A draughty house is the reason the heater runs all evening and the room still feels cold around your feet. Air leaks are the biggest single waste in most Australian homes, and unlike double glazing or wall insulation, you can fix the worst of them yourself in a weekend for well under $200. The payback is fast: most people knock $150 to $400 a year off their heating and cooling once the gaps are sealed.
Here's how I'd work through a house, roughly in order of what leaks the most air per dollar to fix. You don't need all of it. The first four jobs do most of the work.
On a windy day, run the back of a slightly damp hand around your door and window frames, the ceiling manhole, and the spots where pipes come through walls. Cold streams show up fast. An incense stick or a candle works too, watch the smoke bend where air is moving. Older weatherboard and pre-1980 brick-veneer homes leak the most, while newer builds are tighter but still lose air upward through exhaust fans and downlights. Map the house first, then shop.
The single biggest offender is the gap under the front and back doors. A door bottom seal or brush strip fixes it. The screw-on aluminium and brush seals, $15 to $35 at Bunnings or Mitre 10, outlast the stick-on foam types and cope with a slightly uneven floor. Measure the door width first, most are 820 or 870mm, and cut to length with a hacksaw. If you rent and can't drill, a fabric draught snake at $10 to $25 does the same job with no tools and no holes.
The bottom seal handles the floor gap, but the sides and top of the frame need weatherstripping too. Self-adhesive EPDM rubber or a V-seal runs around the door stop so the door closes against it. Spend the extra on closed-cell EPDM: it lasts ten years or more, where the cheap open-cell foam compresses within a season or two and quietly stops sealing. A standard door takes one five to six metre roll, about $12 to $25. Clean the frame with metho first or the adhesive won't hold through summer.
You don't need to rip out old timber windows to stop them leaking. Foam or brush seals in the frame, and a brush pile strip for sliding aluminium windows, close most of the gap. Double-hung timber sashes are the draughtiest, so a sash brush seal, or even a removable silicone rope on the windows you never open, makes a real difference. Budget $30 to $80 to do a room's worth. Full double glazing is a $600 to $1,200 per window job and a separate conversation for another year.
Warm air rises and leaks straight out through the ceiling access hatch and any unsealed exhaust fans. An insulated manhole cover, or honestly just an offcut of insulation batt sat on top, costs almost nothing and stops a surprising amount of loss. Draught-stopping covers for bathroom and kitchen exhaust fans, $20 to $40 each, close automatically when the fan's off. This is the job most people skip and the one I'd do first after the doors.
An open, unused fireplace is a permanent hole in your roof. A chimney balloon or a fitted damper, $30 to $60, blocks it over winter. Just leave yourself a note, because lighting a fire with the balloon still in is a bad afternoon. Older brick homes often have cast-iron wall vents in rooms that no longer need them. If the room isn't a wet area and isn't running a gas heater, you can seal those. Never block a vent that serves a gas appliance or a bathroom, that's a safety line you don't cross.
In older houses with suspended timber floors, cold air rises through the gaps between the boards and along the skirting line. A bead of paintable gap sealant where the skirting meets the floor, and an acrylic filler between boards, takes an afternoon and no special skill. Under the sink and behind the laundry, a bit of foam or sealant around the water and waste pipe penetrations closes gaps you never notice until you go looking. None of it is glamorous and all of it works.
Once the frame's sealed, heavy curtains with a thermal or blockout lining are the cheapest glazing upgrade going. The trick is coverage: mount the rail wide and high, and let the curtain puddle slightly on the floor so warm air can't slide down the cold glass and pool at your feet. A pelmet, or even tucking the top in against the wall, stops that convection loop. This one change makes a single-glazed room feel a category warmer after dark.
Don't try to seal a house completely airtight. Kitchens, bathrooms and laundries need to vent moisture or you trade draughts for mould and streaming condensation on the glass. Rooms with a flued gas heater need their air supply. The goal is to stop the uncontrolled leaks around doors and windows, not to shut off ventilation. If you notice condensation forming after you've sealed a wet area, you've gone a step too far, so add some extraction back.
If you do nothing else this winter: door bottom seals front and back, EPDM weatherstrip on those two frames, a cover on the ceiling manhole, and lined curtains on the coldest room. That's a Saturday, under $150 at Bunnings, and it's roughly seventy per cent of the benefit. The window seals, the chimney balloon and the skirting gaps are next weekend's job if you've caught the bug. Do the doors and the ceiling first, then sit in the room on the next cold night and you'll feel exactly where the last gaps are.
Hero image: Photo by unknown (CC0) via Openverse
