I've uncovered chilling new evidence about energy bills.
If your energy bill had come down in line with the drop in wholesale prices, you'd be better off by around £70.
It's one of the most startling facts to emerge from my investigation for ITV's Tonight programme Energy Bills - the Cold Facts.
The programme, which will be broadcast on ITV tonight at 7.30pm, shows the views of bosses whose companies have made millions from Britain's power industry - and also of families deep in fuel poverty.
I got access to new industry data and met with the Energy Secretary Ed Davey. And thanks to an experiment at the University of South Wales, I even suffered the effects of mild hyporthermia.
When I went to the university I didn't really know what to expect, I'd been told I would be part of a "cold house" experiment.
What greeted me was a small metal-clad room, which the experts could monitor constantly as the temperature was dropped to 12 degrees.
This was chosen to replicate what somebody in a cold UK home could experience. At regular intervals my blood pressure, core body temperature and mental agility were measured.
According to the NHS anything between 12 and 9 degrees increases your risk of cardiovascular diseases such as heart attacks - and by 5 degrees you are heading for hypothermia.
We'd intended for the experiment to run longer, but after five and half hours Professor Damian Bailey from the university decided we had to stop as I was showing signs of mild hyporthermia.
It left me feeling sad that some people will be living like that this winter. Home is where people should be able to feel safe and comfortable - but people in cold homes can’t feel that.
- See more about Chris's experience in the Cold House here
Britain's Competition and Markets Authority (CMA) is investigating whether the big energy firms are playing fair - but it will be a year before it reports.
Officials will examine the gap between the wholesale prices paid by power firms and the amount they take from us. This is something that is hard for customers to do for themselves.
As part of my research, I was allowed to join a trader who buys wholesale energy. He showed me how volatile the market is - if something happens to the climate or politics on the other side of the world it can have an almost immediate impact on prices.
He has a ringside seat on what is really going on - and he told me he thinks some people are not getting a fair deal. He says the wholesale prices he sees do not justify some of the prices he has seen been charged to customers.
We also had new analysis from industry experts. They told us that if the fall in wholesale costs over the last year had been passed through to bills, we would be on average £70 better off when paying gas and electricity combined.
When I put this to an energy company spokesperson she told me suppliers have to buy their power a long way in advance. This, she says, helps to smooth out the volatility of the market but makes companies less able to pass on short term drops in wholesale prices.
I put the same questions to the Energy Secretary Ed Davey and he told me he had supported the CMA 's investigation so that we can get in depth analysis on how Britain's energy market is working.
Our research shows that, as we enter the winter months, there is great mistrust and anxiety about energy companies.
A survey for the ITV documentary shows:
- Just one in three people, 34%, trust their energy supplier to charge a fair price
- 46% plan to cut back spending in other areas to pay their winter energy bills
- One in eight (13%) have had problems with their energy bills in the last year
(Source: Which?/ Populus Poll for ITV)
Watch Tonight: Energy Bills - the Cold Facts on ITV at 7.30pm.