1. Sealed to the outside to prevent currents of cool air
   "They installed draftproof windows to keep the house warm in winter";
   - draughtproof [Brit]

1. Seal to keep stop cool air flowing in
   "We need to draftproof the doors before the cold weather sets in";
   - draughtproof [Brit]

Derived forms: draftproofed, draftproofing, draftproofs