Your front door can close and latch while leaving a weak seal along part of the frame. A dollar bill offers a low-tech way to check that contact: close it between the door and frame, then see how much resistance you feel when you pull. A loose section gives you a place to investigate rather than proof that the entire door needs replacing.
My Florida Home Energy’s weatherization guide describes the bill test for doors and windows and advises repairing or replacing weatherstripping where the bill slips out with little resistance. The test is a starting point, not a measurement of air leakage or a guarantee of lower bills.
Compare several points on the same door
Place the bill where the door compresses against its seal, close the door in its normal latched position, and pull without tearing the paper. Repeat around the sides and top, noting where resistance changes. Keep fingers clear of the closing edge and do not force a door that is sticking.
Look at each weak location while the door is open. Is a section of the seal missing, flattened, loose, or painted over? Does the door make consistent contact with the frame? Recording those details helps distinguish a worn seal from a door that is out of alignment.
Match the repair to the moving joint
Weatherstripping belongs at a joint that needs to open and close. Caulk serves a different purpose at suitable fixed gaps. Do not seal a moving edge shut because a bead of caulk looks easier than identifying the right replacement part.
Choose the seal by the door manufacturer’s guidance and the gap it must accommodate. A thick strip that prevents the latch from engaging is not an improvement. After fitting it, check that the door opens, closes, and locks without extra force, then repeat the contact check.
Check the bottom as a separate area
The sweep and threshold at the bottom of an exterior door need their own inspection. Look for damage and uneven contact, but avoid buying a generic strip before checking the existing assembly. Some doors use a replaceable insert or an adjustable component with specific instructions.
Persistent drafts can come from more than the visible seal. Vermont Energy Saver explains air sealing as work on the building envelope, with materials chosen for each location. A broader energy assessment can be more useful when several rooms remain uncomfortable after a simple door repair.
Do not block designed ventilation or alter a fire-rated door assembly with improvised materials. The aim of this check is a working door with an appropriate seal, not maximum resistance at the expense of its operation.
