On Mon, 01 Mar 2004 17:39:04 +0000 (GMT), Dave Liquorice wrote:

snip

All depends on the tariff you have. See T i m ' s post about
variations in tariffs. It really is a nightmare now and you have to
know your actual consumption at the proposed peak/off peak hours to
come to any sensible conclusions.

There certainly are tariffs about that float the 7 hours within a
window, or split it within a single nighttime window. There are others
that give you 5 hrs in a night window and another two in an afternoon
window. Standing charges may or may not(*) exist, be more or less than
the normal domestic tariff.

(*) Though they normally they claw that back by charging you more for
the first X units each quarter. So it's just marketing puff, no real
saving to the consumer.

Oh, there is a real saving to the customer if he or she has a whacking
great load that can be restricted to the cheap period. I have an 18kw
pool heater and running that at just under 3p per unit is *much* cheaper
than at 8 or 9p per unit!

When E7 was the only day/night tariff, as distinct from the variety of
time of day tariffs now available, the rule of thumb break-even point
was for more than 27% (If I remember correctly!) of unit consumption to
occur during the cheap rate period. The other thing, of course, was that
the night rate unit charge was the same across the country
pre-privatisation. Whether that's still the case I can't be bothered to
research