Put me down as a "bass ackwards contrarian" also. I can't tolerate CPAP heated humidity. Yet my nasal passages don't swell, probably because I use prescrition Nasonex. However, the least bit of heated humidity causes my lungs to feel extremely stifled----as if I were breathing warm, swampy air. Perhaps my bronchial passages are swelling the same way Derek's nasal passages swell.
I agree with LDuyer that heat can cause fluid retention and capillary-based swelling. Wonder what the temperature difference is between ambient air, non-humidified CPAP air, and air treated with CPAP heated humidification? I've never bothered to measure it...