# Washing Machine Cost Calculator: Notes and Caveats

This calculator was originally written for cloth nappy (diaper) users, in the UK. The values it works out will work for any washing machine user, though, working in any decimalised currency, assuming an inflation profile similar to the UK when assessing wear & tear costs. Your electricity or gas metres may not measure in relevant units, however; there are some notes below to help resolve that.

Not everyone uses fabric conditioner, sterilising powder, etc. Set these values to zero where appropriate.

A 30 degree C wash uses about 40% less energy (according to most Internet sources) than a 40 degree C wash (your washing machine manual may only tell you about energy usage for 40 degree washes). For instance, our machine uses 0.65 kWh for a 40 deg. wash, so about 0.39 kWh for a 30 deg. wash. Otherwise, where nappies are washed at 60 deg. C, the costs calculator assumes that a 60 deg. wash uses 266% more energy than a 30 deg. wash, or 160% more than a 40 deg. wash
That said, pence cost per unit (kWh) of electricity is about 10p in the UK (2010 price), but likely to rise fast. Going from 40 degrees to 30 degrees therefore saves a mere 2.6 pence in energy costs, for most people.
The best detergent price I can get is about 10pence/wash (year = 2010).

Other Info
You need to enter zeros for stuff that doesn't apply (like if you never use fabric conditioner).
The nappy questions are asking how often you need to wash nappies for each child -- so even if you have 2 children at once in nappies, you need to guestimate how often you would run the washing machine if only one was in cloth nappies.
Also assumed that each child in cloth for 2.5 yrs of their life. There is no facility to include tumble drying in this calculator, but you can easily figure it out by inputting the energy values as for a washing machine, and setting other variables (eg, for detergent) to zero.
Costs are in today's money (eg, year 2001).

#### Energy Usage

This is usually the largest portion of the overall washing costs.
Most gas metres give values in cubic feet; some may give units as cubic metres. The script assumes cubic feet, and to convert from m3 to feet3

#### Detergent

Most powder detergents are sold by weight (eg, kg), but come with dispenser containers that measure out by volume (ie, ml). I worked out the likely ratio between the two (will vary by particle density) by looking at two brands. (Persil Non Bio and Tesco's own), and their claims for how many washes a person could get from each box. The ratio seems to be about 1.64 -- ie, 100 ml of powder is approx. 61 g of powder.

#### Wear and Tear

This is easily the biggest fudge of the entire worksheet. Note I only allowed for one repair cost entry. Wisest to choose the largest repair bills you've had for input. Costs worked out with inflation assumed to be (per annum) 5.675% from 1981-1989; and 2.9% for 1990-present. Source: www.globalindata.com.

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