they will be all wrinkly. If you leave them in the dryer when you add the wet stuff, the wrinkles will be fluffed out again.

Your towels get wrinkly just sitting the dryer (not on the floor with you stepping on them)?

You worry about wrinkly towels?

My dryer has a nice built in area for the purpose of storing recently dried clothes whilst filling the dryer with newly washed and wet clothes.

I like to call this area “the top of the dryer.”

I’d say the answer depends on the relative humidity in your dryer. If the dryer keeps the air fairly dry, then more surface area means shorter dry time. If the dryer has crappy airflow and the air stays just about saturdated with water, then more surface area isn’t going to help (and the added bulk will just make the airflow problem worse.)

If I had an appropriate scale to weigh the wet/dry/etc. items, I’d definitely give this an experimental test. (It’s tricky, though, because to get a lot of moisture transfer, you may need a lot of wet stuff, in which case the additional surface area from the towel(s) may be too little to notice.)

Ok I have to confess that part of what I was doing with my question was looking for a justification for my laziness/absentmindedness. And by the way, in my cramped quarters the washer and dryer are in the kitchen and have to function as countertops. The OP was serious, however. Let me ask it another way. Is there any point at which a combination of wet/dry clothing is more efficient? Lets say I have a dryer full of dry towels and I need to dry just one article of clothing, my favorite Hawaiian shirt. Should I empty the dryer or just sling it (the shirt) in with the towels?

This problem is obviously so complex as to be completely unsolvable. You must therefore throw all the towels and clothes away and go out and buy new ones.

Next time don’t be so insanely foolish. Put a mirror on a stick and carefully search every corner of your dryer (and washer) for recalcitrant towels and clothing.

Do you conduct the rest of your life with such monstrous carelessness? It is to shudder!

In questions where it is difficult to easily conclude the merits of one case vs the other, I generally go to contemplation of the extremes.

Think about how long it would take to dry one soaking wet tea towel. Fifteen minutes maybe?

Now think about stuffing that wet tea towel in a dryer jammed full of cold dry bath towels. Do you think this could possibly be quicker?

What would happen if you stuffed one more dry bath towel in the dryer? Do you think that would be even quicker? Yes? Then jam a few more in there !

How about the other extreme? One dry towel and one wet towel?

Actually I conduct most of my life peering hopelessly into the void, navigating the random chaotic gravitational pull of two Jack Russells and a hound dog mutt, and cruising for beer and skittles.

I do believe you’re getting my point. But I think you could get a little more extreme than that.

I presume you mean one wet towel only? But that wouldn’t really answer my question, would it? I was hoping for some definitive scientific answer but I guess I’ll do an experiment with your extreme and my extreme and that should tell me something.

Well, if you have a dryer full of dry towels and toss in one small wet article, I think that article is going to dry pretty quick because it’s moisture will be distributed amongst the dry stuff. There is also going to be a significant amount of physical rubbing to help pull the moisture from the wet article. Everything in the dryer will fairly rapidly wind up a little bit wet, which could be good enough for government work. In order to get “fully” dry, however, you still need to heat and vaporize all that water, which will take time.

One other thing to consider is the “action” the items get. Sticking one small towel in might not give you enough agitation to get it dried efficiently, then it would be worth it to throw in a couple more dry towels to get the stuff mixing well.