All windows and doors utilised in Passivhaus certified buildings have to meet certain performance criteria. The wall openings have been discussed in the previous diary entry but here we will detail the exact capabilities of the window and doors units. Windows and doors can never be as well insulated as the rest of the building envelope, but the right design and appropriate positioning will maintain the passive house performance. There are no traditional external doors used in this build, all the doors comprise of fully glazed panels, essentially oversized window units. These high performance door units facilitate additional solar gains from the south facing elevation.
All the windows and doors were supplied by Munster Joinery/Baskil Window Systems. All the windows and doors have been certified by the Passivhaus Institut in Germany, assuring they meet the requirements necessary for Passivhaus certification and insuring their performance capabilities.
Again the windows and doors have been modelled using PHPP software to analyse their performance. All windows and doors must perform as part of the overall building envelope and must achieve a total U-value equal or below 0.8W/(m2K). In our build the windows and doors achieve a U-value of 0.77Wm2K (and a glazing U-value of 0.6 Wm2K).The glazing has a thickness of 52mm and the cavities are argon filled.
The frames are all grey finished PVC with easy clean friction hinges. All ironmongery is brushed satin finished aluminium.
The windows and doors are also positioned as far forward within the opening as possible to maximise the solar gain capabilities of the glazing. The finished openings will look fairly traditional, externally surrounded by render and in some cases timber cladding.
This photograph illustrates two of the windows in-situ with the external timber cladding fitted.