This energy retrofit focused on improving energy efficiency and thermal comfort. Before the reno, the homeowners would sleep by the living room gas fireplace in winter because the rest of the house was so cold. Wall cavities were completely un-insulated and plumbing was freezing inside the floors. The retrofit involved inserting blown-in, dense-packed cellulose insulation through small holes cut into the drywall, for minimal disturbance. Joist ends received closed-cell spray foam insulation, and mineral wool batts were added to the shared party-wall, to reduce sound transfer and improve the fire separation. A spot ERV was installed in the bathroom to exchange both fresh air and heat. All work was completed with minimal disruption to the existing finishes.