A lot of these companies, with financial backing from the government have been promoting the benefits of insulation and heat efficiently. Loft insulation, double glassing, cavity wall insulation and even central heating insulation have been given to those on low incomes or discounted to house holders. This makes the houses more efficient and therefore use less energy.
It is the mandate of the energy company's to flog energy. If there is a reduction in use of energy, you increase prices to maintain income levels, keep profit levels constant and please shareholders.
The winter fuel allowance is out, see other thread. So a vast amount of the population has an extra amount of cash to pay for the increase, even though some advocate they don't need the cash and will spend it on luxuries.
Where did I put my tin hat.