On 2007-10-07 23:24:12 +0100, Mike Barnes said:

Sainsbury's online has own-brand powder at £5.49 for 3 kg, which works
out at 4.5p per 25g dose. The cheapest tablet (Finish All In One x42
Introductory offer £5.00) works out at 11p per dose: nearly two and half
times as much.


To make a fair comparison, one would also have to include the costs of
rinse aid and salt, although the cost of the latter is not significant
unless you buy the small packages of dishwasher salt rather than 25kg
bags. Finish Rinse Aid at £1.70 for 250ml. If that covers 50 washes,
which is generous, that's another 3.5p per wash, plus salt, say 4p.
So really the comparison is more like 9p vs 11p.

Don't forget also that there's around 10-15p in electricity cost per
cycle as well plus depreciation (average £400/5 yr/1 load a day) = 33p
a wash.

Then the saving is really 2p in 44p or about 4.5%.

Ergo, if you really want to save money, the way to do it is not to have
a dishwasher at all.