AS THE days grow shorter and colder it is time to take a long, hard look at the cost of heating your home.

With predictions of Siberian conditions this winter, could you cut your fuel bills by switching supplier? Ofgem, the energy regulator, says that almost 50 per cent of electricity and gas consumers have never moved supplier and may be paying over the odds. The price comparison service uSwitch reckons that consumers who are still with their original supplier can make average savings of £140 a year by taking one of the better deals on offer. So the 12.5 million households who have yet to switch could save an estimated £1.75 billion a year.

But it’s not just on energy costs that customers may be losing out. They may be paying too much to repair or replace existing heating systems. Times Money has uncovered evidence that British Gas is still putting undue pressure on customers to agree to purchase new boilers or central heating systems despite assurances given three years ago when we first investigated these abuses. This coincides with a British Gas advertising campaign to win back customers who have gone elsewhere.

In January 2002 we revealed that British Gas was using high-pressure sales tactics to coerce customers into buying expensive new boilers and heating systems. After our disclosures British Gas said that it was tightening the way that it monitored its system.

We found that some British Gas engineers carrying out routine maintenance work in people’s homes were condemning their boilers as unfit when they were still serviceable. They would then call in commission-hungry salesmen to push for a quick decision on installing new equipment. If a customer agreed a deal, both the engineer and salesman would benefit financially. Some British Gas customers were persuaded to pay thousands of pounds for new heating systems when their old systems were perfectly adequate.

When a British Gas engineer turned up at my home this month to service the central heating boiler he condemned it as unfit. When I said I wanted a second opinion (by which I meant an independent second opinion) he called in a colleague who confirmed his diagnosis.

They then shut off the boiler, leaving me with no alternative form of heating, attached a warning notice to the equipment and declared that it should not, under any circumstances, be touched.

Their verdict on the boiler may have been correct, but I felt that I was left with no way of obtaining a second opinion since the key test to determine the boiler’s adequacy involved having it running. But restarting the boiler would have meant contravening the “no-touch” instruction. With the prospect of many chilly late autumn days ahead, I felt obliged to take up the engineers’ offer of a visit from a British Gas sales adviser.

Keith Kirby, the adviser, turned up two days later. After he had decided that the boiler would have to be sited in my kitchen, I asked him to give me a quote based on what we had discussed. He insisted on taking a £100 deposit as part of an order before he would work out what the cost would be.

When I protested, Mr Kirby replied: “We do not negotiate.” I said that this would not make a promising mission statement for British Gas. In an attempt to soften the blow he added that I would not be committing myself irrevocably to the agreement since I would have seven days’ grace to cancel the contract.

I reluctantly paid the deposit, after which Mr Kirby produced a detailed specification for the job. The total cost for installing the new boiler was more than £2,700. I cancelled the contract the next day. I have since obtained a quotation from a long-established and reputable firm. This quotation was £600 cheaper.

Times Money asked British Gas if it felt that it was doing enough to make customers aware that, before having their heating system scrapped, they were entitled to a second opinion from an independent Corgi-registered engineer who could override the stark “do not touch” warning notice. A British Gas spokeswoman says that the owner of any boiler classified as unsafe is given a letter stating that anyone else carrying out work on the boiler has to be Corgi-registered.

We also asked whether it was company policy for British Gas sales advisers to insist on a £100 deposit before providing a costing for a job.

The spokeswoman says: “We do not expect customers to provide a deposit before they have had a full quotation, including a final cost of the work to be carried out. If this is what happened in this case, then the issue will be taken up with the individual engineer because the customer clearly has not received the level of service that we would expect.”

She also confirmed that engineers receive a bonus of up to £10 for each customer referred to a sales adviser and that a sales adviser working to target would earn approximately 1.75 per cent of the revenue generated.

What experiences of pricing and service have you had from British Gas ? Let us know by e-mailing Times Online here .