Only four people have so far signed up to a flagship government scheme to make homes more energy-efficient.
The Green Deal, which was launched six months ago, was designed to provide measures such as home insulation.
The Department for Energy and Climate Change (DECC) said just four households have "pending" green deal plans.
However, DECC said that with more finance providers in place, it expected a steady rise in numbers.
In total it said there had been 38,259 Green Deal assessments, where customers are given initial advice about what energy improvements they might be eligible for.
Of those, 241 households have confirmed they would like to proceed with work.
A spokesman for DECC told the BBC that "some" of the four people who have signed up to the Green Deal will have had building work completed, but he was not able to be more precise.
"A slow start should have been expected for the Green Deal, but it has clearly not fired consumers' imaginations," said Mike O'Connor of the watchdog Consumer Futures.
The government said there had been a delay in getting finance providers approved, with only five lenders signed up so far.
"The very first wave of Green Deal finance providers have only just got their individual finance terms and conditions in place," said Greg Barker, Minister for Energy and Climate Change.
But he said he expected 50 loan providers to be approved by the end of the year.
"It will take time as this brand-new market finds its legs, but I now expect the number of plans signed to start steadily rising," he said.
But Labour said the figures were proof that the scheme was not working.
"The Green Deal was billed as the biggest home improvements programme since World War 2, but these figures show it is failing," said Luciana Berger, shadow minister for energy and climate change.
"Households need help with their energy bills now - not in 10 years' time," she added.
Under the Green Deal, householders take out loans to finance improvements such as double-glazing, or more efficient boilers.
The idea is that the energy savings they make should more than compensate for the repayments.
The loan remains with the property, not the individual.