In the first four months 19,759 homes have been retrofitted under the scheme. The scheme's original target was to see 27,000 homes insulated in the first year, but Energy and Resources Minister Gerry Brownlee believes the target will be met after only six months.

"Demand for the programme has been huge in the first four months," he said.

To continue the momentum and address demand, the scheme will change to a multi-year appropriation, allowing funding to be brought forward to withstand demand.

By allowing the scheme to become a multi-year appropriation a steady stream of funding will be on tap to keep the momentum rolling," Brownlee said.

There were 5,720 homes retro-fitted in October, with a considerable number occupied by low income earners, which Brownlee believes is a very positive trend.

"The scheme is reaching those most in need and least able to make the changes themselves."

The Green Party is also welcoming changes to the insulation scheme, which is a Green Party initiative.

"It makes sense to improve as many homes as well can as fast as we can," Green co-leader Jeanette Fitzsimons said.

"We'll get the money we spend through better use of energy resources and a better health for the New Zealanders who live in these homes."

Fitzsimons also praised landlords who had taken up the scheme to support their low-income tenants.

"I'd like to congratulate the landlords who have taken up the scheme to improve the living conditions for their tenants," she said.