Tuesday, April 15, 2008

#207 - Powder to the People

Switching from liquid dishwashing detergent to a powder

Yes, we're talking about my dishwasher. Again. Seems I just can't stop messing with that nightly routine. It irks me that I don't have the mental will to skip the pre-rinse and so I am trying to compensate by over analyzing all the other aspects involved in making my Corelleware shine.

You may recall that way back in November, I gave up my Cascade in favor of a gentler liquid detergent - Seventh Generation. Great product. Worked like a freakin' charm and without all the phosphates and fragrances. So why change again then?

Well the Liquid 7G comes in a plastic bottle, whereas the Powder 7G comes in a cardboard box. We all know that plastic is a petroleum-based product made from a non-renewable resource and that it cannot be recycled, rather, it can only be down-cycled into fleece, park benches, sleeping bags and whatnot. Cardboard, on the other hand, comes from a renewable resource and, in fact, this particular box is made from recycled fibers. Cardboard can also be recycled many times before the fibers break down too much to be useful.

So really, it's all about the packaging. Not the product.

But as long as we're on the subject of dishwashers, I thought you might like to know that I've worked very hard to minimize the amount of water I use when pre-rinsing. I've got it down to a trickle that I shut on and off while rinsing and I keep the plug in the drain so that I can just swish the silverware around at the end. Anyhow, all this obsessing has dropped my pre-rinse water usage down to a paltry 2 gallons per night. Armed with these reduced numbers, I have since developed a little formula here that proves that, for me at least, pre-rinsing my dishes actually saves energy. I know. I know. I need to let this go, but I CAN'T! Anyhow, here goes:

Pre-rinsing my dishes utilizes two gallons of cold water (I don't use the hot water for pre-rinsing) This allows me to use the short cycle on my dishwasher, which gives me a total of:

  • 2 gallons cold water
  • 6.1 gallons hot water
  • 36 minutes of electricity

This means I've used 8.1 total gallons of water. And at 440 BTU's to heat one gallon of water, we've used 2,684 BTU's of energy (.786 kWh). I've also used .84 kWh for the motor. That totals 1.626 kWh.

If I don't pre-rinse, I skip the 2 gallons of cold rinsing water, however, I'm now forced to use the Heavy Wash setting on the dishwasher to get all the crud off the dishes. This means I'll be using:

  • 0 gallons of cold water
  • 8.5 gallons of hot water
  • 89 minutes of electricity

Broken down, this equates to 8.5 gallons of water, 3740 BTU's (1.095 kWh) and 2.08 kWh for the motor, for a total of 3.175kWh.

So, here's the comparison:

PRE-RINSE: 8.1 gallons and 1.626 kWh vs. HEAVY CYCLE: 8.5 gallons and 3.175 kWh

Hands down winner is the pre-rinsing, saving me over 146 gallons of water and 565 kWh per year! Whew! Now FINALLY I can rinse in peace!

19 comments:

organicneedle said...

I was totally going to talk about my dishwasher this week too. (I swear we were separated at birth...our very nerdy birth.)I switched to the scrape method awhile back after reading a Consumer Reports article about how not only did it save a ton of water, but also the scrapping itself put cracks in the crust allowing the dishwasher to do its thing better. Let go of the rinse, Erin. It's okay...you can do it.

The CFO Now said...

Wow! I'm totally impressed with your math numbers! I would never have been able to figure that out! I have a hard time letting go of rinsing too. So I'm glad your numbers worked out the way they did! :)

Brian said...

Hmm...we scrape/rinse right off the table to make washing easier, and then use two sinks of water (rinsing into the washing water)...so, 20-30 minutes or elbow grease, 4-5 gallons of water...but, that's only because our water is so hard that a dishwasher leaves horrible spots. Otherwise, we'd wash everything in the dishwasher...including the kids...

BTW, don't you have a dog that could handle all that pre-rinsing??

PlanningQueen said...

I am so impressed with the vigour that you have analysed the dishwashing process!

organicneedle said...

Oh...you were so right about the hanger thing. The details are in todays post.

e4 said...

Lies, damn lies, and statistics. ;)

I was thinking about trying this. In fact, you've motivated me to try to mix up a batch today...

equa yona(Big Bear) said...

I have read that there are studies PROVING that using the dishwasher is more ecologically sound than washing by hand. Now, youhave to decide what you're going to do based on time etc. But let me say here and now, those studies are bull shit. I wash dishes by hand. Amount of electricity used-0. I start with an inch or so of soapy water, rinse over my wash basin, save the water I use in a bucket and use it to flush the toilet. Water wasted-maybe a pint or two.
Time we spend doing dishes as a team, half hour a day.
Just an observation.

