requie formual based on times.

[SS]

I am trying to work out the cost of running an aircon unit.
The electricity costs are different during the 24 hour day.

In cell C7 I have costs per KW from 06.59- 12.00am (lets say .30 p an
hour)
In cell C8 I have costs from 12.01-22.59pm (lets say
..40p per hour)
In cell C9 I have costs for 23.00 - 06.58am (lets say
..50p per hour)

In cell C11 I have time aircon switched on
In cell C12 I have time aircon switched off

In cell C15 I want a formula to put the total running cost for the period it
is used.

So, for example the aircon is switched on at 10.00 am and off at 24.00 pm

The formula C15 would have to work out 2 hours at .30p per hour, 11 hours
at .40p per hour, 1 hour at .50 per hour

Is it possible to do this?

thanks

 

[Bob Phillips]

Try this

=(("12:00"-MAX(C11,--"7:00"))*0.3+(MAX("23:00",C11)-MAX(C11,"12:00"))*0.4+(C12-MIN(C12,"23:00"))*0.5)*24