Energy saving is strongly affected by air leakages which also influence IAQ. Particularly, several studies show that the air-tightness energy losses contribution of the windows ranges up to 40%, with a value 15% higher than the one previewed by the ASHRAE. Such values confirm the high influence of the windows and the possibility to significantly reduce ventilation heat losses by only operating on the windows. Furthermore, inefficiency of windows is often combined with unsealed rolling-shutter boxes and with a bad mounting of the window. On the other hand, in the ventilation system design, air-tightness is generally neglected and included in the air change rate due to mechanical ventilation system. Such a practice increases energy consumptions and improves indoor air quality; on the contrary, a wrong assessment of the contribution of air infiltration can lead to the over-sizing of the ventilation system in the design phase. In order to better understand the influence of the windowed components on the air change rate under a pressure difference value of 50 Pa, class of air-tightness should be assessed for each tested component, in compliance with EN 12207 Standard and as a function of: (i) the type of material, (ii) the presence of the seal; (iii) the type of closure; (iv) the sealing of the door; (v) the maintenance condition. In this paper the Authors present the first experimental results of air-tightness measurements carried out in three residential buildings in which windows retrofit has been adopted in terms of sealing gasket on the wooden window and replacement with PVC or aluminium window). Moreover, the effectiveness of investigated windows retrofits has been estimated in terms of energy saving using the fan pressurization method. Obtained results showed a high variability of the air permeability although windows used for retrofit were characterized by lowest permeability values according to EN Standard 12207. This was mainly due to the poor care devoted during the windows installation and the lack of tests.
|Titolo:||Experimental analysys of different windows retrofit on building’s air-tightness: first results|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||4.1 Contributi in Atti di convegno|