Dishwasher Cycle Length

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eurekastar

eurekastar

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Amarillo, Texas
Can someone please explain why modern dishwashers take so long to complete a cycle?

I currently have a Kenmore Elite that was installed last November. It does a fantastic job cleaning the dishes. However, with the heated wash and sani-rinse options selected, it takes almost five hours to complete a cycle. In my last house, I had a Bosch dishwasher that took well over three hours. It also did an outstanding job but took forever.

I wish I still had my old Kitchenaid dishwasher that was made by Hobart. That thing was a tank and it was loud and used lots of water...but the results were always outstanding and a normal wash cycle took about an hour!

eurekastar-2018091209565503824_1.jpg
 
This has been discussed ad-nauseum over the years here.

Modern dishwashers, to save water and electricity, and to meet the sound quietness demands of the market, run longer for the following reasons:

Much less water use. Old dishwashers filled with up to 2gal. of water per charge. New ones fill with 1gal or less. This small pool of water requires smaller passages and water jets. As well as much smaller pumps.

The smaller pumps use much less power.
Many folks think their dw running for 3 hours uses more power, but it's not true when you're running only a 40watt motor. Over, say a 150-200watt motor for 45min - 1hr.

Much smaller water pools are faster and easier to heat, than 2gal on a 120v line.

Because of the lower water use, the volume of water spraying through the smaller jets needs much more time to spray and soak the load.

Newer dishwasher detergents with enzymes have either helped push this cycle time creep, or have worked with it. Such as, enzyme detergents need more time and cooler water to properly work and break down protein/starch stains.

A large marketing advantage to these smaller pumps and lower water volume, is much quieter running machines.
In the marketplace, it's been a "race to the bottom" to make the quietest machine. And with the advent of more open floorplans in homes over the decades, consumers want those quieter machines.
The caveat to that is larger volume pumps with food grinders, have had to be replaced with water saving filter systems.

Now don't let the filters scare you though.
Many filters in modern dishwashers don't need cleaning except for every couple months. And if you're an avid pre-rinser like most of America, you could get away with cleaning the filter only 1-2 times a year.
 
So if today's enzyme detergents work best at lower temperatures, does that mean I really don't need to add the heated wash option? The temp out of the tap is about 130 degrees.
 
John Summed it Up

Regarding the water heating, I think the heated wash option does make for cleaner silverware on my 2011 Whirlpool.

 

But I don't know if it's because of the hotter water or the added wash time that's needed to heat the water.  Probably both, but there's no way to know how much of the effect is from each.
 
Added Heat

Added heat is likely still fine because there will be a slow ramp-up of the water heating.
Since the main wash portions of new machines are often around 40-50min, that gives the enzymes a good 15-20min to soak before the machine ramps up the heat to 130F or 140F in the main wash with heat boost.
Therefore, the enzymes will still have time to work in the beginning.

I usually use heat boost for really greasy loads, or with cookware on the crusty side.
If i've done lots of work with raw meat, I'll use a Sani-rinse.
 
The Pro Wash setting on our KA takes about 2.5 hours without sani or heated dry.. I've never tried those two extras so don't know how long it would add.

We always use the one hour was (without heated dry) and it cleans just as well, in an hour..

I cannot for the life of me figure out how running it for 2.5 to 3 hours is going to save money over it running for 1 hour ..The motor is running continuously pretty much in either setting..
 
Dishwasher Cycle Length!

The cycle times are absolutely Ridiculous! I have a GE tall tub that is 17 years old and get done on 80 mins and that is more than enough time. It never cost much to run a dishwasher anyway - if this machine goes out to pasture - I would try to get a vintage machine or just do them by hand and use paper plates if necessary! It is unbelievable what things have come to!
 
paper plates

Wow, so in order to avoid a modern machine that factually uses little energy and water, yet some extra time, you're going to blow your money on paper plates and create extra trash?

That's special.

1 HOUR WASH

The 1hr Wash cycles on WP machines speeds up the process by using 6 gallons of water and running the heater in almost all segments.
That's opposed to the machine using as little as 2.5gal of water on the Normal cycle.

ENERGY

Now, it may not matter to some, but empirically, as stated above, the small, magnet motors on modern machines DO use less electricity than machines of previous designs with larger induction motors.

I'll break the power numbers down, again.

