"It was obvious that he is doing all he can to benefit the end consumer," Mr Winitana said.
Mr Duncan said winning the person of the year award was "really out of left field", with candidates chosen by judges.
The awards were held as part of the association's annual conference, named The Power Shift, that focused on how demand from households and businesses for energy independence was driving new technologies and business models.
Mr Duncan said the conference name was because the solar industry was changing how electricity was being bought and sold.
"Demand management and storage batteries allow a customer to manage their own energy consumption," he said.
"Peer-to-peer power allows a solar customer, or what we call a prosumer, to nominate someone else to benefit from the solar power they do not consume.
"It's like an internet of power. It is a very exciting time to be involved in this industry."
The Duncans set up Freenergy nine years ago, and the four-person business provides solar power, hot water heating and pool-heating systems.
Judges noted Freenergy's sales were "streets ahead" the national average.
"We entered the awards to benchmark ourselves against our peers," Mrs Duncan said.
"We wanted to showcase the variety of residential, business, rural, education and community housing projects we are undertaking, and the different applications."
The small business award confirmed Freenergy's customer focus "and passion to keep up with the technology in this constantly evolving industry".
It is another boost to the local industry following a recent Advertising Standards Authority (ASA) decision.
Hawke's Bay solar power companies strongly supported Greenpeace's use of the word "tax" to describe Unison Networks' increased line charges for solar power generators.
Unison said it was unfair the generators paid little on lines charges, because when they did use Unison's service it was at peak times.
Following a complaint the word "tax" was misrepresentative the ASA ruled although Unison's solar charge increase did not fit the legal definition of tax it could be considered appropriate because the charges were compulsory.
