Performed air duct cleaning and sanitation on 5 bedroom house with a single oil furnace. All vents and ductwork are clear of dust and debris at this time. System is functioning properly at this time. Replaced 16x25 filter. Recommend duct cleaning every 3-4 years. Performed a second floor dryer vent cleaning. Dryer vent, duct,flex hose and lint trap are all clear of lint and debris at this time. Dryer is functioning properly at this time and exhaust flow is optimal. Recommend dryer vent cleaning every 1-2 years. Thank you for your business!