A new report has found Government vastly overestimated the cost of new home insulation standards

Building and Construction Minister Chris Penk is considering rolling back the H1 insulation requirements brought in last year - amid reports they add up to 40-thousand-dollars to build costs.

But research by New Zealand Certified Builders and others, shows the requirements can add as little as two thousand 200-dollars to the cost of a three-bedroom house.

Research author Nick Clements says the Government's approach looked at the very maximum, which isn't realistic.

He says they instead looked at the minimum they could do to meet the standard.