Follow this handy list (and check it twice) to make sure your home is secured against the winter elements.
Heating system: The colder it gets, the more it costs to fix, so check your heater well before winter. Follow seasonal maintenance in the owner's manual. Change the air filter.
Cooling system: Hose down fan blades and condenser coils on the outside unit. Cover the unit with a securely wrapped tarp to prevent debris and rust. Remove and store window units.
Chimney/Fireplace: Clear the chimney of debris. Ensure flue damper opens properly. Have a professional clean chimneys and stovepipes. Have a professional repair cracks in brick or mortar immediately.
Piping: Insulate all exposed piping and exterior hose bibs and faucets.
Windows: Place a lit candle or burning incense stick nearby to check for drafts and leaks on a windy day. Use rope caulk to seal.
Doors: Check all weather stripping and reinstall new if it appears worn.
Roof: Replace missing or damaged shingles. Check flashing around chimneys and other roof projections. Clean gutters and downspouts.
Sprinkler system: Purge all lines of water with an air compressor to prevent freezing and bursting.
Source: My Home Ideas