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How to winterize a house: a complete checklist

By Roof & Router Team. Updated October 11, 2026.

When to winterize

Start in early fall, before heating contractors get busy, and aim to finish before your area’s average first frost. In the northern states that usually means September or October. In much of the South, November or later is fine. The goal is to finish the outdoor jobs while it is still pleasant to work outside.

The checklist at a glance

1. How to winterize your furnace or heat pump

Check the filter. ENERGY STAR recommends inspecting your furnace or heat pump filter once a month and cleaning or replacing it as needed. A clogged filter makes the system work harder and can shorten its life. Write the filter size down so you can buy several at once.

Book a pre-season check-up. ENERGY STAR recommends having the heating system checked by a contractor every fall. For gas and oil systems, that includes the gas or oil connections, burner combustion and heat exchanger. A cracked heat exchanger can leak carbon monoxide, which is one reason this job is not a DIY one.

Test the heat before you need it. Turn the heat on during a cool fall day. Burning dust smell for the first few minutes is normal. A smell that lasts, odd noises or no heat at all means a service call now, not during the first cold night.

Clear around the equipment. Keep the area around the furnace, water heater and any outdoor heat pump unit free of boxes, leaves and snow.

2. Fireplace, chimney and vents

The national fire safety standard NFPA 211 says chimneys, fireplaces and vents should be inspected at least once a year, with cleaning and repairs done as needed. That includes the vents for gas furnaces and water heaters, not just wood-burning fireplaces.

Before the first fire, check that the damper opens and closes. Keep it closed when the fireplace is not in use so warm air does not escape up the chimney, but never close it while embers are still smoldering.

3. How to winterize outdoor faucets and pipes

1. Disconnect and drain garden hoses and store them inside.
2. Shut off outdoor faucets from the indoor valve, then open the outside faucet so remaining water drains and has room to expand.
3. Drain sprinkler lines following the system’s instructions. Many owners hire a pro to blow the lines out with compressed air.
4. Insulate exposed pipes in the garage, crawl space, attic and under sinks on outside walls with foam sleeves.
5. Find your main water shutoff valve and make sure it turns.
6. Test the sump pump if you have one: pour a bucket of water into the pit and check that the pump starts and drains it. Winter thaws and spring snowmelt are when it gets the hardest workout.
7. Check the water heater. A setting of 120°F is enough for most homes, and draining a few gallons from the bottom valve removes some of the sediment that builds up in tank heaters. Follow the manufacturer’s instructions.

See our full guide: how to keep pipes from freezing.

4. Roof, gutters and yard

• Clean the gutters after most leaves have fallen, and make sure downspouts carry water at least 5 feet away from the foundation. Clogged gutters can lead to ice dams and water in the basement.
• Use a ladder safely: a stable ladder on firm, level ground, three points of contact, someone to hold it, and at least 10 feet of clearance from power lines. If the roof is steep or two stories up, hire it out.
• Look at the roof from the ground with binoculars for missing or lifted shingles and damaged flashing around the chimney and vents.
• Trim branches that hang over the roof. Heavy snow and ice can bring them down. Leave anything near power lines to the utility or a licensed tree service.
• Put away or cover outdoor furniture, the grill cover and anything that can blow around.
• Get snow gear ready: a shovel, ice melt (pet-safe if you have pets), and a tuned-up snow blower if you use one.
• Winterize the lawn mower and other gas tools: add fuel stabilizer or run the tank dry, following the owner’s manual.

5. Attic insulation, drafts, windows and doors

Air leaks let cold air in and warm air out. Common culprits are door bottoms, window frames, attic hatches, and gaps where pipes and wires pass through outside walls.

Check the attic first. Heat escaping through a thin or patchy layer of attic insulation warms the roof deck, melts snow, and the water refreezes at the cold eaves as an ice dam. If you can see the tops of the ceiling joists, the insulation is probably too thin for a cold climate. Seal gaps around light fixtures, pipes and the chimney chase before adding insulation.

