Anyone that thinks they get 100% of the water out by blowing air through the system is kidding themselves. water will not move once the air can get through. try this. blow air through a garden hose till no more comes out. now pick up one end and watch all the water come out the other side. Not worth it for the small amount of $$ RV antifreeze costs especially where it gets well below freezing for weeks or months.. for those that use it year round or down south where it barely touches freezing or at 30 deg. for a few says you could just pull the low point drains and run a heater with the cabinet doors open.