Bit of a real-world problem here.
My current electricity supplier charges me 195p per week as a fixed-cost service charge. They charge me 15.91p per kWh at high-rate hours and 8.75p per kWh at low-rate hours.
Or you could say that my weekly cost is:
A potential electricity supplier would charge me 175p per week as a fixed-cost service charge. They would charge me 11.654p per kWh at all times, with no low rate hours.
Or you could say:
So my problem is... which supplier would give me the best deal?
Now, I don't know precisely how much energy I use in the low rate hours and how much I use in the high rate hours, but there's only really 4 things that we use specifically in the low rate hours (washing machine, dishwasher, tumbledryer, heating, etc) under supplier 1, and the rest (laptops, lights, TV, phone chagers, hairdryer, hair straighteners, cooker, fridge, freezer, water heating, alarm clock) is in the high rate hours, so I have something of an inkling which suggests that most of hour useage is in the high-rate hours.
However, what I'd like to know is precisely which ratios of give , so I can more accurately estimate whether I'm better off switching or staying.