Families are using nearly a quarter less energy than in 2005 as household efficiency measures and rising costs have taken effect.

The average home usage in England and Wales fell by 24.7% over the period to 2011, according to the Office for National Statistics (ONS).

The highest regional consumption levels, which were adjusted to take into account the variations in weather, were in the east Midlands, the data showed.

It appeared that regions with the highest level of Economy 7 consumption of night-time cheap electricity use more energy overall.

Across England and Wales, average household energy consumption fell from 26.2 megawatt hours (mWh) in 2005 to 19.7mWh in 2011.

Improvements such as better loft and cavity wall insulation as well as more efficient boilers may be among the reasons for the decrease, the ONS said.

Another could be the introduction of energy rating scales for properties and household appliances, allowing consumers to make informed choices about purchases, it added.

There has also been "increasing public awareness of energy consumption and environmental issues" while at the same time the price of gas and electricity across the UK has been rising.

The average household energy consumption in the east Midlands in 2011 was 27.5 mWh, well above the national average, while the south-west had the lowest, at 16.1 mWh.

A breakdown of local authorities showed that those consuming less energy tended to be in more rural areas, with a higher proportion of households without piped gas and therefore possibly using other sources of energy.

Of the 10 authorities with the lowest consumption, topped by the Isles of Scilly, eight included rural parts of Wales and the south-west, although two were in the capital – the City of London and Tower Hamlets.

The ONS said that areas that consumed more household energy tended to have higher levels of net income after taking account of housing costs.

All the top 10 areas for consumption were in the east Midlands, a region that had the second highest level of Economy 7 use as a proportion of all energy.

"It could be that households which receive some electricity at a cheaper rate may use more energy overall because it is cheaper," the ONS said.