Smart Mortise Lock

Rather than boring holes through a door face, this style slides into a slim pocket routed into the door edge, called a mortise. One lock body holds the latch, the bolts and the cylinder together. Turning the handle upward throws two, three or five bolts into the frame at once on a multipoint version. Doors across Europe, much of Asia and the Australian market are built for it. The fittings run to different rules: euro-profile cylinders, a 92 mm or 85 mm hole spacing, and backsets stated in millimeters.

None of the North American styles will fit these doors. A Smart Deadbolt needs a 2-1/8 inch cross bore that a narrow aluminium or uPVC stile does not have. Against a Smart Lever Handle, the difference is decisive: several bolts biting along the full height of the door instead of one 1/2 inch latch. The trade is complexity, since the gearbox, the cylinder and the electronics are three parts that must match.

Apartment doors, French doors, patio doors and modern insulated entry doors are the natural homes for it. Buildings that already have multipoint hardware often need nothing more than a motorized cylinder or a new lock body, which keeps cost down. Avoid the format if you cannot identify your existing lock body precisely, because a wrong backset or spacing means the door has to be re-routed by a joiner.

Write down five measurements before you shop: backset, hole spacing between cylinder and handle, the faceplate width, the door thickness and the overall lock body height. Look for a cylinder with anti-snap and anti-drill protection, since a euro cylinder that snaps at the fixing screw is the known weak point on these doors. Confirm the lock still throws its bolts by handle when the power is gone, and that an internal handle always opens.

Grease the multipoint gearbox lightly once a year with the lubricant the maker names, and lift the handle every single time you close the door, because leaving the bolts unthrown is the mistake that lets a door warp. Adjust the keeps if the handle needs force. A gearbox that grinds is a repair to book now, not later.