Monday, September 30, 2024

Why sustainability cannot be reduced to monetary savings - Case of Drying clothes

The point of this post is that making the most sustainable choice requires an ethic or mentality that goes beyond evaluating the returns to being sustainable in purely monetary terms such cost savings. Here I illustrate this in the context of drying clothes











* - Includes amortized cost of dryer per load (see #1 below)
** - Includes energy for driving to a laundromat

1. Machine Drying at Home

A clothes dryer let us say uses 2kW of power and runs for an hour and so consumer 2 kWhr which @ an electricity price of $0.3 per kWh is $0.6 per load. Lets say a good dryer costs $700 and when used twice a week lasts about 7 years, which implies a cost of $700/(2*52*7) which is ~ $1 per load. Therefore, the total cost of machine drying = $1.6 per load

Lets assume the electricity carbon intensity is 350 gCO2/kWh. The carbon emission per load is 700 gCO2/load or 0.7 kgCO2/load. At a carbon cost of $100 per ton of CO2 ($0.1 per kg CO2), the carbon cost is  = 0.7 kgCO2/load  * $0.1 per kgCO2 = $0.07 per load, which is a mere 5% of out of pocket costs

2. Machine Drying at a Laundromat

Laundromat's charge $2.25 per load and lets say it takes about 20 extra minutes to make the trip. Let's say the value of leisure time for people without a machine inside their own home or apartment building is $30 per hour, which means an extra $10 per load. The total cost of using a laundromat is $12.25 per load which is 7X cost of machine drying at home

Energy for driving to laundromat:


3. Sun drying on a clothesline  - own time

Lets say it takes one about 20 minutes to hang a typical load of clothes from the washer to dry in the sun and take it off once dried.  Since when it comes out of a dryer hot and hence easy to fold without crease, it takes 10 extra minutes to fold for a total of 30 minutes. If the average person values leisure time at $50 per hour (i.e., they need to be paid or be saving the equivalent of $50 before tax), then the cost of drying the clothes in the sun using one's own time is $25 per load, which is about 15X cost of using machine. I use a higher opportunity cost for a person having a own home with space to dry clothes (apartments dont allow people to hang clothes as I found out as a grad student trying to save on dryer costs)

4. Sun drying on a clothesline - hired househelp

Alternatively, if one employed hired services for household cleaning etc. one is looking at a cost of $30 per hour, then you could say it is $15 per load which is about 10X cost of using machine

Bottomline, being drying clothes sustainably cannot be justified by cost savings. Of course, if you have your home powered by clean electricity the case for not using dryer is weaker and one has to motivations such as not wanting to rely on machines etc. So you need to simply enjoy the activity of hanging clothes to dry or try to do derive more utility from taking the time to hang clothes to dry. One could be do something in parallel like spending time doing it with a family member or listening to a good podcast while doing it.  Another is to treat it akin to nicotine patch helping overcoming self-control issues if the saved time is going to be spent on staring at a screen. 

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