I know that my Miele W4840 heats the water for all temperatures, not just than Sanitize, and not just on the Sanitize cycle. My hot water supply takes a long time to flush out the cold water, so the machine often fills with tepid water. I can tell when the heater is on, since the machine is plugged in through a Kill-A-Watt monitor. It sometimes has to heat the water a little even for a Warm wash. It always has to heat for a Very Warm or Hot or Sanitize wash. The actual temperatures are listed in the manual. Can't say that I've verified them exhaustively. I have checked Warm and Very Warm a couple of times; the door won't unlock when it gets hotter than that.

Also, I've observed that the cycle timer will pause if necessary, to allow the water to finish heating. The heater is only 1050W. My heating times do suffer from the fact that my incoming water is so tepid. With a better hot water supply, it would be a lot faster e.g. raising 120degF domestic hot water to Hot (140degF) wouldn't take all that long.

Caveat: Most of my observations are on the Custom cycle. I've seen the heater operate on Handwash and Comforters, never seen it pause the timer on those cycles (probably because they can't be set above Warm). I have little or no experience with other cycles. The heater doesn't operate on the Normal cycle, which is therefore useless IMO. But Custom is pretty much the same thing.

We're satisfied with the rinsing. We hardly ever use the Sensitive option (extra rinse), and I haven't enabled the extra-rinse or extra-water configuration settings that some W4840 owners here have used.

My Bosch Nexxt 500plus does use the water heater in all cycles. It uses ATC to get as close to the desired temperature as possible and then it will use the heater to keep the temperature steady throughout the wash cycle.A cold wash will not be below 60F, which is about the minimum temperature for detergents to be effective.
The sanitary cycle reaches 170 degrees for at least 3 minutes and then cools down to 150 degrees. This should be very effective in killing most bacteria, fungi and dust mites.
I have had the washer for almost 18 months now and I am very pleased with it. It does a great job cleaning and rinsing clothes and it saves lots of water and energy compared to a TL. I didn't have any problems with it so far. Let me know if you have additional questions.

Let me add, the Electrolux uses the heating element in all cycles to maintain a set temp.

Sanitize cycle goes up to 152 degrees Fahrenheit.

Selecting COLD water: heater will kick in if temp. falls below 65 degreen Fahrenheit.

Selecting WARM water: heater will kick in if temp. falls below 78 degrees Fahrenheit.

Selectiing HOT water: heater will kick in if temp. falls below 120 degrees Fahrenheit.

This info. was e-mailed to me from Electrolux.

I know your original post says FL, but in case your interested and as far as I know, the Maytag Bravos 800 series HE TL also uses the heater in every cycle if you select the "clean boost with heater" option.

I do know the water reaches 153 degrees on it's sanitary cycle but not sure about the temps on the other cycles when you select hot, warm, cool and cold (I'd imagine cold is just tap cold).

And FYI, I keep seeing pretty consistent rave reviews of this washer!

My grandmother has the old series 6600 Bravos and loves it! It holds a MASSIVE amount of clothes, gets them really clean and also rinses them very thoroughly. The spray-rinse feature (which is still available on the 800 series) I find very effective not to mention water-saving. Hope this info helps!! :o)

Here is a link that might be useful: Maytag Bravos with heater at Lowe's

I have the Bosch Nexxt 800.

I strongly recommend AGAINST it.

That said, it heats the water on ALL cycles, including the cold and delicate cycles. This is not mentioned in any of Bosch's sales literature or the user manual; I was told by customer service after I called to complain that my washer was using warm water in a cold setting. I wish I had realized that before I purchased because I would not have purchased it and would not have the lemon I am now stuck with.

Bottom line, my washer has two, randomly occurring chronic problems.

1. The drum will not turn at all during the entire cycle and then it beeps as if it is finished over an hour later.

You know that this happened, bc when to go to take the laundry from the washer and put it in the dryer, you realize part of the load is completely dry, while the area where the water spilled the detergent and other laundry additives, is sopping wet. Lucky for me that I don't use bleach!

2. The washer will not spin at a high speed.

I'm not talking super high, it decides to flop the clothing around very slowly and just never bothers to get up to any speed at all. Thus, you are left with a sopping wet load that has not been rinsed properly! I assume the machine is attempting to "balance" the load prior to high speed spinning, and never manages to become content. This problem occurs at least one day a week and on that day will occur for several load-attempts in a row. It has happened on Cold and Hot washes and on my follow-up attempts to do a "Refresh" cycle, which is a rinse and spin. It has happened on both full and small loads, even loads of towels-only, which should be the easiest to balance.

This machine has no option for "Spin" only. The only way to get it to spin is to learn the special button combo from a repairman.

I've had my machines since July 21, 2008, and have yet to have the problem corrected by Bosch. I have reported this problem on GW before and other owners of this machine have emailed me asking if I had the problem corrected bc they were having the same trouble.

Buyer beware!

One more tip for the OP -

My son used to have terrible eczema from his buttocks to the back of his knees. The ped. thought it was due to detergent or softeners, since it seemed to be a contact issue from sitting.

We now don't use any softener and use only Charlies Soap, powdered, and use white vinegar in the softener dispenser. His skin has completely healed over the past 7 months! He hasn't had an outbreak in at least 3 months and we are so happy!

We also have a whole-house water filter that removes all the chlorine from our household water, as well as a water softener.

It may be the combo of all the above, but I do recommend Charlies Soap bc it rinses completely and does a decent job of getting the clothes clean.