Sunday, June 8, 2014

Cloth Diapers

Part of the reason for using cloth diapers with Elora was cost savings. Disposable diapers can cost less than a quarter each, but that can add up over three years.

.. but, as I watch the diapers go through a fifth wash cycle to be stripped (they periodically need a deep clean), I wonder, how much am I actually saving?

So I did the math. While the calculation will be subtly different for each user, I think this makes for a good real-world example.

The setup:
Our standard diaper wash uses three cycles on various settings. For purposes of analysis, I have to assume these are all 'Normal' cycles (which is what EnergyStar evaluates). Given the mix of cold, hot and sanitize cycles, this may be appropriate. We use two separate dryer cycles, but since performance is measured by weight, this should make minimal difference.

SnoPUD charges residential customers $0.09437/kWh during the winter (less during summer).
Alderwood Water has a tiered system, from a base level included, then from $2.40/CCF to $3.50/CCF. Taking the average of my last billing cycle, we will use $1.8625/CCF.

Our appliances are quite new and by most measures considered "Energy Efficient". The 3.9cuft washer has a Modified Energy Factor of 3.3 (cuft/kwh), and a Water Consumption Factor of 2.90. The dryer has a DOE rating of 3.01 (lb/kwh). The covers and liners weight 9lb.

Wash: ( (1/3.3MEF * 3.9cuft * $0.04237/kwh) + (3.9cuft * 2.9 WCF / 100CCF * $1.8625/CCF)) * 3 cycles / 30 diapers = ($0.05007 + $0.2106) * 3/30 = $0.026072
Dry: 1 / 3.01(lb/kWh) * 9lb *  $0.04237/kWh / 30 diapers = $0.004223
TOTAL = $0.03030 per cleaned diaper.

Of course, there's an up-front cost too. Assuming the Amazon price of $17.99, plus a $39.99 sprayer, you have an up-front cost of $579.69. There is a healthy resale market, but I'm assuming buying new and keeping forever.

Now, let's compare to disposables. Costco's cheapest diapers (averaging equally between sizes 1-2, 3 and 4) cost $0.1831 / diaper, offering a potential profit is $0.1528 per diaper.

BREAK EVEN POINT: 3794 diapers.

National Geographic estimated a child uses 3796 diapers in a lifetime. As a father, that doesn't seem even remotely possible. I would take a wild guess, and place that number closer to 5000, and estimate a modest profit of $180. The profit increases more if you can reuse the diapers with a second child, or resell them.