Heh heh! I stuffed towels under my doors.
Do you have natural gas? If so, make sure you have a CO detector, even if your unit is in good repair! Also, fireplaces can put off CO. When you start sealing drafts, you also seal in bad stuff!
Old towels for my place, too. But those stuffed dachshunds and such are definitely cuter...
SirKit found a detector that monitors both CO and Natural Gas leaks. He put it downstairs by the new furnace. We'd gotten CO monitors as soon as they were available, after Vitas Guerulaitis, a tennis star, died of carbon monoxide poisoning.