Indoor air allergens can tax your immune system on a daily basis, and cause winter allergies. In the winter, indoor dust and dander levels can be extremely high. Actions to control indoor dust and dander are very strongly recommended by allergists and Doctors. Air duct systems should be professionally cleaned with commercial grade equipment by trained technicians and filters changed regularly, and carpets vacuumed regularly and deep steam cleaned annually by and IICRC Certified Carpet Cleaning Technician to remove excess dust and dander. Sanitizing of air duct systems is also highly recommended. Read More.