When to Replace Your Door Knob

Door knobs last 15 to 25 years in a typical home, though high-traffic doors (front entry, bathroom) wear out faster than bedroom or closet doors. The internal mechanism... a spring-loaded latch assembly... does the real work, and it is the first component to fail. Every time you turn the knob, a small spring compresses and releases to retract the latch bolt. After 100,000+ cycles (roughly 15 years of 20 uses per day), that spring loses tension and the knob starts to feel loose or fails to latch securely. There are 3 main types of door knobs. Passage knobs have no lock and are used for hallways and closets. Privacy knobs have a push-button or turn lock for bathrooms and bedrooms. Entry knobs have a keyed lock for exterior doors. Entry knobs see the most abuse from weather exposure and key insertion, so they tend to fail sooner at 10 to 15 years. The backset measurement is critical when buying a replacement. This is the distance from the edge of the door to the center of the knob hole. Standard backset sizes are 2-3/8 inches and 2-3/4 inches. Most replacement knobs include both backset plates in the box, but measure yours before ordering to avoid a trip back to the store. Many newer homes and commercial buildings use lever handles instead of round knobs. Levers are easier to operate with wet hands, full arms, or limited grip strength, and they meet ADA accessibility requirements. Round knobs do not comply with ADA standards because they require gripping and twisting. If you are updating knobs throughout a home, consider switching to levers for accessibility and convenience. Keyed-alike sets let you use the same key for every exterior door. Schlage and Kwikset both sell keyed-alike packages or offer rekeying kits ($10 to $15) that let you rekey all locks to match a single key.

Replacing a door knob takes 10 to 15 minutes with just a Phillips screwdriver. Remove the old knob by locating the mounting screws... on newer knobs, pop off the decorative rose plate to find them. Unscrew both sides, pull the knob halves apart, and slide out the latch assembly from the edge of the door.

Insert the new latch assembly into the door edge hole (bevel facing the direction the door closes). Set the exterior knob half through the latch, align the interior half, and tighten the mounting screws evenly. Test the knob before closing the door to make sure the latch retracts and extends smoothly.

If the existing strike plate does not align with the new latch, hold the door almost closed, mark where the latch contacts the frame, and reposition the strike plate. A chisel may be needed if the new plate is a different size than the old one.

For entry knobs with a keyed cylinder, the keyed side always faces the exterior. The thumb-turn side faces the interior. This seems obvious but about 10% of DIY installations get it backwards.

Pro tip: before buying, measure your door thickness. Standard interior doors are 1-3/8 inches thick. Standard exterior doors are 1-3/4 inches thick. Most knobs adjust to fit both, but some budget models only fit one size.