Entry transition / thermal buffer spaces (unconditioned buffer zones e.g. north-facing utility rooms; solar buffer spaces e.g. south-facing attached sunspace/greenhouse)

Solutions

• South-facing attached sunspace / solar greenhouse: Glazed buffer capturing solar heat, distinct from a north buffer, can offset a large share of heating demand.
• North-facing unheated utility buffer room: Unglazed garage/pantry/hallway acting as an insulating layer against the cold side, not a solar collector.