How to draught proof your home yourself in NSW

1. Pick a windy day. Draughts are easiest to find when the wind is pushing air through the gaps.
2. Close everything up. Shut the windows and outside doors, and turn off fans and the air conditioner.
3. Do the incense test. Hold a lit incense stick near door and window frames, skirting boards, vents, exhaust fans, the fireplace and anywhere pipes come through a wall. Smoke that blows sideways or is drawn in shows a gap. Keep it away from curtains and never leave it burning.
4. Look and listen. Rattling or whistling in the wind, curtains that move with the windows shut, light showing under a door, and cold spots you can feel are all signs.
5. Write it down. Make a list room by room, so you can buy everything in one trip.

For a full picture, a professional can do an air leakage test (sometimes called a blower door test), which pressurises the house to show where air gets in.

• Outside doors. Fit a door bottom seal to close the gap above the floor, and self adhesive weather strip around the frame where the door shuts. Close the door on a sheet of paper: if it pulls out easily, the seal is not touching. A door snake does the job for free if you have an old towel.
• Internal doors. Seal the doors to rooms you do not heat or cool, such as the laundry and spare rooms, so you only heat the part of the house you use.
• Opening windows. Put foam or rubber strip on the frame where the window closes. For sliding windows, use brush strip, which lets the sash slide. Old timber sash windows are fiddly, so get a carpenter or window specialist if they rattle.
• Fixed windows and frames. Run gap filler along any gap between the window frame or architrave (the timber trim) and the wall.
• Skirting boards and floorboards. Fill gaps between the skirting and the floor or wall with a flexible, paintable gap filler. Small gaps between floorboards can be filled the same way. Big gaps across a whole floor are better sealed from underneath, which is a job for a builder or insulation installer.
• Exhaust fans. A ceiling fan that vents into the roof lets warm air out all day. Fit a draught stopper over it, or have an electrician swap the fan for one with built in back draught shutters. Check the stopper suits your fan first: some do not fit centrifugal fans or 3 in 1 heat, light and fan units.
• Unused chimneys and fireplaces. An open chimney is a big hole in the roof. If you never use the fireplace, block the flue with a chimney draught stopper made for the purpose, and take it out before you ever light a fire. If a gas heater or gas log fire uses the chimney, do not block it.
• Wall vents. Older homes often have vents high on internal walls. The Australian Government says you can seal ones you do not need, unless you use an unflued gas heater, which needs them. See the safety section below first.
• Evaporative cooler vents. Cover the ceiling outlets in winter, when the cooler is off and the heating is on.
• Pet doors. Choose a pet door with a brush or magnetic seal around the flap. If the flap no longer closes flush, a replacement flap is cheaper than a new door.
• Pipes and cables through walls. Seal small gaps around pipes under sinks and around air conditioning pipes with gap filler.

Rough prices for DIY materials at Australian hardware stores in October 2026, including GST:

Measure the gaps before you buy. Weather strip and door seals are made for a range of gap sizes, and one that is too thick stops a door or window closing. A caulking gun, a hacksaw and a tape measure cover most jobs.

Sealing too much can be dangerous. Gas appliances need fresh air to burn safely, and homes need ventilation.

• Unflued gas heaters. They release their fumes straight into the room, including carbon monoxide. NSW Health says to check the room has air vents and that they are not blocked, to keep a door or window open if there are none, and never to use one overnight in a room where you sleep.
• Gas hot water and flued heaters. NSW Fair Trading warns that if the ventilation to a gas water heater is blocked, carbon monoxide can be forced back into the room. You cannot see or smell it. Never seal or cover a flue, or the vents near any gas appliance.
• Exhaust fans with a gas heater. In a well sealed home, a strong exhaust fan or range hood can pull fumes back down a heater's flue. If you have a gas heater, have a licensed gasfitter check it after you draught proof.
• Subfloor vents. The vents low in outside brick walls let air flow under the floor and keep it dry. Leave them open.
• Downlights. Fire and Rescue NSW warns that halogen downlights run hot and that insulation or other material touching them can smoulder or catch fire. Do not cover, stuff or seal over them.

Condensation and mould. Draughts carry damp air out. Once they are sealed, run the bathroom fan when you shower, use a range hood that vents outside when you cook, and air the house each day. If you see condensation on windows or mould on ceilings, you need more ventilation, not less sealing.

• Electrician: replacing old downlights with sealed LED fittings rated to be covered by insulation, and swapping or wiring exhaust fans.
• Licensed gasfitter: any work near a gas heater, gas log fire or gas hot water, and a safety check of gas appliances once the house is sealed.
• Carpenter or window specialist: old sash windows, warped doors that no seal will close, and large gaps in walls.
• Builder or insulation installer: sealing floors from underneath, and work in the roof space.
• Energy assessor: an air leakage test, if you want to measure how leaky the house is before and after.

Draught proofing is on the approved list for the NSW Home Energy Saver loan, though the lenders did not yet offer it when we last checked. See our guide to the loan.

How do I find draughts in my house?

Wait for a windy day, close all the windows and outside doors, and turn off any fans. Then hold a lit incense stick near door frames, window frames, skirting boards, vents and exhaust fans, and watch the smoke. Where it blows sideways or gets sucked in, there is a gap. Rattling or whistling in the wind, curtains that move when the windows are shut, and a breeze you can feel are signs too. For a full picture, a professional can do an air leakage test.

How much does draught proofing cost?

Doing it yourself is cheap. A door snake costs about $6 to $10, a 5 m roll of self adhesive weather strip about $7 to $11, a door bottom seal about $17 to $43, a tube of gap filler about $15 to $17, and an exhaust fan draught stopper about $40 to $45. Most homes can do the main doors, windows and gaps for a few hundred dollars in materials.

How much can draught proofing save?

The Australian Government says sealing gaps may reduce heat loss by 15% to 25%, based on CSIRO research from 2015. How much that cuts your bill depends on how leaky your home is now and how much you heat and cool it.

Which vents should I never block?

Never block the vents in a room with an unflued gas heater, or the vents and flue of any gas heater or gas hot water system. Leave the vents under the floor in your outside brick walls open, as they keep the space under the house dry. Keep kitchen and bathroom exhaust fans working, and only fit draught stoppers that open when the fan runs. If you are not sure what a vent is for, leave it alone and ask a licensed gasfitter or builder.

Can draught proofing cause condensation or mould?

It can if the home has no other way to get rid of moisture. Draughts carry damp air out, so once they are sealed you need to do it on purpose: run exhaust fans when you shower and cook, use a range hood that vents outside, and open windows for a while each day. The Australian Government says draught proofing should go hand in hand with good ventilation.

Should I seal around downlights?

Not yourself. Older open downlights let warm air escape into the roof, but halogen downlights run very hot and Fire and Rescue NSW warns that insulation or other material against them can smoulder or catch fire. The safe fix is to have a licensed electrician replace them with sealed LED downlights rated to be covered by insulation.

Do I need a tradie to draught proof my home?

Not for most of it. Door seals, weather strip, gap filler, door snakes and exhaust fan draught stoppers are all DIY jobs. Call a tradie for anything electrical (downlights and wired exhaust fans), anything to do with gas heaters, flues or chimneys used by a gas appliance, old sash windows, large gaps in walls or floors, and an air leakage test.

Can I draught proof a rental?

Door snakes and removable products are fine. For anything fixed, such as screwed on door seals or gap filler, ask your landlord or agent first. If the home has a gas heater or gas hot water inside, tell them before you seal anything near it.

Draught proofing works best alongside insulation. Type your address to see the upgrades that suit your home, what they cost and the rebates you can get.