End-of-terrace house
Energy label for an end-of-terrace house
An end-of-terrace house has one more external wall than a mid-terrace house, and that wall does most of the work in the calculation.
The additional side facade increases the surface through which heat is lost. Whether that leads to a worse label depends entirely on how well that wall is insulated.
The side wall
In houses built before the 1970s the side wall is often the least insulated part of the property, because it was added as a boundary wall rather than designed as a facade. Cavity wall insulation applied later usually improves the result significantly, provided it can be evidenced.
Also relevant
Windows in the side wall, which are common and often single glazed
Extensions built against the side wall
The roof, which is usually shared in construction with the neighbours
Exposure to wind and driving rain on the free side