The application of Circular Economy to construction sector is a key to attain carbon neutrality

since it is responsible of 40 % of natural resource consumption. In this frame the importance of an efficient building refurbishment process throughout recycled material and renewable energy is fundamental. From an overview about building refurbishment emerges the need to investigate aspects related to Indoor Environmental Quality and the comparison between in-field measurements with output of dynamic simulation models. The present study aims to fill these two gaps by means an energy renovation of two real buildings in Greece. The work develops within the European project “Drive 0″

born to promote deep environmentally friendly retrofitting by means of circular renovation concepts. The methodological approach involves on-site monitoring of a series of parameters describing the energy

microclimate environmental and air quality

before and after the energy requalification. In addition

a numerical model developed in Building Energy Simulation program is calibrated and a Computational Fluid Dynamics is developed. From the in-field measurements emerges that

on one hand

the refurbishment of heating system shows a great improvement of indoor thermal conditions

with Total Volatile Organic Compounds concentration that sometimes exceed 3.0 mg/m

3

; on the other

hand an integrated thermal insulation reduces infiltrations and changes the envelope behaviour

with a global energy saving of 30 % during winter and autumn periods.Another result of the study shows that a numerical model developed in Building Energy Simulation program and calibrated on energy consumption can greatly fit the local thermal comfort distribution of the occupant zone and predict the indoor air quality

if it outputs are used as input data in a Computational Fluid Dynamics study. These results can be beneficial to decision makers and designers for evaluating emitters positioning

opening design and mechanical ventilation strategies

aimed at reducing energy costs.