Judge Ian Mill said the dissemination of information was "significant and significantly inaccurate".
"All the facts must have been known to the defendant company including the limitation of the test results."
Commissioner Anna Rawlings said the conduct involved bold claims about superiority and energy efficiency, made in persuasive terms by a well-known and reputable manufacturer.
"Claims about efficiency are important to consumers who may be cost-conscious but also concerned about the environment. The efficiency of these heat-pumps was represented as a key selling feature, but without a proper scientific foundation for the claims," she said.
Fujitsu is the first company convicted and fined under the unsubstantiated representations provision of the FTA, which came into force in 2014.