From the Consumer Reports article cited below:

> When a family member is sick, use hot water mixed with chlorine bleach to reduce bacteria in the bed linens and towels. The same goes for cleaning dirty cloth diapers, or other messes.

But also,

> Heating water accounts for about 90 percent of the energy needed to run a washer

So I only use heat for special occasions.

Article: https://www.consumerreports.org/washing-machines/dont-bother...

The washing machine isn't a heat sterilizer, the point of using hot water was just to activate the detergents.

So when different clothes prescribe washing at different temperatures, it's because the ‘activation’ temperature of detergent changes depending on whether you use it with jeans or underwear?

As far as I know the clothes don’t prescribe a temperature to be washed at, but rather a maximum temperature threshold upto which the material can withstand without risking damage to itself.

So a 40°C cloth can be washed at any lower temp but might deform or loose color or even breakdown if washed warmer than that.

Instructions haven't kept up w/ washing machines and detergents.

> "Front-loaders and high-efficiency top-loaders run normal cycles 10 percent cooler than agitator washers, and the 'warm' wash temperature in the U.S. has declined by 15 degrees over the past 15 years," says Tracey Long, communications manager for P&G's fabric care products in North America. “Traditional detergent enzymes can be sluggish in cold water so we worked to create a mix of surfactants and enzymes that deliver cleaning performance in cold water across all product lines," says Long.

> Consumer Reports’ past tests found detergents have gotten much better at putting enzymes to work in removing dirt and stains at lower water temperatures, and are less effective at higher temperatures.

Source: Consumer Reports, "Don't Bother Using Hot Water to Wash Your Laundry: Consumer Reports' experts say cold water can get the job done", https://www.consumerreports.org/washing-machines/dont-bother...

If you want to sanitize anything, just use some bleach. It's harsh on fabric, but so is hot water, and the bleach will do a much better job. (FYI, I don't have any whites at all.)

My understanding that was for the special fabrics and/or the dyes used. For example raw indigo bleeds a whole lot more with higher heat. I know there are some fabrics and blends that are fragile compared to something like a cotton tshirt and recommend colder water.

I was recommended by a friend to put anti bacterial and wash with cold water so clothes won’t smell and won’t loose shape or color. Changed my life.

A tip we rediscovered a few years ago(it's well over a century old) is that adding a bit of borax to the washer not only helps get your laundry cleaner, but it will make all your laundry smell better, too, since borax/boron is an extremely powerful agent for killing bacteria, molds, and fungus. My wife is sold, and almost refuses to do the wash w/o borax anymore!

(This might even help deal with the continually scummy front-loader problem, but I can't speak to that as we prefer our 33-year-old Kenmore top loaders that can still actually be repaired rather than replaced with expensive new Chinese/Korean crap every few years. Mechanical timer controls and durable design and mfg FTW! For what it's worth, our total cost of purchase and repairs over 33 years is maybe $1200.00 for the washer/dryer set.)

Re: “we prefer our 33-year-old Kenmore top loaders that can still actually be repaired rather than replaced” http://recraigslist.com/2015/10/they-used-to-last-50-years/