The participants' thermal comfort increased even in more extreme temperatures. Thus, the integration of a microforest, or densely vegetated spatial environment, in an office building can reduce building energy use, by allowing the temperature setpoint to be raised in the summer and lowered in the winter.
The results were based on a year long thermal comfort quasi experiment conducted in 2013 with approximately 70 office workers in The Netherlands, in which half of the participants had extensive vegetation in their workspace, while the other half didn't.
The operative temperature was varied throughout each testing period (one month per season). Plants were found to significantly improve occupant thermal comfort, including temperatures that were warmer and cooler than they were accustomed to.
The results of this research indicate that incorporating microforests into buildings not only reduces energy costs, but also can make the building more resilient to mechanical failures, peak loads, the effects of climate change, etc. Potential additional benefits include reducing mechanical equipment sizing, and increasing worker productivity and well being.