How we came to our numbers

• Costs are all directly taken from retail prices at local Woolworths supermarket, August 2008. Range of prices and averages are shown. Totals only reflect average cost.

• Cloth nappy prices are based on purchase of an all in one pack, plus additional liners.

• Disposable wipes are retail prices as above and worked out to be 8.3 cents each (range 6.8 - 17 cents). Presumed that only one wipe is used per change.

Additional to costs or purchase for cloth nappies is the cost of washing and drying.

Breakdown costs are considered below and the laundering cost per change is calculated by dividing the total laundering cost by total number of nappy changes over 30 months. Laundering cost includes 100% use of clothes drier.

• Washing Machine: usage calculated on doing full wash in 4-5kg sized average machine, using 0.95 units of electricity per wash.

• Clothes Dryer: usage calculated on full load (4-5kg dry weight) for average machine, dried at full heat uses 3.35 units of electricity per load.

• Washing Detergent based on using 1/2 recommended amount per wash giving 20 washes per 1kg concentrate (50g per 1/2 scoop). Figures in brackets indicate cost for using Napisan only (50g equal to one capful as recommended) at 40 washes per 2kg container. Totals only reflect use of washing powder.

• Costs or washing powder average within range of local Countdown supermarket, February 2008. Average cost $4.91/1kg concentrate (range $3.99 - 5.96).

• Electricity costs based on most expensive rate for Meridian Energy (as at September 2003) of 17.54 cents per kWh.

• Wear and tear based on replacing washing machine and drier completely after 10 years, with a total combined cost of $995, with 30% total machine usage dedicated to nappy washing. Assumes use of drier 100% of time.

• Water charges have not been considered as water use is not charge for in this part of the country.