Green Bean said...

I'm with Orgie. Let go of the rinse, let go, let go.

As to the powder, nice choice, We use a powder too from Ecover that comes in cardboard. I felt so stupid last year when I realized that the individually wrapped plastic Ecover tablets weren't the bees knees. I might have been using an environmentally friendly detergent but it was soaked in plastic.

eco 'burban mom said...

I recently let go of my cascade tablet thingys... I loved the convienience of the little tabs so my boys could acutally load thie thing without too much mess. I was giddy to recently find Ecover dishwashing tabs! www.ecover.com They have all sorts of dishwashing and laundy detergents, but hooray -They have the tabs that are still plant based and completely biodegradable!!

homeschoolmom said...

Here's a tip for your powdered dishwasher detergent -- don't dump it from the box to the dishwasher cup. Instead, pour powder into a storage container and use a spoon to measure the powder into the dw cup. I swear to you it takes longer to type than to do. I had to replace my Kitchenaid dw last year and got an uber-expensive Bosch, mainly hoping it'll last, but also because the wash cycle I use most only takes 3.5 gallons of water. Read the manual and found that it recommended 1 tbsp of powder. Checked myself and found that I was routinely dumping 2 tbsp into the cup. It just happened that I had a plastic measuring spoon I never use which was 1/2 tbsp. Just by using a spoon I'm saving 1 1/2 tbsp of powder every single day. (Of course, I was a dw powder glutton...) The dishes are perfectly clean as well.

I try not to prerinse, but it's a hard habit to break. Maybe try putting one plate in unrinsed and seeing if your dw really does get it clean. Then if it doesn't work, you only have that one plate to scrub and re-wash...and you can let go of the idea that you're being bad for prerinsing. Of course, if it works fine...well, you just got permission to drop the prerinsing chore. Whoo-hoo!

Heather said...

Dude, you're going to smolder in compost hell if you don't stop rinsing. Let the dog lick them off, fer pete's sake.

All the cool people are doing it.

arduous said...

Is your powdered 7G working? I got to tell you, I switched to the powder for the reasons you state, but ... it's not really getting the job done. I'm not using 7G though so if that's working for you I'll try it out.

MamaBird said...

You are my SuperDork twin (check out my recycling meeting minutes ;) -- I am so glad you *did* this! I have a similar dilemma and I'm glad you crunched the #s no pun intended. Now I just need to use up my 17000 bottles of 7th generation liquid (case discount) in order to go back to powder. Do you have hard water in VA too? Do you use a rinse agent? I have been using vinegar... anyhoo, general question, how do you do all this estimating of water usage? Do you measure water out in gallon jugs or what?!

Leslie said...

I wanna see you calculate how much you sweat the details. Would that be measured in sweat "beads" or "bullets"?
You are amazin' Burbanmom.
I'm a rinser.

Jenna said...

The liquid is much more in agreement with septic tanks, though... so even though the packaging is more eco-friendly, I'll just have to keep recycling my plastic liquid bottles.

Jessica said...

It seems like you could save the packaging and money by using baking soda (or washing soda) and borax for detergent. It lasts forever, and I know you can buy the baking soda in bulk. I posted a recipe on my blog at www.practicalnourishment.com

(go to http://tinyurl.com/53qac8 for the specific detergent recipe).

rubiemcqutie said...

As another commenter stated we do the two sink washup system. One sink is filled and used to wash dirty dishes. The other half of the sink is also filled and used to rinse. Cleanest dishes get washed first all the way down to the dirtiest. I then use the dishwasher for it's true purpose, to steralize. No detergent. It's not needed. My dishes come out squeaky clean.

I will say this before I worked out this system. I did a series of trial and errors and this is what worked for me. I could never get 7Gen dishwasher granuals to fully breakdown and wash away in the dishwasher.

CindyW said...

Me too, switched from 7th Gen liquid to 7th Gen powder. Works about the same without creating unnecessary plastic waste. Even at the end of life cardboard can be composted.

I actually don't pre-rinse and just use the wash cycle. Seems to work fine. Maybe I need glasses...

Chile said...

Hm, I'm a lot more efficient by hand. I partially fill a bowl on one side of the sink with cool water while letting it heat up. This is used for rinsing detergent off clean dishes. I use about 4" of hot water on the other side, in a tub, to wash the dirty dishes.

Before washing, all crumbs and leftover veg debris are scraped into compost. After washing, all water is dumped in the tree wells. Because I am vegan and cook without added fat, I don't worry about pathogens or oils on the ground.

Total water use? Less than 2 gallons.

I also occasionally reduce the gas used to heat the water by heating up a pot of cold water in my solar oven...