In our sample, the picture on the left shows ratings for the existing house, in the centre with added insulation and on the right with insulation and double glazing. All areas show steady improvement except the passage/entrance area. This is most likely because the two changes have very little impact on the passage, there is no external walls to speak of and no windows.
We could then look at other ways to improve the performance in this area, like zoning. A door separating the entrance from the passage at the back and doors on each side of the living room, currently permanent openings, could improve the performance in both areas.