Let’s talk dishwashing and dishwashers

Last week, I saw this tweet and it led me down a rabbit hole

While typing this, I found this article that says a dishwasher consumes about 1.2 kWh which is about 11 cents in WA state. I think you can get a 25 pack of detergent pods for about $5 so 20 cents. Then however much 3-4 gallons of water costs, so the tweet is fairly accurate.

It mostly resonated with me because my wife usually waits until we have a “full load” and she runs it about 2-3 times a week. This sucks because we both hate unloading the dishwasher and just seeing a fully loaded dishwasher sucks. Not to mention the fact it doesn’t clean as well when it’s fully loaded.

Then I stumbled onto this Youtube video. I watched most of it, but I’ll TLDR it for you. First off, dishwashers have 2 spots for us to add detergent – the main compartment and a ‘pre-wash’ compartment. I’m sure 95% of people just throw a pack into the main compartment and call it a day. Well it turns out your dishwasher runs a 15 minute cycle to get the gunk out of your dishes first. Because we aren’t filling in the ‘pre-wash’ compartment, then it’s only using water for this cycle versus using detergent+water. You can already see this isn’t very efficient. After that 15 minute cycle, the dishwasher then runs the main cycle, which is when it uses your detergent pod.

The second thing I learned is that it’s not necessary to pre-wash your dishes. Right now, my wife sort of washes the dishes first before putting it into the dishwasher, so it’s double washing. Once you factor in the time wasted AND THE AMOUNT OF WATER SHE USES, it’s all totally unnecessary. So after watching the video, I told her to load all the dishes that night w/o pre-washing it. She had LOTS of doubt that it’d work, and you know, it washed it just fine. The only thing it didn’t fully wash was a small dish that had caked eggs on it (but the dish was probably partially blocked too. Not having to pre-wash the dishes now will save us a lot of time and wasted water.

Lessons learned today – 1. you do NOT need to pre-wash your dishes, 2. add some detergent to the pre-wash and 3. run your dishwasher more often. Now go tell your Asian parents all this.

10 comments on “Let’s talk dishwashing and dishwashers

  1. If you don’t pre wash at least the big pieces of food, the drain from the dishwasher to the garbage disposal can get blocked. Had that happen multiple times

    Also, with a full load, I think you would be using the water more efficiently

    1. I mean I’m not going to put a chicken bone in there, but I’m sure bits of rice left over would be fine.

      A dishwasher uses 3 gallons of water per load; Seattle rates look lik it’s 2.5c per gallon, so 7.5c. If you run it 2-3 times more per week, then you’re out an additional quarter per week. I’d rather do low to mid-sized loads just because it’s easier to manage. Plus you won’t need as many dishes/silverware if you run it more often too.

  2. For some odd reason, I found that youtube video several months ago and found it fascinating as well. While the pods may seem cheap at 20 cents per pod, he said it’s even cheaper (and just as efficient) to buy the old fashioned box of dishwasher detergent and sprinkle some into the soap bin (only 1/3 of the way up) and sprinkle a little on the outside to use as a pre-rinse. Infinitely cheaper and really not that much work. I’ve been using the box detergent, generic Great Value brand, and it works find. I also have a battery operated fan by geek aire that I bought for other uses and after the cycle is done, I open the dishwasher, put the fan on the door, and dry the dishes with the fan. I think the drying cycle is what uses the most electricity. Maybe a bit extreme, but I feel happy with the results.

    1. I thought about your fan idea for a second but then I realized the dishwasher only uses 1 kW of power for the whole process, so why go through all that to save less than a quarter of electricity… plus I’d think the hot air it uses to dry would be more efficient(?) than a fan blowing cold air (kinda like a hair dryer blowing hot air vs cold air.)

  3. Regarding double washing, I prefer post-washing. I’d rather have the dishwasher do the heavy lifting. 95% of the time dishes are clean. If that doesn’t work you can give the machine a second chance too.

    1. Ah I never thought about it that way, but yeah you’re right, post-washing is the way to go. Or like you said, just run it again.

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