In 1990, Quinn Evans Architects led the comprehensive restoration of a then 90-year-old Carnegie Library. 'Sustainability' was not much of a buzzword yet, but its historic window sashes were retrofitted to accept insulated glazing, its cold attic was insulated, and a non-original lay-in ceiling was removed to expose the dome and lay light above, once again letting the clerestory daylight fill the central space. A sizable addition to the library included fluorescent lighting, cavity insulation, double-pane glazing, and sun-filled walkways connecting the historic and modern wings. 25 years later, we are back! Tired mechanical units, roof leaks, and worn interior finishes instigated a timely renovation. But 25 years wiser and more technologically advanced, we don't just 'replace'; we 'refresh' and 'layer' with sustainable sophistication. - Now we still insulate, but we understand the benefits of a higher R-value. Modern spray foams allow us to virtually eliminate the negative effects of air infiltration. We can model and analyze assemblies during design, to avoid pitfalls with mold and moisture. - We still mechanically condition the space, but now we have high-efficiency units. We can layer on Building Management Systems with smart, programmable, and integrated controls that the client can adjust and monitor from their own computer screens. A process called commissioning helps us fine tune installations to actually meet performance expectations. - Now we replace fluorescent bulbs with LEDs. We add occupancy sensors so the lights are only on when we need them. We can even let the sunlight directly adjust the lighting automatically. - We may replace and refresh outdated finishes, but now we can recycle those worn materials so they can become something new. We demand new finishes are modular, durable, local, and less toxic. Quinn Evans was at the forefront of sustainable design then. We have sharpened our green pencils now. And sometimes…we even get to come back to where we have already been, and add new and improved layer to the sustainable story.