Energy bills from the cold snap will bite

If the temperatures weren't enough to make you shiver, the extra costs from cranking up the heating may do. Centrica, the owner of British Gas, the biggest household supplier revealed today that its customers turned up the heat so much during this year's cold winter that they used 18% more gas between January and April. That will add on average, another £40 to customers' bills.

But the company has also made an interesting announcement promising that any increase in profit they make, due to the increase in consumption, will be used to keep future price rises down, rather than going back to shareholders or being spent on anything else. What they will not say is for how long they'll be able to freeze prices.

It is not clear therefore how much faith you can actually have in the promise. British Gas prices went up last autumn by 6% and today they are already charging more than their competitors on some deals. The comparison site, Uswitch, told me that today British Gas is the most expensive gas supplier for the average user with a bill of £842 a year, compared to the average of £799.

But the move certainly lays down a challenge to other big energy companies who will be revealing how they did in the next few weeks. Today they were tight lipped on whether they might follow. One source said, 'it's very brave', but another said, 'we already postpone price rises as long as possible.' It is perhaps brave because there are many parts of the energy bill, wholesale costs, and government charges that companies cannot control.

And it does mean that the company won't be able to use the explanation for any controversial rise in profits this year next time round. In February, when the company's annual results showed an increase of 9% in profits for 2012 for British Gas, the Chief Executive, Sam Laidlaw told me:

Having made this promise today, that line next year will not wash. But the move does set Centrica apart from one of their rivals, Eon, who has already revealed their results for the first three months of the year. Just as couple of days ago they report that consumption had gone up by 15%, and their profits went up too.