Phones have been running red hot at Heat Smart providers in Dunedin as people apply to warm up their homes.
The Government's Warm Up New Zealand: Heat Smart programme came into effect last Wednesday, and Craig Scoullar Electrical co-owner Becky Scoullar said the phones since then had been "overloaded".
Before the change, she had been answering up to 10 calls an hour; that had increased to a call a minute.
Most calls were going through to an answerphone and she, and a part-time staff member hired last week, had been working their way through them.
There was now a four-week wait for assessments and it could take up to eight weeks to have the insulation installed.
Suppliers had been struggling to meet demand, she said.
As well as inquiries for energy assessments, she had been fielding calls about prospective jobs from individuals and employment agencies.
Mrs Scoullar was confident no-one wanting to make the most of the scheme would miss out.
"It's a four-year scheme so you don't have to get in early," she said.
Davies Heat and Cool scheme co-ordinator Della Hopkins said the company had been "very busy" fielding calls and had also hired a new staff member.
Customers were experiencing a one- to two-week wait for assessments.
