Outside
Do these before the first hard freeze:
- Clean gutters and downspouts, and check that water drains away from the foundation
- Disconnect and drain garden hoses; shut off outdoor spigots from inside
- Walk the roof line for missing shingles or lifted flashing
- Seal gaps around windows and doors with fresh caulk
- Trim branches that touch the roof or overhang power lines
Inside
- Replace the furnace filter and book a heating tune-up
- Test smoke and carbon-monoxide alarms; replace batteries
- Reverse ceiling fans to push warm air down
- Check weatherstripping on exterior doors
- Bleed radiators if you have hot-water heat
If you only do three
Gutters, spigots and the smoke alarms. They cost the least and prevent the most.