Critical significance of attics and basements in the energy balance of twin rivers townhouses

After retrofitting of town houses at Twin Rivers it was found that heat loss from attics was much higher than predicted. This was accounted for by heat transfer within the wall dividing adjacent townhouses (party wall) from each other. This occurs both by conduction and by air movement through vertical holes in the party wall. Suggests that basement is thermally coupled to the attic and adjusts the model to allow for this, giving a three-zone model for the house