Leicester-based Mark Group has announced that 670 of its staff will be made redundant and is blaming the effects of changes to the Energy Companies Obligation scheme for this.
The scheme was changed at short notice by the government at the end of last year, following widespread discussion on energy bills.
With a workforce of 2,500 in the UK, group is effectively reducing this total by nearly a quarter.
Mark Group chief commercial officer Bill Rumble told the Leicester Mercury: “This was an abrupt policy change by the government.
“It’s a fairly modest saving in energy bills we are talking about - £35 a year. If you have cavity wall insulation you could save £150 a year.
“The only way to reduce bills in the long term is to make homes more energy efficient,” he said.
Sustainable Energy Association chief executive Dave Sowden said: “These jobs are at risk as a direct result of short term changes in government policy, driven by hasty politics.
“As we head towards the election, it is crucial that energy efficiency is no longer used as a political football, and that party politics are removed from the equation.”
Mr Sowden stated that a stable, long term policy framework for energy efficiency is vital, referring to the SEA’s 2015 Manifesto, which urges all political parties to support its programme for change.