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Cleaning clothes in cold water
April 21, 2006 12:18 PM   Subscribe

Does cold water laundry detergent get everything properly clean? Really? Honest?

My Mum and Cheryl Mendelson agree: heat helps get out dirt and sanitize clothing. So I always use hot water on cotton underwear, sheets, personal towels and kitchen towels. Cold is fine for most other clothing, although white socks also go in hot water.

But my husband has started buying cold water detergent and thinks that should be fine to clean everything: jeans, socks, undewear, sheets, towels, etc., although he still sorts laundry by type, soil and weight.

Is he right? Should I feel free to wash everything in cold water?
posted by rosemere to Home & Garden (23 answers total)
 
Unless your hot water is boiling hot, it's not going to sanitize anything. Nor is it likely to clean any better than cold water detergent in cold water. Laundry detergents intended for use with cold water dissolve at a lower water temp and have different surfactants (that's what keeps the dirt from re-depositing). Detergents intended for use in warm water won't work as well in cold water.

Sorting by type and weight and level of dirt is good, because that way your jeans won't wreck your dress shirts. (and you won't wind up with a bra stuck inside the sleeve of your workshirt.)
posted by jlkr at 12:27 PM on April 21, 2006


If the clothes are getting as clean as he wants them to be, then he's right -- for his stuff. You won't know if the results will be good enough for you unless you try it. I find that whites are noticeably cleaner after being washed in hot water, and that pretreated spots of cooking oil, red wine, tomato, chocolate, and lipstick come out in warm/hot water but not in cold. (Pretreated! Hot water will set untreated tough stains.)

Here's something that sounds interesting to me: in an October, 2005 study of laundry detergent, Consumer reports found that Tide detergent for cold water (in a cold-water wash) cleaned as well as regular Tide did (hot water). Both were rated 'excellent.' But when they used Cold Water Tide in warm water, the results were rated 'very good.'
posted by wryly at 12:39 PM on April 21, 2006


I wash everything cold and I've got no complaints.
posted by knave at 12:41 PM on April 21, 2006


Warm/hot water more easily dissolves powder detergents. With liquid detergents, it doesn't really matter (and most detergents, especially ones labeled for cold, are [likely] optimized for cold temperatures).

This suggests to me that increased heat may accelerate chemical reactions to get stains out or to decrease the viscocity of oils (which are really good at trapping stains).

Ah, this article backs up my notion that heat = helps dissolve oils responsible for trapping stains (and contributing to stains).
posted by PurplePorpoise at 12:47 PM on April 21, 2006


agreed with jikr -- the only sanitizing heat does is if it is boiling-hot water. Your regular hotwater tank water is not boiling, and won't sanitize. It may help break up certain messes better in some cases, but doesn't do any sanitizing.

The only thing I don't wash in cold water is bedding, unders, and towels, but just because -- not for any particular "better" clean, I don't suppose. Traditionally, perhaps.
posted by vanoakenfold at 12:50 PM on April 21, 2006


In this AskMe response, MeetMegan reports that a P&G employee says that Cold Water Tide is the same thing, just with a different label, fragrance, and dye.
posted by zsazsa at 1:04 PM on April 21, 2006


There's no sterilization but hot water does have a higher saturation point so anything that can be dissolved will to better in warmer water. Additionally, a big part of what you're doing is removing oils and they flow better when warmer.

Which isn't to say that the cold water detergent isn't plenty good enough to accomplish the job, but there are some reasons why warmer water would clean better.
posted by phearlez at 1:09 PM on April 21, 2006


Oh yeah, well my husband is an elevator mechanic who gets dirtier than a coal miner on an average day, and we always wash in cold with the cheapest non-generic powdered detergent (I think Purex) and his clothes come out just fine. Mind you they're black to begin with. I think it just depends on how much you obsess about this kind of thing (Cheryl Mendelson, I'm looking your way).
posted by scratch at 1:17 PM on April 21, 2006


Thanks for raising that, zsazsa. Never pay more for "cold water" liquid detergent. It's the EXACT same thing as regular stuff but wtih different dye and fragrance (and sometimes a different - higher - price).
posted by MeetMegan at 2:17 PM on April 21, 2006


Hmm. I'm having allergy desensitization therapy and my doctor told me to always wash my sheets in hot water. However, according to him only front-loading washing machines can get hot enough to kill the dust mites. Since I have a top-loader, I have to get it started with three kettles of boiling water from the kitchen (which apparently raises the temperature enough to make a difference). Which is a long-winded way of saying that most normal machines don't get hot enough to sterilize, but if you've got a European-style front-loader, yours might.
posted by web-goddess at 2:26 PM on April 21, 2006


I always heard that it mostly didn't matter what temperature of water you washed your clothes in, because the dryer was the place where most of the germs were killed.
posted by viachicago at 2:56 PM on April 21, 2006


only front-loading washing machines can get hot enough to kill the dust mites

This is pretty bogus advice for a doctor to be giving you. Washing machines don't "get hot," i.e., they don't have heating coils. The temperature that the water is going into the washer is as hot as it's going to get.
posted by kindall at 3:01 PM on April 21, 2006


Besides which, if you really care about sterilization, you probably ought to be adding bleach to your wash, no?

