Seized & Jammed Lock Opening: preparing for the visit

It is the coldest morning of the winter and the key goes halfway into the side door and stops. There is frost on the face of the cylinder, and the door on the shaded side of the house has done this before.

Worth answering before the call

Is there another door you can use in the meantime? Has anyone sprayed oil or another product into the keyway? Which side of the building does the door face, and is it near a salted driveway?

My keypad deadbolt is jammed and the motor just whirs. Is that the same service?

Yes, with one difference. On an electronic deadbolt the motor is trying to throw a bolt that is bound in the strike, and it strains or times out instead of driving it. Door alignment is a common cause, though batteries, corrosion, an overtightened mounting bolt, or a hardware fault can produce the same strain. The locksmith frees the bolt, adjusts the strike or hinges so it travels without resistance, checks the battery contacts, and confirms the auto-lock throws cleanly with the door closed.

How do I stop this from happening again?

Three habits cover most of it. Lubricate the cylinder with a dry lock product twice a year and keep oils out of it. Check that the door locks with no pressure on it each spring and fall, snugging hinge and strike screws when it starts to drag. Keep a lock de-icer handy and fit a keyhole cover on exposed doors. And act on the first stiff turn, because a lock that still turns is a smaller job than one that has stopped.