I've been washing sheets in hot water for a while now and so far, none appear to have shrunk noticeably and the elastic seems to be holding up OK. Some of the really dark cartoon-like designs for the kids may have faded a bit but at the rate that is happening I'd expect the sheets to wear out before the design fades too much.

I would think that the higher temperatures in the dryer vs. the washer (at least for non-boosted hot washes) would be more damaging on the elastic anyway, since they run hotter than the wash water. Perhaps a hot water wash and a delicate dry cycle if you are concerned?

I've been washing sheets in 160 degree water for 5 years and haven't lost a sheet yet. I always dry on delicate and maybe that's the solution. Shrinkage comes from the dryer, not the water temperature in the wash. Hope that helps.

I have washed sheets in hot water without damaging them. Cotton sheets should definitely withstand the heat.

Also -- bleach (if the sheets are white) or vinegar (if they're not) will kill bacteria and/or mites.

If your washer has an agitator, I'd recommend 1 cup for a full load. If it's an HE washer, I'd recommend 1/2 cup.

peabody -- a few more recommendations: Encase your mattress and pillows in soft plastic or vinyl covers made especially for the purpose of killing (by suffocation) dust mites that live in all mattresses and pillows.

Wash ALL your bedcovers (blankets and all) in the hottest water which is safe for the fabric, once a week. If they must be washed in cold water, I'd recommend Lysol concentrate (not the household cleaner) in the wash, and vinegar in the final rinse.

Ditto for curtains/drapes, stuffed animals -- anything in your bedroom which is made of cloth.

When you vacuum, be sure your vacuum has a very good HEPA filter -- the best on the market.

If you have a ceiling fan, clean it weekly. Vacuum it well, then wash the blades with Lysol water.

If you have carpet on your floors, you might want to consider taking them up and laying hardwood. That was my son's allergist's recommendation, as it is very difficult to kill dust mites which live in carpet. We already had hardwood floors and no carpet, so that was not an issue for us.

We replaced our upholstered living room and family room furniture with leather furniture to prevent dust mite inhabitation.

Also -- eating raw honey from a local source can help 'immunize' you to local pollens. Two tablespoons each day -- preferably one in the morning and one in the evening -- is a good 'dose'. My son ate it on toast, on oatmeal, in biscuits, etc.

ALL of these things made a HUGE difference in his life.

I realize this information is OT for this thread (and for this board!). Just thought it might be of help to you.

Here is a link that might be useful: Lysol concentrate

I don't understand why hot water would be superior to warm water washing of sheets for someone with allergies and asthma.

FREQUENT washing would help, and maybe a double rinse, but what's to gain with a few degrees higher wash water temperature?

graywings, my son's allergist said the hot water would kill mold spores and dust mites that warm water wouldn't.

I have learned since then that white vinegar is a great anti-bacterial agent, that it can kill mold (and mildew) if it is used in a hot wash. Don't know if it kills dust mites.

Again we're seeing ambiguous terms. "Hot" and "warm" are undefined terms. What may be hot for one is warm for another. Better to talk temperatures. Also, tap hot will vary since the water from your water heater may be 120° or 140° or whatever, but by the time it takes the cooled water from the lines, then is cooled by the water lines and further cooled in the machine itself, you could lose a lot of heat so actual temperatures will drop. The only way to know for sure is to put a thermometer in the washer.

So the actual temperature will have more to do with how it will affect killing of germs, bacteria, etc and how it will affect the materials. Some machines will heat to over 200° and that's not good for elastic. However, another "hot" temperature might be only 110° or less. That's quite a difference.

This comment is off-topic for the laundry forum but is in reference to the OP's concerns about bedding and allergies. My mother's nightly sneezing fits led her to buy a latex mattress and put dust mite impervious covers on her pillows. She found the mattress to be quite comfortable and has a pad on it that she washes weekly, but she did not like the feel of the impervious covers under the pillow case. As an alternative, she puts her pillows in the freezer every morning and takes them out a few hours before bedtime. She has not had a night-time sneezing fit in the 2 years she has been following this procedure.

Wouldn't the heat from a dryer be higher than a washer even on hot? If so, wouldn't that kill germs?

I would think that drying sheets on a high temperature would damage them more than washing them in hot water. (By hot water, I mean water which is at least 140 degrees.) JMHO

Does anyone know how hot a typical dryer gets? My guess is that on a normal setting dryers get to over 140 degrees.

High temp is typically ~155°F, with each successive lower setting usually being about 10°F less. Some units back in the 1950s could get up to 185°F.

My F&P SmartLoad is 149°F for high (Regular & Denim cycles), 140° medium (Perm Press), 127°F low (Delicate).

My Calypso dryer has five temps -
High (Heavy Duty & Towels/Cotton) = 155°F
Medium High (Normal) = 150°F
Medium (Bulky Items) = 140°F
Low (Casuals) = 125°F
Extra Low (Delicate) = 115°F

Presence of moisture in the clothes keeps the temp lower due to evaporation. I've checked a Regular load of towels in the SmartLoad after 15 mins or so and the items felt quite cool to the touch.

On other brands, specifically ASKO, the water temp can go as high as 205*. Now that is hot! I dare a dust mite to live through that.

www.protechallergies.com has some detergent you can use if you want wash in cold water and kille dust mites preventing deterioration in your sheets set

A washer with an onboard heater helps get those temps up. The asthma and allergy foundation has a certification program to test which washers run hot enough and well enough to kill dust mites and molds. Check them out. (I am allergic to every tree, shrub, mite, and mold that an allergist can test for save two. I feel your pain.)