Hi annelinor

Were your bills estimated previously? if they were this may be a catch up bill.

I'd speak to your supplier, you can ask for the Energy Efficiency department, they will be able to look at your usage and establish if there is a problem. They will be able to see where the energy is being used, I'd have a list of appliances and what you use to hand when you call.

I'd also ask if they have any better tariff for you, as you are on a pension or any further services or help that would be beneficial to you. Some times customers are entitled to things they just don't know about.

However small everything does help.