Half of a year-old pillow's weight is dust mites?

I keep hearing (on Oprah once even) that if your pillow is older than a year, that half its weight is made up of dust mites. Here's some figures I've come up with, so if anyone can confirm or debunk this please do.

According to the Wikipedia, most folks lose .3 to .45 kg of skin per year.

Assuming that we only spend ~1/3 of our time in bed, there's ~2/3 of the time to lose this skin elsewhere. It can only be assumed the amount we lose in the shower is significant, but if we consider that we are rolling around with sheets on top and beneath us that could cause a significant portion to slough off also. Lets assume that 50% comes off as we sleep.

.3 to .45kg * .5 = .15 to .225kg

It would also be prudent to assume that since we don't wrap ourselves in the pillow that only a portion of that amount will make its way into the pillow. So assuming that you sleep on your pillow with 25% of your surface, which is a bit on the high side probably...

.15 to .225kg*.25=.0375 to .05625kg

Hmm. That number is getting kind of low. OK, so lets make an assumption about our little buggers. We know that they are not just made of our cast off skin, and they require humidity, so it would be safe to assume that they are also composed of water. Since we have no information on their composition, let's assume they are 90% H20, 10% solids from eating the dead.

.0375 to .05625kg/.1 =
.375 to .5625kg

500 grams is about $21.50 in Quarters, and I've gone high on my estimates.
Does your pillow increase its weight that much per year? I think not. Sounds conceivable, but working it out, uh... doesn't.

[snapdragonfly]

Okay, I'm not good at math, also kg's mean nothing to me. But if we are looking at half a pillow's weight being dust mites - or anything for that matter - it can only be as much as half the pillow's weight.

My pillow is pretty dang light. I don't know, maybe a few ounces at most? How many quarters is that? Much less than 21.50 in quarters - that would weigh a LOT more than my pillow.

So help me with the math - if my pillow only weighs 6 oz, then how many kg's would half of that be?

[stalker]

Originally Posted by snapdragonfly

So help me with the math - if my pillow only weighs 6 oz, then how many kg's would half of that be?

6 ounces = 0.170097139 kilograms