KI's so-called barometer indicator rose to 107.1 in September, from 105.1 in August. This is the fifth consecutive month of increase for the indicator.
The household confidence indicator rose to 102.2, from 98.4 in August.
"Significantly improved mood among households," KI writes in a press release.
The report also shows positive signs from parts of the labour market.
"Expectations for the number of employees overall point to an increase in the workforce in the business sector over the next three months, but hiring plans differ between sectors. The plans are stronger than normal in the manufacturing industry and construction, but weaker than normal in trade," writes KI.