That may not go over so well if your clothes have, you know, colors.
posted by Caviar at 3:20 PM on April 21, 2006


If washing in cold water is wrong, I don't want to be right have been living in filth my entire life. And I don't smell and people seem to like me okay, so there's that.

I also have dust-mite allergies, and my doctor is totally unconcerned with the water temperature for washing my sheets and stuff. There are much better steps you can take, like using mattress and pillow covers, and washing bedclothes (at normal temperature) with a special mite-killing solution.
posted by booksandlibretti at 3:44 PM on April 21, 2006


I wash all of my clothes in cold water, and always have. My girlfriend washes them in hot. I've never noticed any difference, except when the hot water causes something to shrink.

The hot water definitely isn't hot enough to sterilize anything, and the only argument I can see for using it would be that the soap dissolves more easily. If you're using any liquid soap, that won't be a problem. And it's never been a problem for me with powder, so I'm leaning toward it doesn't matter at all, ever. Considering the extra energy needed to heat up the water, I think it's better to go cold.

You may be interested in this straight dope article on laundry balls. While testing laundry balls vs. detergent, he found that detergent didn't really make much difference when compared to just using water. So just buy whatever smells best to you, and go with it.
posted by team lowkey at 3:54 PM on April 21, 2006


Well... re-reading that article, it looks like they pretreated the stains with a detergent first, so extra detergent didn't do any good. Here's something more useful about how detergent actually works, which may help you make a more informed decision about whether hot or cold water might effect the process.
posted by team lowkey at 4:05 PM on April 21, 2006


Can I derail this just a little to be more specific -- I have a bunch of white t-shirts whose collars have gone yellow after wearing them in sweaty conditions too many times.

The shirts are otherwise in good condition but I'm too embarrassed to wear them because of the discoloration.

Is there anything that will make their collars white again?

I've tried spraying them with a pre-wash stain removing solution and soaking them in nappy/diaper wash products. No joy. Might a hot wash make any difference?
posted by AmbroseChapel at 5:28 PM on April 21, 2006


Although both soaps and detergents are technically surfactants, there is a difference in the way soaps and detergents work, particularly in hard water. It's more important to use the proper amount and kinds of laundry products for the soils, stains and fabrics involved, than the temperature of the water. In the U.S. and the EU, and elsewhere in the world as trade customs dictate, most clothing articles now have standard care labels, and it pays to read and pay attention to them. Fabrics meant to be washed in cold water are so identified, and their dyes or materials will probably not standup to repeated hot water washing.

I live in an area where the municipal water supply is fairly "hard," meaning we have noticeable amounts of naturally dissolved calcium carbonate in our water. For cotton fabric whites (underwear, bed linens, towels, bath robes, etc.) I use hot water wash, detergent, and chlorine bleach, with cold water rinse. For most cotton and cotton/polyester blend casual shirts and pants, I use cold water wash and rinse, minimal detergent, and oxygen bleach as needed to maintain bright colors. Nylon and synthetic materials get cold water wash and rinse with detergent and borax additive. I rarely use fabric softener of any type, but I acknowledge I would have less fabric pilling and perhaps longer garment life if I did.

For AmbroseChapel: The standard reciepe for cleaning cotton or cotton/polyester men's Tshirts is hot water, detergent, sufficient chlorine bleach (1 & 1/2 cups in a top loading washer), and the maximum cycle time. Don't load the washer too heavily, as it is important that the shirts be well agitated for the entire cycle. Then, if possible, dry outdoors in sunshine. Works a treat, even for old shirts.
posted by paulsc at 5:42 PM on April 21, 2006


I was taught that hot water can cause some protein-based stains to "set", so cold water is better for protein stains (grass I think, blood).

I always wash in cold water unless the load is full of icky items (bathmats, rags).
posted by amtho at 6:57 AM on April 22, 2006


cold water is better for protein stains

Yup. Blood comes out right away with cold water and ammonia.
posted by nekton at 9:22 AM on April 22, 2006


Thanks paulsc. I hadn't even considered that the drying method would be part of the solution.
posted by AmbroseChapel at 11:53 PM on April 22, 2006


kindall: This is pretty bogus advice for a doctor to be giving you. Washing machines don't "get hot," i.e., they don't have heating coils.

Actually, most (if not all) front loading washers do have heating coils.
posted by jlkr at 8:55 PM on April 23, 2006


I *always* used to wash my clothes in cold water. They always come out clean. And it eliminated the need to separate whites and darks, since I've never had colours run in a cold wash. My girlfriend refuses to allow this practice since I moved in with her though, as it was the accepted wisdom that hot water washes better when she was growing up, and my 10th grade science experiment results weren't convincing to her.
posted by antifuse at 1:32 AM on April 24, 2006


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