I just used one in a rental house that was hooked to cold water. Dish washing was very poor, and we had to use the sani-rinse cycle to get the water heated adequately.

what does a cycle use? 10 gallons of water or something? Your hot water bill is driven by showers, baths, laundry, and other big uses, not the dishwasher.

And, remember that the DW is going to heat cold water itself, so you're probably going to see a rise in the electric bill instead.

heimert, you don't say what kind of dishwasher it was. If it was indeed a Miele and the washing results were as poor as you say, then something is wrong with the machine. If it wasn't a Miele (or other brand/model with assured water heating), then yours was an entirely different situation.

It's true that cold water connection isn't likely to result in significant energy savings due to the small amounts of water involved. However, one of the primary reasons for connecting a Euro-style dishwasher to cold water is so that the machine itself can control the target temperature per the selected cycle. Some cycles, such as china/crystal or delicate, are intended to operate at lower temperatures to protect the dishware. If the household water heater is set at 140ðF for example, that may be higher than the temperature-point of the cycle.

As for significantly raising the electric bill, that's unlikely to happen, either. As an example ... My DishDrawer only takes 0.8 gals per fill, so a normal cycle is 4 gals. The maximum Heavy cycle (seven water changes) is 5.6 gals. True that's only one drawer, but I rarely use both drawers. It takes me 3 to 5 days to get up a load in one drawer. I have the machine essentially connected to cold water. I have a tankless water heater which I keep set at 100ðF to 102ðF for showering, raising it with the temporary override function as needed (I don't raise it for the dishwasher). It takes several fills to purge the supply line due to the small water volume per fill and distance from water heater to kitchen, so at least half the cycle is cold water by default. I did some checking recently with a Kill-a-Watt meter. Dropping the tankless to 70ðF to insure cold water for the entire cycle, a Normal cycle used slightly less than 0.6 KWH of power, heating the main wash to 140ðF and the final rinse to 150ðF. That's the equivalent of six 100-watt light bulbs turned on for an hour. A Heavy cycle with the tankless left on 100ðF used exactly 0.68 KWH, which is 150ðF main wash and 163ðF final rinse. Six light bulbs turned on for an hour is not a lot of power in comparison to water heating, air conditioning, clothes dryer, etc. My ice tea maker pulls 625 watts, although it doesn't run for an hour. My crock pot is rated 200 watts (which I assume is the high setting), and a typical meat loaf recipe may take 3 to 4 hours at high, or 5 to 6 hours at low.

Why not install a "mixer" upstream from the DW hookup? This way, you can make a choice and simply adjust it later on if you don't like the results your getting. I am in the same situation since I am soon to start plumbing for a dishwasher and am considering this. It seems it would be a good idea to have a handy shutoff valve anyway, so couldn't this be put in so as to be able to mix hot or cold or use one or the other exclusively?

It was a Miele. Certainly possible that either something else was wrong or we operated it wrong. But on the "normal" cycle, there was a lot of dirt still on the dishes. On sani-wash, they were as clean as I would expect.

We have the Optima with the C&C cycle option. We opted to do a hot water hook-up. With a cold water hook-up, you have some energy savings along with the ability to use the C&C cycle for fine china and crystal, but longer cycle times overall. With a hot water hook-up your cycle times are shorter (not short, just shorter!), but you lose the ability to use C&C as intended.

All of our dishes, including the "good dishes" are DW, micro, freezer, and oven safe. The few fine crystal wine glasses we have (Baccarat champagne flute set), will never see the inside of a DW if I can help it--too delicate to even be inside a DW around other things! Our everyday wine glasses do fine in the DW with Normal cycle. So, I'd rather save the time. The water is going to need heating whether it's done by the DW or the hot water heater anyway, so I don't know how much energy savings we'd get with a cold water hook-up.....

CatMom is correct: if you want to use the China & Crystal cycle, then you must hook up to cold water.

We have 2 Excella units, so we decided to hook one up to cold water & the other to hot. The hot DW is used for heavy duty cleanup of food prep utensils & dish overflow, so we don't need C&C on that one, & it is faster. We have used C&C & Plastic on the cold water DW a lot. My favorite cycle is the Sensor Wash.

I think many cycles on my DW use about 4.2 gallons of water or less depending on soil and load size but the DW can use more if the soil level is high but no more than 6 gallons.

I connect mine to hot water, however my DW is not close to the water heater so the actual water is not all that hot, but better than the 38F degree water that comes out of the cold water line in the winter.

I don't wash fine china in the DW so don't really care about dish damage, but even if I did because of my situation I can still get a cooler fill for that cycle.

So it depends on your situation. If I cared about the china crystal thing ALOT then I would go with the cold water supply. Since I don't I opt for the hot water supply which helps speed up the cycle a little.

I have seen times where there is a temp delay using a hot fill (you can tell if the time remaining count down stops and holds the same time) The delay has never been more than 3 minutes and then the time countdown will resume, however this will only happen if there is some different unexpected condition because each time you run a cycle the DW will take the time it took to heat the water into consideration so that the next time you run that cycle the initial cycle time will already include the time it took to heat the water the last few times you ran that cycle.

Anyway it depends on your situation. For me no worries about china/crystal = hot water fill.

Here's what I was told by a Miele tech:

If you have a model that has the condensation drying (I forget the term they use); i.e. does NOT have a vent on the front, then you must use cold water for the drying to work effectively.

If you DO have a vent in front, then the choice is yours, with hot being preferred due to shorter cycles (not waiting as long for water to come to temp) and potentially better cleaning because all parts of the cycle will be with hot water as opposed to just two. Unless you're concerned about the china cycle, in which case you must do cold.

I use a cold water hookup on my La Perla -- I assumed it was the most flexible option, and my kitchen hot water is fed by my whole house softener so that was a no-no for the dishwasher. Feeding your DW house softened water will cause you no end of trouble with etching, etc., so I opted to feed unsoftened cold water and let the electronics in the DW decide what's best and how to adjust everything.

If I want a hot pre-wash, I select the "Heavy Soil" option which heats the pre-wash water. The only cycle I don't have access to is the Energy saving cycle which relies on hot water from the tap.

Just wanted to provide a quick follow-up. DW was installed today. (I can't wait to go home and play with it!) I finally decided to stick with the hot water hookup, and asked DH to run that decision by the installation guy one last time as well. Oddly enough, the installation guy said hot water was the "norm" so I guess most people in the Bay Area have been opting for the hot water fill!

Thanks again for all your advice.

Let us know how eveything works out with your play.

Post-install note: Installing on the hot water line should reduce energy usage a little.

You said you have a gas water heater. Gas water heaters use 1/4 to 1/3 less energy to heat water than electric (heating water is electric's most inefficient usage) so there will be a savings in total energy usage.

Mine is installed to hot and cold. I asked the Miele tech who installed my replacement dishwasher. His recommendation was to do hot/cold, since I don't own any china or crystal. My hot water comes from my boiler (indirect hot water heater) so it's much more efficient to use that than to heat the water in the dishwasher.

My 2 cents.