How to Winterize Your Home: A Step-by-Step Cold-Weather Checklist

Preparing a home for winter covers four areas: sealing the building envelope, protecting plumbing, servicing heating equipment, and guarding against carbon monoxide and fire hazards. The recommendations below come from the US Department of Energy, the National Weather Service (NWS) and the US Consumer Product Safety Commission (CPSC).

Seal drafts and upgrade insulation

The Department of Energy notes that a typical home loses more than 25% of its heat through windows. Its Home Energy Checklist recommends applying rope caulk or film to leaky windows, and upgrading with weatherstripping or storm windows and doors to stop cold air from entering and warm air from escaping.

The agency also advises bringing attic insulation levels up where needed and insulating heating ducts that run through unheated spaces such as basements or crawl spaces, saying this step can save up to 60% of the heat otherwise lost at the registers before it reaches living areas.

Protect pipes from freezing

The National Weather Service advises letting taps drip during very cold temperatures to keep water moving through pipes, and opening cabinet doors under sinks so household heat can reach plumbing that runs along exterior walls. The Department of Energy separately recommends insulating hot water pipes to reduce heat loss year-round.

If pipes do freeze, the National Weather Service says to thaw them slowly with an electric hair dryer and warns against using a blowtorch or other open flame near plumbing.

Service heating equipment and set temperatures

The Department of Energy recommends having a furnace or heat pump receive professional maintenance every year and cleaning or replacing filters regularly. It also suggests installing a programmable thermostat that sets back the temperature automatically at night, turning the water heater down to a warm setting of 120°F, and opening curtains on south-facing windows during the day to let sunlight add passive heat.

Guard against carbon monoxide and fire risks

Heating equipment runs more in winter, raising the risk of carbon monoxide exposure. The CPSC recommends installing battery-operated CO alarms, or alarms with battery backup, on every level of the home and outside sleeping areas, with interconnected units preferred so that one alarm triggers all of them. Warning signs of CO poisoning include headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion; the agency says anyone experiencing these symptoms should move to fresh air immediately and call 911.

Portable generators are a major source of risk: the CPSC states that one unit produces as much carbon monoxide as hundreds of cars and links more than 100 US deaths a year to generator CO exposure. Generators should run outdoors only, at least 20 feet from the home with exhaust directed away from windows and doors — never in a garage, even with the door open. The National Weather Service separately advises giving space heaters an automatic shut-off switch, keeping them away from flammable materials and extension cords, using battery-powered flashlights instead of candles during outages, and making sure fireplaces and wood stoves are properly vented.

Winterization checklist, in order

1. Seal visible air leaks around windows and doors with caulk, film or weatherstripping.
2. Check attic insulation levels and top up where heat loss is apparent.
3. Insulate exposed hot water pipes and ductwork running through unheated spaces.
4. Schedule professional maintenance for the furnace or heat pump and replace filters.
5. Install a programmable thermostat and set the water heater to 120°F.
6. Locate the main water shutoff and insulate pipes along exterior walls.
7. During very cold snaps, let faucets drip and open cabinet doors under sinks.
8. Install or test battery-operated carbon monoxide alarms on every level of the home.
9. Keep any portable generator at least 20 feet from the house, running outdoors only.
10. Stock flashlights, batteries and warm bedding in case of a power outage.