Well, that's got some merit, if the only reason you use hot water is for killing dust mites. But there's many more reasons for using hot water for washing and use lower dryer temps as many newer dryers do. Actually many new dryers don't give the temp to do this. If you have a very old or very cheap dryer, the high temp can still be there.

And given the "return" to clotheslines that's becoming more common today, There's a decrease (albeit not massive and complete conversion) in dryer use.

There's a lot of threads on performance in the laundry, appliance and cleaning forums so I won't go into great detail here, but here's a few other reasons:

-Powdered detergents and additives dissolve much better in hot water
-Enzymes, many detergents and additives work better in hot water
-Using a profile wash will remove many stains better
-Using cold wash and a hot dryer can set stains in clothes so that they're difficult or nearly impossible to remove (if not impossible!)

No sense rehashing what's far better explained elsewhere, but just some more info to consider.

For years allergists told us to wash bedding in hot water to sanitize against dust mites, etc. Now they've realized that most people no longer hang their laundry out to dry and that dryer heat is plenty hot enough to do the job.

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Who are they "they" you refer to?
The doctors we know still recommend hot water.... for a variety of reasons (as cynic mentions).

I read this in the Home section of the Chicago Tribune a couple weeks ago. It was a round-up on "living green". It didn't sound quite right to me, and several posts on GardenWeb also think it's faulty.

I'm calling for Consumer Report to set up an old boiler washer and pit it against some ladies pounding sheets on rocks in a stream!

LOL, yeah, they might, but from what I've seen of Consumer Reports in the last 20 years or so, they'd probably substitute charcoal briquettes and then find it unsatisfactory because the "rocks" left a few dark marks on the white sheets! And not realize that you have to apply heat to get something to boil. :D

Yeah, OK, I have lost respect for CR..

Enzymes are temperature dependant, they're not so good when it's too cool, but they don't like it too hot either. Around 30-40 degrees is normally ideal, go too far above this and they denature. If you want to wash hot, it's best to use a non-biological powder because it's designed to work better without any enzymes.

Biological powders are however better for the environment and save me money I find, they provide good washing results at lower temperatures, and they contain less phosphates and other similar compounds which are bad for the environment. The lower temperatures should also be better for clothing, and reduce scale deposits in your washing machine too (if you have hard water).

I wash everything at 30 degrees with biological powder and almost every item comes out clean, while washing at 50 degrees with non-biological wasn't so good. I also find you can use less powder when its biological.