Welcome back Readers!
This week we’re going to take a look back at the very first
Ops@Home topic. Laundry Day.
To recap, we had looked at ways to eliminate muda, or waste,
from the laundry process. Specifically,
we looked at reducing the number of times each article was handled. Less sorting, less effort, less time. We also tried to minimize waiting for the
washer and dryer by prioritizing the order loads get washed.
The experiments have been conducted, the results collected. Data has been graphed and scrutinized and analyzed. And here it is.
Let's start off with some assumptions:
- I didn't count and inventory each article of clothing. I'm assuming a week's worth of cloths is about the same from week to week.
- I didn't include the baby's laundry which gets done multiple times a week or sheets and towels. This was strictly done using the clothing of two adults.
- Time required to hang dry clothes was not included. This varies depending on the temperature and humidity of my house or if the clothes are hung outside.
The initial process split the clothes into three loads, Cold Wash (Blue), Warm Wash (Red) and Delicate Wash. In my case, I had too much clothing in the delicate pile for one load so it was split into two (Green and Purple).
This is what the time study for laundry day looked like:
From start to finish it took 5 hours and 42 minutes. Now, a lot of this was hands off time as the washer and dryer runs automatically, the beauty of modern conveniences. However, there was still intervention required during the sort, hang and fold operations.
One of the proposed changes was to eliminate the initial sort step by having a divided hamper and separating the clothes when they are placed in the hamper. This seemed like a great idea, but from the time study you can see that this step really only took 5 minutes.
The cost of a new divided hamper would range from $40 - $100, which is a significant investment for little time savings. The advantage to the sorting would be in the ability to easily delegate laundry to another member of my household. The instructions for how things needed to be washed could be put on the bags and when a bag is full, anyone could toss it in the laundry. Still not really worth the money for a new hamper.
So what did the revised process look like?
Looks better, doesn't it! The process improvements brought the total time down to 3 hours and 50 minutes.
To prioritize the loads, I used Johnson's Rule for n jobs on two machines. This meant that the hang to dry load is done last, as it doesn't require the use of the second machine (the dryer)
During the summer, I hang the clothes outside to dry on the line and try to get them out as early as possible to try to maximize their time in the sun. In that case, I wouldn't use the Johnson's Rule to prioritize the loads and would do the Hang to Dry load first. Changing only the order of the loads in the Revised Process, we can see Johnson's Rule at work.
When the Hang to Dry load is done first, the dryer is idle until after the second load goes through the wash. This extends the process time to 4 hours and 26 minutes.
Here is what the three versions of the process look like in comparison. As you can see, even the ordering of the loads can have an impact on the process time.
One of the proposed changes was to eliminate the initial sort step by having a divided hamper and separating the clothes when they are placed in the hamper. This seemed like a great idea, but from the time study you can see that this step really only took 5 minutes.
The cost of a new divided hamper would range from $40 - $100, which is a significant investment for little time savings. The advantage to the sorting would be in the ability to easily delegate laundry to another member of my household. The instructions for how things needed to be washed could be put on the bags and when a bag is full, anyone could toss it in the laundry. Still not really worth the money for a new hamper.
So what did the revised process look like?
Looks better, doesn't it! The process improvements brought the total time down to 3 hours and 50 minutes.
That's a savings of almost 2 hours!
A big time savings came from splitting the delicate load into two; one that went in the dryer and one that was hung to dry. This eliminated one full dryer cycle, which doesn't eliminate much labour, does save on energy. The revised process also removed the bulk of the user intervention between wash and dry cycles. Much less effort and labour.
To prioritize the loads, I used Johnson's Rule for n jobs on two machines. This meant that the hang to dry load is done last, as it doesn't require the use of the second machine (the dryer)
During the summer, I hang the clothes outside to dry on the line and try to get them out as early as possible to try to maximize their time in the sun. In that case, I wouldn't use the Johnson's Rule to prioritize the loads and would do the Hang to Dry load first. Changing only the order of the loads in the Revised Process, we can see Johnson's Rule at work.
When the Hang to Dry load is done first, the dryer is idle until after the second load goes through the wash. This extends the process time to 4 hours and 26 minutes.
Here is what the three versions of the process look like in comparison. As you can see, even the ordering of the loads can have an impact on the process time.
So going forward, I'll skip the divided hamper and keep sorting and washing the loads as follows:
- Delicate Wash, Perma Press Dry
- Cold Wash, Normal Dry
- Warm Wash, Normal Dry
- Delicate Wash, Hang to Dry
At least until it's warm enough to hang the clothes outside.
Happy Wash Day!
Alta, I'm very inspired by this post - have been mulling this over myself for several months. Just did a couple of loads of laundry at your mother's house last night and got talking about it. I do not have my own washing machine for part of the year when I live away from my home base in NS. So on Monday evenings I generally go to a friends house which is equipped with excellent laundry machines. I make dinner and we watch and discuss a couple of PBS shows. So figuring out which loads to do first has been important because it's a drag to hang around late at night waiting for the dryer when we are all talked out.
ReplyDeleteBut I have one comment to make about some basic assumptions you have made in this model. Your focus has been on optimizing the machine use, and I understand that this is where your effort and attention is needed for the job. But I wonder how this optimization would be different if your goal were to deliver the clothes ready for wearing in the most efficient way. Dirty to wearable in the shortest amount of time - would their necessarily be an increase in your own effort. I suppose you could stand and wave the hand drying around in the air for a couple of hours and that would speed it up but greatly increase your effort.
My point is that by doing the delicates that need to be air dried first then they have more time to get started on their drying before the final load comes out of the dryer. On the other hand in the dead of winter it will take at least overnight to dry some sweaters etc. so there is not much reduction in the time for readiness if you get it started a couple of hours earlier.
Hi Annie,
DeleteThanks so much for reading and commenting.
In process improvement, the goal is to eliminate waste and this is not just time. The easiest way to reduce the laundry time to zero is to buy new clothes every week. New clothes every week, no dirty clothes to wash, no time spent on laundry. And while I did resort to this once, in a pinch between back-to-back business trips, it is more wasteful from a cost and environmental perspective.
I agree completely with your comments on the order of the hang-to-dry load.
Anecdotally (I haven't actually measured this), I've found that it takes about 6 - 8 hours to hang dry clothes inside my house in the winter. They actually dry faster inside during the winter than the summer as the humidity is far less. During the summer when it is really humid, it can take up to 2 days to hang dry a load inside. In the sun, it will only take a couple hours.
As such, during the summer months it is worth having the cycle time extend by 40 minutes to get the clothes on the line in the sun. By the time the last load comes out of the dryer, the clothes on the line are dry.
During a home renovation that took much longer than it should, I relied on the laundry mat for three months. When I was doing laundry away from home I would leave the delicate load to last so that I could be out of the laundry mat sooner and get the wet hang-to-dry load up at home.
Good luck with the laundry!