How to Winterize Your Home | Wisconsin Checklist

Why Wisconsin Winterization Is Non-Negotiable

Most states can afford to be casual about winter prep. Wisconsin cannot. Temperatures that drop to -20 degrees, ice storms, heavy snow loads, and months of sustained cold create conditions that punish under-prepared homes. A single frozen pipe can release hundreds of gallons of water. Ice dams can peel off entire sections of roofing. And a furnace that has not been serviced can fail on the coldest night of the year. The good news: a thorough fall checklist addresses all of these risks and saves money in the process.

Heating System: First Priority

Schedule a Furnace Tune-Up

Book this in September before HVAC companies are swamped:

Professional cleaning and inspection: $100-150
Technician will check heat exchanger, burners, blower, and controls
Identifies worn parts before they fail in a cold snap
A maintained furnace is 10-15% more efficient than a neglected one

Replace the Air Filter

Install a fresh filter before heavy heating season begins. A dirty filter makes your furnace work harder, increases energy costs, and can cause overheating. In Wisconsin, change filters every 1-2 months during winter.

Test the Thermostat

Verify it calls for heat and the furnace responds
Consider upgrading to a smart thermostat for automatic setbacks
Program for 68 degrees while home, 60 degrees overnight or when away

Check Carbon Monoxide Detectors

Combustion appliances—furnaces, boilers, fireplaces—produce carbon monoxide. CO poisoning risk increases in winter when homes are sealed tight. Replace batteries and test each unit. Replace detectors over 7 years old.

Service Your Fireplace and Chimney

Have chimney professionally swept and inspected before first use of the season
Check damper operation—close it when not in use to prevent heat loss
Inspect firebox for cracks
Ensure chimney cap is in place to prevent animal entry and water intrusion

Plumbing: Freeze Prevention

Shut Off and Drain Exterior Faucets

This is critical in Wisconsin and must happen before the first hard freeze:

Locate the interior shutoff valve for each exterior faucet (usually near the foundation)
Turn the interior valve off
Open the exterior faucet to drain remaining water
Leave the exterior valve open all winter to allow any residual water to expand without bursting the pipe
Disconnect and store garden hoses—a hose left attached traps water in the pipe

Winterize the Irrigation System

Irrigation lines hold water that will freeze and burst if not removed:

Shut off the irrigation water supply
Manually drain what you can
Have a professional blow out the lines with compressed air—this is worth hiring out
Cost: $75-150 for professional blowout
Timing: Before the first hard freeze, typically mid-October in most of Wisconsin

Insulate Vulnerable Pipes

Pipes in unheated spaces are at risk:

Garage: Water pipes running through attached garages are vulnerable
Crawl spaces: Insulate any pipes exposed to outside air
Exterior walls: Pipes running in poorly insulated exterior walls can freeze
Basement rim joists: The area where the floor framing meets the foundation is often a cold spot
Foam pipe insulation is inexpensive and DIY-friendly—about $1 per linear foot

Know Where Your Main Shutoff Is

If a pipe bursts, the fastest way to limit damage is shutting off the main water supply. Locate and label it now. In an emergency, you will not have time to search.

Roof and Attic: Ice Dam Prevention

Clean Gutters Thoroughly

Clogged gutters trap snowmelt, which refreezes at the eaves and contributes to ice dams. Clean gutters after leaves finish falling—typically late October to early November in Wisconsin.

Confirm downspouts flow freely
Ensure downspouts direct water away from the foundation
Check that gutters are properly sloped toward downspouts

Inspect and Improve Attic Insulation

Ice dams form because heat escaping through the roof melts snow, which refreezes at the cold eaves. The fix is keeping heat inside the living space:

Wisconsin recommended attic insulation: R-49 minimum
Check current depth: 13 inches of blown fiberglass = roughly R-38
Seal air leaks around light fixtures, attic hatches, and penetrations before adding insulation
Proper attic insulation can save 10-50% on heating costs

Check Attic Ventilation

Proper airflow through the attic keeps the roof deck cold and uniform, preventing ice dams:

Soffit vents should be clear of insulation
Ridge vents should be unobstructed
A cold, well-ventilated attic is what you want in winter

Inspect the Roof

Walk around and look for missing or curling shingles, damaged flashing, or areas where ice dams formed last year. Address repairs before winter—a small leak becomes a large one under snow load.

Sealing the Building Envelope

Caulk and Weatherstrip Doors and Windows

Air leaks are one of the biggest sources of heat loss:

Check caulking around window and door frames—replace any that is cracked, missing, or separated
Test weatherstripping by closing a door on a piece of paper—if it slides easily, the seal is inadequate
Replace worn door sweeps
Caulk around utility penetrations through exterior walls (pipes, wires, HVAC lines)

Insulate Electrical Outlets and Switches on Exterior Walls

These are often overlooked air leak sources. Foam outlet gaskets cost pennies and install in seconds behind the cover plate.

Check the Attic Hatch

An unsealed attic access hatch can lose as much heat as a small window left open. Add weatherstripping around the perimeter and insulation to the top of the hatch door.

Exterior and Grounds

Disconnect and Store Garden Hoses

A hose left connected traps water in the exterior faucet pipe. Always disconnect before the first freeze.

Trim Overhanging Branches

Ice storms and heavy snow loads bring down branches. Trees over or near your home should be inspected and trimmed:

Remove dead limbs that could fall on the roof
Trim branches within 6 feet of the roof line
Consider hiring a certified arborist for large trees

Protect Outdoor Equipment

Store patio furniture or cover it with quality tarps
Drain and properly store lawn mower—run it out of gas or add fuel stabilizer
Service your snow blower now, before the first snow
Store propane grills in a garage or shed (never indoors with open flames)

Check the Foundation

Look for new cracks from summer settling or root activity
Seal any cracks with hydraulic cement or polyurethane caulk before freeze-thaw cycles worsen them
Ensure window well drains are clear

Emergency Preparedness

Wisconsin winters bring power outages. Be prepared:

Space heater: Keep one for power outages (use safely—keep away from combustibles, plug directly into wall)
Generator: If you have a generator, test it and have fuel stabilizer in stored gas
Know how to shut off utilities: Water, gas, electric—label everything
Emergency kit: Flashlights, batteries, warm blankets, bottled water, non-perishable food
Sump pump backup: A battery backup sump pump is essential if your basement has been wet

Winterization Task Timeline

September

Schedule furnace tune-up
Book chimney sweep
Test smoke and CO detectors

October

Winterize irrigation system
Caulk and weatherstrip
Inspect roof and attic
Trim dangerous branches

Early November

Clean gutters after leaves fall
Shut off and drain exterior faucets
Insulate pipes
Store outdoor furniture and equipment
Service snow blower

The Cost of Not Winterizing

A few hundred dollars spent on winterization tasks prevents far greater costs:

Burst pipe: $1,000-5,000 in repairs, plus potential water damage
Ice dam damage: $1,000-10,000 for roof and interior repairs
Emergency furnace repair: $500-2,000 (higher after-hours rates)
Frozen irrigation line replacement: $500-2,000

Get Professional Help With Winterization

Some winterization tasks—furnace servicing, chimney sweeping, irrigation blowout, attic insulation—are best left to professionals. HomeHelpersCo connects Wisconsin homeowners with trusted local pros who specialize in getting homes ready for our demanding winters.

Get your home ready for winter. Get free quotes from local professionals today.

How to Winterize Your Home: The Complete Wisconsin Checklist