Washington - Low income families have been forced to cut back on basic purchases like food and medicine and keep their homes dangerously cold or hot as a result of surging energy prices in the United States, according to a national survey released Wednesday.

But the high cost of petrol, heating and air conditioning is also spurring efficiency across the country as even wealthier consumers said they were driving less, buying smaller cars, using public transport and installing more efficient appliances in their homes.

Sixty-five per cent of lower-income households said they had cut back on basic necessities and 31 per cent said they were forced to maintain unsafe temperatures in their homes, according to the survey conducted by the National Energy Assistance Directors' Association (NEADA).

The actions have prompted states to call for greater federal funding for energy assistance programmes to help families cope and to pay for costly home upgrades that could boost efficiency.

Home heating oil prices have increased by about 40 per cent in the past year. Petrol prices have risen about one-third to nearly 1 dollar per litre - still well below petrol costs in Europe.

That meant the average family paid about 1,500 dollars more per year in petrol costs alone, according to Mark Wolfe, executive director of the NEADA.

While better-off households could pay for energy-efficient measures that help reduce costs, such as new cars, there are few cheap upgrades available for already struggling families, according to state officials who commented on the survey.

Jerry McKim, head of Iowa's Bureau of Energy Assistance warned that the energy crisis had turned into a "public health matter" as families were making dangerous cutbacks in essentials.

Nearly 60 per cent of low-income households - those with incomes below 25,000 dollars - said increased home energy and petrol costs had a "large impact" on their confidence about the future, according to the survey. (dpa)