What Most People Get Wrong
The common move is to add weatherstripping and call it solved. New bottom seal, new side seals, maybe some foam tape around the top panel - and the draft is still there because the panel itself has no insulation value, just steel. Weatherstripping stops air leaking around the door. It does nothing for the door conducting cold straight through the metal. The other mistake is assuming any retrofit insulation kit will bring an old door up to modern standards. Here's the honest limitation: foam board glued into the back of a door built in 1968 adds some value, but it's not close to what a true insulated door with a thermal break delivers, and it won't fix a door that's already racked, bowed, or running on dead springs. If the door is old enough to be original to a 1960s or 70s build, insulation retrofit is a stopgap, not a fix. Sometimes it's the right stopgap - a tight budget year, a door that's otherwise sound. Sometimes you're better off putting that money toward replacement instead of improving a door that's going to need replacing in a few years regardless.
How Local Conditions Play In
Cold, severe winters do specific things to a door built before insulation rules existed. Steel contracts in the cold, so an uninsulated panel that fit tight in August can develop gaps by January - gaps that let in both air and moisture. That moisture condenses on the warmer inside face of the panel, and over enough winters that's where you get rust starting at the bottom corners, right where the door meets the slab. Torsion springs also see more cycles of extreme tension change in a cold climate than they would somewhere milder, because cold steel is less forgiving under load, which shortens spring life on doors that are already decades old. Across the service area's 27,559 owner-occupied houses, a door built during that same 1945-to-1994 stretch is often doing double duty as the only insulated barrier between an unheated garage and a Michigan winter, whether the original owner thought about it that way or not. With median household income here at $75,707, a lot of owners are weighing a modest weatherstrip fix against a full insulated replacement, and the math isn't obvious either way - it depends on the door's actual condition, not just its age.
