Real nappies or disposables?

The BBC are reporting a study done by the UK Environment Agency comparing the use of real nappies and disposables. Remarkably, the life-cycle analysis of environmental costs has come to the conclusion that there is little or no difference between them. At least, that is the headline. If you look deeper, there are several severe problems with both the study and the reporting.

The study is based on 2000 interviews, but only 32 of these were the “real nappy” sample. This means that the study is statistically flawed by the use of such a small sample.
The study assumes pretty much the worst-case use of real nappies – soaking dirty nappies in chemicals, washing small batches at high temperatures, tumble drying, and working out life-cycle costs over a single child’s time in nappies. However, many people don’t soak nappies (it doesn’t achieve much in our experience), wash fairly large batches (so fewer washes are needed, which means less energy) and hang their nappies on the line to dry (tumble driers are about the most energy-wasteful appliances there are). Even more than this, though, is the assumption that the production and disposal costs of the nappies apply only to a single child. If nappies are used on subsequent children (as they often are) and are passed on to other parents afterwards (which is common) or simply used as household cloths (which is also common), their costs must be spread out over these other uses, drastically reducing their environmental impact.
The study is being reported as saying “they’re no different, so I bet you feel stupid for advocating real nappies?” However, even if the report was correct in that most people are no better off environmentally using real nappies, surely the correct approach is instead to say “don’t soak nappies in bleach, wash at 60°C, don’t tumble dry and reuse them after your child’s potty trained”?
A more practical aspect is lost, however, in this study, which is simply that it costs much less money to use real nappies than disposables! The initial outlay is higher (perhaps £200 for a full set of nappies and wraps over the child’s time in nappies) but ongoing costs are far lower (just detergent and electricity for washing). By contrast, a child in disposables will easily cost £10 per week; over 2 years (generously), that’s £1000, and I’ve heard even higher estimates for the costs. That’s a significant saving, even if the environmental impacts were the same.

The take-home message, it seems to me, is never to take such things at face value. Indeed, this study seems so out of step with reality that I have to wonder whether it really was as “independent” as it’s meant to be. Or it could just be incompetent – I doubt that it would pass peer review for publication in a reputable journal, especially in view of the small sample size.

Update
OK, I’ve had a chance for a brief glance through the report, and some of my original criticisms above were off base – I blame the BBC for poor reporting :-) However, there are some even more extraordinary claims in the report than I’d thought.

The study doesn’t assume that all real nappies will be tumble dried, but does make the strange assumption that half of real nappy users will dispose of poo in the household waste, rather than flushing it down the toilet! They make this assumption based on the finding that half of real nappy users use non-flushable liners – but given the liner will have to be separated from the nappy anyway, do many people really throw it in the bin? But, then, I was amazed to find that most people using disposable nappies happily throw the entire contents of the nappy in the nappy bin – even though it’s illegal to dispose of human faecal matter in household rubbish!

Even stranger, apparently a tenth of real-nappy users iron their nappies, which (apart from its environmental impact) is surely just masochism :-.

But reading the report just confirms the tiny sample they’ve used – one crucial conclusion is based on just 2 respondents. In any case, the take-home message is still to use real nappies and to do so in a manner that keeps their impact as low as possible – not tumble drying, reusing nappies for several children, keeping detergent use and electricity costs down.

pax et bonum

Article posted at 10:56am on 19 May 2005
Category: Life, Politics, Science, Struggling, General

Maybe it was one of those independent surveys sponsored by Cosyfit …?
We used and reused real nappies for our first 3 (the same set – they were never out of use for about 6 years); by then they were so thin and worn out, and the wife ditto, that she insisted on us buying disposables for No. 4. I’m pretty sure it’s the real nappies that are more environmentally friendly, as you say. For one thing, they are not now filling up landfill sites; some of them are even still around, 20 plus years later, being used to mop up stuff.

tony () (URL)
5:59pm on 19 May 2005

We used real nappies with our daughter and found the whole process easy. She is now potty trained at two and a half. They were easy and efficient. One, of several, aspects the Environment Agency report missed was that a washable nappy lasts and lasts. A disposable is used ONCE. It’s crap. Literally. Try em!

Andy () (URL)
10:51pm on 30 December 2005