So, then, your anecdote completely exemplifies OP&#x27;s thesis: a house double the size and much more efficient uses the same energy. Vive la différence?<p>You also mention foam filling, and by proxy, sealing. Many high efficiency homes achieve their efficiency by becoming effectively Tupperware® containers. Which isn&#x27;t good for the occupants (unless living in Mordor is a goal). Air exchangers are required, muting the gains on efficiency.