My modern KA has a 35watt "pond pump" motor.
The Normal cycle will often run for, let's say 2.5hrs.
35w x 2.5hrs = 87.5watthours

Older machines had 1.8-1.2 amp induction motors.
For sake of argument, let's take the 1.2 amp motor.
We need to find out its watts.
Using a generic power factor of .8 for AC power.
.8PF × 1.2amps × 120volts = 115.2 watts.

Older dishwashers ran for about 70 minutes.
That's 1.16 hours.
115.2w x 1.16hrs = 133.6watthours

Let's say you run your dishwasher a conservative amount of 3x a week.

87.5 x 3 = 262.5wh

133.6 x 3 = 400.9wh

As you can see there, the savings really start to compound over time, in just a a theoretical week.

So yes, running cycle to cycle, the modern machine vs. the older machine doesn't save THAT much.
But over time, it's a huge savings in water and power.

Now I know that doesn't matter to many here, but in the grand scheme of things, it matters a lot.
To communities, power/water utilities, especially if it's a generally dry area.

I'll give you more anecdotal evidence.
My 1400 sq/ft house today, has 30% lower electric bills, compared to all the past apartments I've lived in, in past years.
Because of all the energy saving appliances and lights and HVAC I have.

Even as recent as 3 years ago, in my old apartment, with old appliances, lights and HVAC, my electric bills were about $60 a month.

THIS past August, in a larger dwelling, still using all my stuff, and with slightly higher electric rates than 3 years ago, my electric bill was $45.

That's serious savings.
 
In my line of thinking the newer dishwashers are "overnight" machines.  Kind of like that combo washer/dryer in another thread that takes 4+ hours for a load.

 

Not so great for those in the routine of putting the dishes away before bed or who don't like to run appliances unattended. 

 

 

 
 
I have a low-end Whirlpool dishwasher (mine's portable) purchased in the summer of 2017 and it cleans very well using the 1-hr. cycle. That's one hour before it hits the 20-minute dry portion of the cycle, which I don't use anyway. I've used the Normal and Heavy Duty cycles once each just to see how they operate, but didn't think the results were any better than the short cycle. Good thing, too; this beast is LOUD out in the open.

Caveat: Eddie (ea56) has the built-in version and had problems with it in month 10 of ownership. Mine flooded once (also during month ten) but has worked flawlessly ever since.
 
Bill, I have an Elite that was brand new model  introduced August 2015 that was discontinued last winter/early spring.  It was the TOL Elite when announced.  I have the same wash arm as your machine. Mine has the MicroClean (self-cleaning filter). 

 

I have only maxed outwith all the options once and the initial time on the display was just under 5 hours--Pots & Pans, Sani Rinse, TurboZone, and SmartDry Plus.  My loads are usually heavy soiled and sit for severaql days sometimes--I don't pre-rinse.  Without heated dry Pots & Pans is 2:16.  Normal is 1:41 and Smart Wash is 1:57.  Smart Dry adds 56 minutes and Smart Dry Plus is a total of 1:32 added on.  My water temperature is 120.  I have learned that when using Smart Wash or Normal without water heating or dry, my soiled loads end up adding 48 to 57 minutes.  I have found just using Pots & Pans yields the same results with less time.  In fact, Pots & Pans ends up 5-10 minutes less than initial start time when it's finished.  For heaviest soil, I'll use Pots & Pans and high-temp wash.  That will result in a main wash of 87 to 89 minutes.  Depending upon soil, the main wash ranges from 66 to 78 minutes on both Smart Wash and Normal.  If I do opt for Sani Rinse, I don't use heated dry at all because the heating element is rarely on, even with max dry option.  And things dry just as well.  BTW, my model # has 14833 and a 221 precedes those numbers I think. 
 
The model number on this unit is 14759. I ran a load last night on Speed Wash was very surprised and pleased with the results. Everything came out sparkling clean with one exception. That exception was a dish with baked on cheese. The Smart Wash Cycle would have tackled that with no problem.

Most of the dishes had been in the dishwasher for several days, including a few knives with peanut butter. There also was a bowl with dried on egg and an aluminum griddle with a bacon fat. They all came clean!
 
Your DWs manual indicates that 5h with sanitize are in the realm of possible.

So your inlet water might just be particulary cold increasing the cycle time by a lot.

Most soils are relatively easy to clean. Even a lot of dried on stuff is washed away pretty decently.
Just baked on soils need verry long soaking times.
Thus, Pots and Pans should default to 4 1/2h on your model.

Only thing to keep in mind is that Express always uses about 6gal of water, no matter which loading or soil conditions.
 

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