Every January, our phones ring with the same chorus: keys that won't turn, deadbolts that won't throw, smart locks that died overnight. Winter is hard on locks — but almost all of it is preventable. Here's the seasonal playbook.
Frozen cylinders
Moisture gets into the cylinder, temperature drops, and your key meets ice. Prevention: a lock-specific de-icer/lubricant applied before the deep cold, and keeping the keyway covered on exposed doors. If it's already frozen, warm the key gently and insert it carefully, or use de-icer — never force it, and never pour hot water, which refreezes worse.
Doors that swell and shift
Wood moves with humidity and temperature. A door that latched perfectly in October may drag by January, throwing off the strike alignment until the deadbolt won't throw. This isn't a lock failure — it's a door-movement issue, fixed with strike adjustment or hinge tuning.
Smart locks in the cold
Batteries lose capacity in cold weather, and a lock on an exposed door works harder. Going into winter: fresh lithium batteries (they handle cold far better than alkaline), and keep the mechanical backup key somewhere accessible — not inside the apartment the lock guards.
The pre-winter check
October is ideal for a walk-through: test every deadbolt's full throw, lubricate cylinders properly, check strike alignment, replace batteries in electronic locks, and confirm weatherstripping isn't fighting the latch. Twenty minutes now beats a 2 a.m. lockout in a cold snap — though if that happens anyway, we're at (212) 671-0532, all winter long.