Goings-ons with the ESB bill

We recently moved. Now, part of the process of moving is that on your last day, you take your final ESB reading, and tell them about it, then pay the remaining balance immediately. In theory, they would like you to move the account to your new place, but in practice this would require you to move out of the old place at the latest the day you move into the new place, so doesn't seem practical.

So, I gave the ESB the latest reading, and was told 'oh, you're in credit for LARGE_AMOUNT; we'll send you a cheque'.

It turned out that they'd been running on estimates of what our usage was, rather than actually reading the meter, for some time. The daytime electricity usage lined up, more or less, but they had massively overestimated nighttime usage... that is, the electricity for the storage heater. In fact, it seemed that we'd been on estimates since probably early this year.

Of course, early this year, it was cold, and we were using storage heaters a good bit. Shockingly, however, we were not using storage heaters all the time all through the summer. It would seem that their estimation procedure doesn't take this into account.

Now, we used to live in a small building, and I suppose it was a good bit of trouble for them to check all the time, but I can't help wondering a bit (because I'm a little paranoid) whether it's entirely accidental that they did proper readings when it was cold and then based estimates off them when it was warm. This basically amounts to an interest-free loan for them; they do eventually give the over-estimate back, but of course they don't pay interest on it. I'm sure it's entirely accidental, but it does work in their favour.

At any rate, it seems a bit crazy that they'd take estimates for a night-time meter (pretty much only used for storage heaters and the like, in most places) at a cold time, and expect usage to be the same in a warm time. Silly ESB!