While we tested the products in normal use, we found that using the pails one at a time did not provide us adequate information to give side-by-side ratings and comparison on the key metric of odor control. So we developed a torture test that sought to stress test all the products in an identical manner, at the same time, and allowed us to really compared performance side-by-side.
The Nasty Business of Sniff Tests
In order to test diaper disposal pails on the critical metric of "odor control" we developed our own sniff test procedure (well someone had to do it). To do so, we dressed up in a style reminiscent of a Hazmat suit (see photo above) to limit exposure to the noxious fumes. Here's the basic outline of our process:
- Collect a large amount of fresh stinky poop
- Mix it up to assure that each pail is tested with a similar mix of "test material"
- Divide the test material into equal weight portions
- Place each pail's test material on the center of a small paper plate
- Put the plate with test material inside the manufacturer's recommended bags
- Allow the pails to sit undisturbed at room temperature (we tried different time periods, 1 hour, 4 hours, 8 hours, and 24 hours, and found 4 hours allowed us the best opportunity to measure differences)
- Perform sniff tests with the pail closed
- Perform a diaper drop sniff test (opening the pail to insert a new dirty diaper inside)
We performed this sniff test three times, each time using a different source of "test material."
Scoring was based on averaging assessment of odor control from each judge comparing each pail against the others. Each product was given a rating on odor control relative to the competition on a scale of 0-10, where 10 is best.
Although these tests were admittedly subjective in nature, in that they were based on the sniff test opinions of human judges rather than readings from a scientific measuring device, we feel they were fairly conducted across pails and provided a reasonable way to test and compare each product's performance.
In the end, we felt this testing process was successful as it allowed us to detect significant differences in each pail's ability to control odors. However, we also included tester input from parents who used the pails in their homes during testing. Ordinary day-to-day use that is identical to the actual intended use of the products was also considered in the final odor scoring. How the products performed in the nursery played a minor but key role in how products were ranked.
The One Hand Rule and Diaper Disposal
To test each pail on the metric of "Ease of Diaper Disposal" we used only one hand to insert a dirty diaper into the pail. One hand operation is key as there are many times where a parent needs to have baby in one arm to dispose of the dirty diaper with the other.
Each product was given a rating from 0-10 when compared to the other products, with 10 being the easiest to use.
While we found that those pails that include a foot pedal are moderately easier to use than those without, all of the products we reviewed could be operated with one hand without much difficulty. However, depending on the design of the open and close mechanism some might require a "shoving" of the diaper if the inner bag is on the full side, or parents might still have to struggle to open a pail while holding a diaper in the same hand. Those that required extra shoving or potential "hang ups" of full diapers scored lower than those that didn't.
Ease of Changing the Bags
We tested the difficulty in changing the bags on each pail and rated them compared to one another on a scale 0-10 with 10 being the easiest to change. Part of the scoring on the bag changing included whether you were subjected to a nasty stink as part of the bag change. Other considerations included bag snagging, tipping of the pails, shin bumps, and wall damage as a result of full bag struggles and top heavy designs.
Estimation of Total Cost of Ownership
We estimated the total cost of ownership for each pails by calculating the approximate number of bag refills used assuming that 5,000 diapers are disposed of (our estimate of a single child's output over four years). The calculation factored in the variance in size of diapers from newborn to later stage diapers (the diaper bags can hold more than 2x the number of newborn diapers as compared to the larger later stages), and the approximate number of diapers in various sizes that will typically be used over four years.
We used approximate street prices for diaper bag refill cost calculations, and also assumed "economy-minded" shopping habits such as buying the less expensive per refill multi-packs (such as the 3-refill pack available for the Diaper Genie) to arrive at our total lifetime costs.
While we don't claim to be able to exactly predict your total cost of ownership (your mileage will vary), but we do believe our estimates provide a reasonable basis for comparison.