A door-seal defect can allow air leakage, but a change in the electricity bill alone does not prove it. Inspect the seal first; compare energy impact using measurements under similar operating conditions.
Field inspection
Photograph tears, crushing, hardening and gaps at joints. With the door closed, place a paper strip at several points and pull; mark locations where it slips out easily. This is a screening check, not a technical airtightness test. Have hinges, alignment and the mating surface inspected too.
Make a fair energy comparison
Record meter consumption over equal periods before and after repair. Note outdoor conditions, room setpoint, operating hours, door openings and stock or load changes. An unadjusted monthly bill difference does not show that a saving came from the seal.
Repeat the same physical check after maintenance and record the repair date. If the result does not improve, request a specialist check of the frame, door alignment or operating conditions.
