I have a question regarding envelope U-values for ID+C scheme when following whole building energy simulation option. The project we are working on consists on a fit-out of 4 office floors within an existing envelope which was not renovated (no alterations to the existing external fabric). The poposed roof U-value is approx. 0.60 W/m2K which is much higher than the value of 0,273 W/m2K prescribed by table 5.5 for 3C climate. Can we still follow whole building energy simulation option based on app. G, or as this is a mandatory provision we do not have that option? If not, how should we proceed for this prerequisite? All the remaining building data (Lighting, mechanical equipment, etc.) is efficient and complies with ASHRAE 90.1, and the proposed building show improved performance when compared to the baseline per app. G.
Thank you all.