Buyers' repair bills go through the leaking roof

House-hunting? Then look out for rusty boilers and rotting windows, warns Jasmine Birtles

Spring, the most popular time for house-hunting, is almost upon us, which is good news for those trying to sell a property. But buyers should beware that, in their eagerness to move, they don't overlook potentially expensive problems that could cost a small fortune to rectify.

Among the faults regularly overlooked by those who think they've found the home of their dreams are inadequate insulation, a dodgy boiler, rotting windows or an ancient central heating system. Research from the Energy Saving Trust (EST) reveals that every year in the UK £1.25bn is spent on unexpected repairs by people who have just moved house.

According to the EST's report, more than a third of buyers in the UK are paying an average of £2,500 on top of the purchase price of their new home because they are not aware of what they should be looking for when they are house-hunting.

Old windows and boilers are proving to be the biggest problems, costing home-buyers an annual total of £439m and £228m respectively to replace.

"Our survey shows that warmth is a top requirement when purchasing a new home, so we are encouraging people to look out for cavity wall and loft insulation, as well as condensing boilers, which will not only make for a cosy abode but also save on heating bills," says Philip Sellwood, chief executive of the EST.

Another common problem faced by homeowners is the need to replace damaged plasterwork and repair leaking roofs. Inadequate insulation and rising damp also lie in wait for the unwary.

Kate Rogers bought her home in Hastings, East Sussex, only last November. But already she is facing a bill of at least £2,500 to replace a 25-year-old boiler and thermostat. This was totally unexpected and unbudgeted for.

"I suppose I was so excited by the fact this place had an enormous garden that I didn't really pay attention to boring things like the state of the old boiler," says Ms Rogers. "I knew it was old, but it seemed all right at the time. However, I have a contract with British Gas and when they came over to check it out, they just laughed. The whole heating system has to be overhauled.

"Had I spotted the problem before I bought the house, I might have been able to negotiate on the price, because it was on the market for a long time."

But whether or not you can negotiate with the vendor in this way will depend on the value of the property you are hoping to buy and how desperate the vendor is to sell.

"If the property is in the £400,000 plus range, it's unlikely a dodgy boiler or some draughty windows will make a difference to the price," says Rose Lock of estate agents FPD Savills.

"However, I know from my experience of selling properties at the lower end of the market that buyers could quite frequently renegotiate the price, as they couldn't afford a whole new heating system."

Ms Lock points out that in order to negotiate successfully, you must obtain a report by a professional surveyor or another specialist indicating that substantial work needs doing to the property.

According to the Royal Institute of Chartered Surveyors, a homebuyer's report or comprehensive buildings survey will identify a boiler that might need attention or a heating system that looks as if it is on its last legs. But the surveyor will not check the appliance personally. Instead, he or she will recommend that it is inspected by a specialist, who will be able to give you an estimate for repair costs.

It is definitely worth negotiating on the price of the property if a survey reveals serious defects. Cara Franklin and her architect husband Frank Amankwah managed to slice £9,000 off the asking price of their £285,000 home in Berkhamsted, Hertfordshire. Like Ms Rogers, they bought their home last November.

"We could see from the start that the kitchen, including the old boiler, would need to be replaced, so we offered £7,000 below the asking price, which the vendor accepted," explains Ms Franklin.

"But when the full survey came back, we found there was also wet rot, rising damp, woodworm and problems with the roof, so we managed to get another £2,000 taken off the price."

Now, three months later, the couple estimate it will cost around £7,000 to make good these problems.

"It means we'll end up paying almost the [equivalent of the] asking price," says Ms Franklin, "but at least we know we haven't had to pay over the odds."

The Energy Savings Trust has produced a free homebuyers' checklist, giving advice to new buyers on what to look out for. To obtain one, visit www.saveenergy.co.uk/homebuyers or call 0845 727 7200.