• Find leaks: on a windy day, hold a lit incense stick near the edges of windows, doors and outlets on outside walls. Where the smoke wavers, air is leaking. Keep it away from curtains, never leave it burning, and do not do this while a fireplace is burning.
• Doors: replace worn weatherstripping and add a door sweep if you can see daylight under the door.
• Windows: caulk gaps in the trim. For drafty single-pane windows, shrink-film window insulation kits are a cheap fix for the winter.
• Attic hatch: add weatherstripping and a piece of rigid foam insulation on top.
• Outlets on outside walls: foam gaskets behind the cover plates cut small drafts.
• Storm windows and doors: if you have them, swap screens for glass panels now.
• Indoor humidity: winter air gets dry. Around 30 to 50% relative humidity is comfortable; much higher can cause condensation and mold on cold windows.

6. Safety alarms

The U.S. Fire Administration recommends:

• A smoke alarm on every level of the home, inside each bedroom and outside each sleeping area
• Testing every alarm once a month
• Replacing 9-volt batteries at least once a year, and the backup battery in hardwired alarms (sealed 10-year alarms do not need battery changes)
• Replacing the whole smoke alarm every 10 years

Winter is when homes are sealed up and furnaces, fireplaces and generators run the most, so it is also the season for carbon monoxide. The Consumer Product Safety Commission recommends CO alarms on every level of the home and outside sleeping areas. Check the replacement date printed on the back of each one.

7. Which way should a ceiling fan spin in winter?

ENERGY STAR recommends running ceiling fans clockwise on low speed in winter. At low speed, the fan gently pushes the warm air that collects near the ceiling back down along the walls without creating a cooling breeze. Most fans have a small direction switch on the motor housing.

8. What temperature to set your thermostat in winter

The U.S. Department of Energy suggests 68°F while you are home and awake, and lower while you sleep or are away. It says turning the thermostat back 7 to 10°F for 8 hours a day can save up to 10% a year on heating and cooling. A programmable or smart thermostat makes this automatic.

One exception: during extreme cold, keep the setting steady day and night to protect pipes, and never set it below 55°F.

9. Get ready for power outages

Winter storms knock out power. Before one hits:

• Emergency kit: flashlights and spare batteries, phone power banks, water, food that needs no cooking, a first-aid kit, and any medications.
• Warmth without power: extra blankets and sleeping bags. Never heat the home with a gas oven, outdoor grill or camp stove. If you use a space heater while the power is on, keep it 3 feet from anything that can burn, plug it directly into a wall outlet, and turn it off when you leave the room or sleep.
• Backup power: a portable power station can keep the fridge, Wi-Fi, phones and lights going. Use our power station size calculator to size one. If you use a generator, the CPSC says to run it outdoors only, at least 20 feet from the house, with the exhaust pointed away. Never run one in a garage, even with the door open.

10. If you have a second home or will be away

Leave the heat on at 55°F or higher, shut off the main water valve and drain the lines if you will be gone a long time, unplug electronics, and ask someone to check the house after hard freezes and big storms.

Quick answers

When should I winterize my house? Before your area’s average first frost. Early fall is ideal because contractors are less busy and outdoor jobs are easier.

What is the most important winterizing job? Protecting your pipes and having the heating system checked. A burst pipe or a failed furnace during a cold snap is the most expensive and dangerous winter problem.

How much does it cost to winterize a house? The DIY jobs, like filters, weatherstripping, caulk, pipe sleeves and door sweeps, typically cost somewhere around $50 to $200 in materials, depending on the size of the house. A furnace tune-up, chimney inspection and sprinkler blowout are paid services; prices vary widely by region, so get quotes.

Can I winterize a house myself? Most of this checklist, yes. Leave gas appliance service, chimney inspection, roof repairs and anything near power lines to licensed pros.