How to Prepare Your House for Winter: A Complete Checklist

Your first winter in a new home reveals everything the previous owners didn't tell you. Drafty windows, pipes in unheated spaces, a furnace that's never been serviced, an irrigation system that hasn't been blown out in years. New homeowners who didn't grow up maintaining a house often don't know what they're supposed to do before cold weather arrives — and they find out the expensive way.

This is the complete pre-winter checklist, organized by task priority.

First: Find Your Main Water Shutoff Valve

Before anything else — especially before the first cold snap — know where to turn off your water in an emergency.

The main water shutoff is typically located:

• In the basement, on the wall facing the street (where the municipal supply line enters the house)
• In a crawlspace, near the foundation wall
• In a utility room or mechanical room, near the water heater or furnace
• Outside near the foundation, in a small ground-level box (common in warmer climates)

Turn it yourself once to confirm it works and to note what type of valve it is. A gate valve requires several full turns clockwise to close. A ball valve closes with a 90-degree turn to perpendicular with the pipe. If the valve is old, stiff, or corroded, add valve replacement to your maintenance list — a valve that won't close in an emergency is useless.

Knowing the shutoff location takes 5 minutes and could save you $10,000 in water damage if a pipe bursts.

HVAC and Heating System Service

Schedule a furnace or heat pump tune-up before the first cold day. A professional service ($80 to $200) is not optional — it's a safety step. Gas furnaces need annual combustion testing and heat exchanger inspection for micro-cracks that can leak carbon monoxide into the living space. Heat pumps need defrost cycle verification and refrigerant checks before sub-freezing weather arrives.

Book in September or early October. By November, every HVAC company is booked solid and emergency service premiums apply.

Replace the HVAC filter if you haven't in the last 60 to 90 days. A dirty filter entering peak heating season means the system strains harder through the coldest months.

Test the thermostat. Switch to heat mode and set it above the current room temperature. The system should respond within a few minutes. If it doesn't, check the filter, the circuit breaker, and the emergency shutoff switch (a wall switch near the furnace that looks like a light switch — sometimes accidentally flipped off).

Reverse ceiling fan direction. Flip the directional switch on all ceiling fans to clockwise rotation at low speed. This pulls cool air up from the floor and pushes warm air that's collected at the ceiling back down into the living space, reducing heating load.

Checking for Air Leaks

Air leaks are one of the largest sources of heating energy loss. A house with significant air infiltration can lose 20 to 30% of its heating energy through gaps that cost almost nothing to seal.

How to find air leaks:

Visual inspection: Start with the most common leak points — around door and window frames, at the base of exterior walls, around pipe penetrations through exterior walls (under sinks, behind toilets, around dryer vents), at electrical outlets and switches on exterior walls, and around the attic hatch.

The hand test: On a cold, windy day, slowly move your hand around window frames, door frames, and electrical outlets on exterior walls. You'll feel cold air movement at actual leaks.

The incense stick or smoke pencil test: A slowly burning incense stick or smoke pencil held near suspected leak points will show air movement visually. The smoke drifts toward or away from gaps as air moves through them.

Thermal camera (optional): Inexpensive smartphone-attached thermal cameras ($150 to $250) make air leaks and insulation gaps very visible as cold spots on exterior walls. Worth the investment for a large house or significant energy bills.

How to seal what you find:

• Door weatherstripping: Foam, rubber, or vinyl compression strips apply to the door frame. If you can see daylight around a closed door, it needs new weatherstripping.
• Window caulk: Apply exterior-grade silicone or polyurethane caulk around window frames where they meet the exterior cladding. Let it cure fully before a hard rain.
• Foam sealant: Great Stuff or equivalent expanding foam seals large gaps around pipe penetrations in walls, basement rim joists, and around the dryer vent exit.
• Outlet gaskets: Foam outlet and switch gaskets ($5 for a pack of 25) install behind the cover plate and reduce cold air infiltration through exterior wall outlets significantly.

Outdoor Water System Winterization

Disconnect all garden hoses from exterior spigots. This is the single most important task. A hose left attached traps water inside frost-free faucets and causes internal pipe freezing and bursting. Takes 5 minutes.

Shut off and drain standard (non-frost-free) outdoor spigots. If your exterior faucets are standard (not frost-free), locate the indoor shutoff valve for each and turn it off. Then open the exterior spigot to drain any remaining water.

Blow out the irrigation system (freezing climates). Sprinkler lines left full of water will freeze and crack PVC pipes, shatter sprinkler heads, and damage valves — repairs that run $150 to $350 per section. Professional blowout ($85 to $235) uses a high-volume air compressor (80 to 100 CFM) to purge every zone. This is worth hiring out: under-powered DIY compressors (tank compressors, not pancake compressors) can't fully evacuate water from long runs and give a false sense of security.

Have the irrigation system blown out before the first hard freeze in your area. Check historical first-freeze dates for your location and book the service two to three weeks in advance.

Exterior Inspection

Gutters: Clean all debris after the last leaves fall. Blocked gutters in cold climates cause ice dams. See /blog/how-often-to-clean-gutters.

Roof visual check: Inspect from the ground with binoculars. Look for missing, curled, or damaged shingles that could allow water intrusion under snow load. Loose flashing around chimneys and vent pipes is a common source of winter leaks.

Foundation perimeter: Walk the foundation looking for new cracks or gaps where cold air can enter a basement or crawlspace. Seal with hydraulic cement or expanding foam.

Crawlspace vents: Some older homes have crawlspace vents that should be closed in winter to prevent pipes from freezing. Consult your home inspector's report or a local contractor for guidance — ventilation requirements depend on whether the crawlspace has ground vapor barrier and insulation configuration.

Cut back trees and shrubs: Remove branches within 1 to 2 feet of the siding or roof. Ice-laden branches can fall on the house or damage siding as they move in wind.

Chimney and Fireplace

For wood-burning fireplaces: hire a certified chimney sweep annually. Creosote builds up from wood combustion and is highly flammable — it's a primary cause of chimney fires. Annual sweeping removes creosote before you begin the heating season. Cost: $150 to $300 in the US; £60 to £120 in the UK.

Before the first fire of the season, check the damper. Open it fully and look up — you should see light from the sky. The damper must be open before lighting a fire to prevent carbon monoxide buildup in the house.

Emergency Preparedness

Before winter arrives:

• Stock emergency heating: Know your backup if the furnace fails (space heater, extra blankets, alternate location to stay). A furnace that fails on the coldest night of the year can leave the house dangerously cold in hours.
• Know your propane or oil level if you heat with these fuels. Schedule a delivery or fill before the winter rush.
• Test the generator if you have one — and stock fuel. Many sump pumps, furnace control boards, and well pumps need electricity.

The First-Year Homeowner Maintenance Calendar turns this checklist into a sequential October and November schedule with specific task windows. It removes the guesswork about timing and sequencing — so nothing critical falls through the cracks in your first winter as a homeowner.