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By Kate Cranney 28 April 2020 6 min read

Updated 13 May 2021

Just when you thought working from home would save you time and money, the first winter bill arrives! COVID-19 restrictions are necessary, but they may leave us out in the cold! Now you're spending more time at home you might be noticing your house is draughty.

Isn’t winter romantic? Crisp mornings, hearty stews and hot chocolate. Mmm… But huddling around the heater shivering with your housemates – not so romantic! With winter on our doorstep, the last thing we want are our dollars leaking out through the cracks in our homes.

So draughty!

Talk to most renters, and you’ll hear some winter woes. Wearing coats indoors, gaps in floorboards, and draughts coming from…somewhere! We had a chat with Michael Ambrose, our Senior Experimental Scientist and former architect, about why some Australian homes are so cold.

“Some houses in Australia are designed to be leaky. In northern Australia, ‘troppo architecture’ houses are designed to be open to breezes, to keep the house cooler in summer,” Michael said. But unintentional draughts are an issue in southern Australia where they can add up to 20 per cent to your energy bill.

Home truths

“Leaky houses tend to go with age. The older the home, the leakier it is. Old weather board houses from the 1950s are very leaky, especially if they're on stumps. You don’t get leakage through concrete slabs,” he said.

Michael, along with Mike Syme, former Senior Research Engineer, collaborated on one of the only studies on how airtight Australian homes are. The study found that Australian homes are ‘leaky’ by international standards and older buildings are generally much draughtier.

During the recent bushfires, Australians were encouraged to close their doors and windows to minimise exposure to fine smoke particles. But in many homes, this smoke simply seeped in through the cracks and gaps.

In Australia, there is currently no specific level of air tightness for new homes to achieve. The building code states “sealing of the building envelope against air leakage” is required for compliance. But there is no measure as to what is an appropriate level of sealing.

Testing, testing

Michael and Mike tested homes using a ‘blower door test’. The equipment sucks air into the house, before reversing it and blowing the air out. It calculates how many air changes per hour are occurring. Blower door tests find where there are gaps, where draughts form, where cold air can seep in and warm air can seep out. These gaps need to be sealed up.

Tips to draught proof your house

Michael has some tips and tricks to make your home-office a little warmer this winter. These hacks can help you save your hard-earned cash.

1. Windows

Uncovered windows account for up to 40 per cent of heat loss in the winter. 

  • Use heavy, lined curtains that fall below the window to keep warmth in
  • Check your windows for cracks
  • Consider sealing gaps with insulation strips or caulk (a waterproof filler)
  • Install pelmets above your windows/curtains to stop warm air escaping
  • You can also hang a heavy blanket or towel off the curtain rod.
  • Replace windows with double-glazing, use window films, or install insulating window coverings. 

2. Doors

Sealing gaps around doors can help draught proof your house.

  • If you feel a draught, make a ‘door snake’ for internal doors
  • For external doors, use a plastic or metal door seal with wipers
  • For draughts around the edges of the door, use adhesive weather stripping.

3. Old heaters, fireplaces and hot water systems

Sometimes when services are removed the hole isn’t sealed. To draught proof the house you'll need to seal it up.

  • Look for gaps around built-in appliances, at the back of cupboards and under the kitchen sink 
  • You can fill gaps with expanding foam 
  • If you have an old fireplace, use fireplace dampers to block airflow. 

4. Fixed vents and exhaust fans

  • Some old brick homes have fixed ceiling and wall vents. Block these to stop air leakage
  • For old exhaust fans, use a ventilation cover to block the vents over winter.

5. Evaporative cooling units

These are meant to have winter covers or dampers but they’re not always effective.

  • You can draught-proof them by using magnetic strips around the vent receiver in your ceiling
  • Clip the covers on in winter and peel them off in summer.

6. Other gaps

  • Listen for rattles or whistling and feel for moving air
  • Kitchen cabinets are often leaky, there may be gaps around the pipes and joints in the cabinets
  • Other areas include where skirting meets the wall, and where bricks meet the wood trim
  • Fill small gaps with silicone sealant
  • Fill bigger gaps with expanding spray foam
  • Be careful around internal gas appliances as they need fixed ventilation.
  • Replace vented downlights with Insulated Cover (IC) rated LED downlightsThese can be covered with ceiling insulation so they don’t leave an uninsulated gap. 

7. Rugs and carpets

Cold air can roar up through gaps in the floorboards, especially in timber homes raised above the ground.

  • Use rugs and carpets to act as a layer of insulation.

8. Let the sunshine in

  • Keep your blinds or curtains open during the day to warm your home, especially north and west-facing rooms.

9. Insulate ceilings, underfloor and walls (in that order)

Ceiling insulation is generally the easiest to install and has the best bang for your buck. In cool climates, you should aim for R4.0 rating in ceilings. Make sure your insulation doesn’t touch the roof sheets at the edges of the house and be careful to leave space around downlights. 

Underfloor insulation is a hit harder and dirtier to install, particularly if your house is close to the ground. But it will help prevent cold air from the subfloor being pulled into the room by convection when you turn on the heater. This is especially the case if have polished floorboards, which have a tendency for air gaps. 

Wall insulation can be retrofitted using several products. But it can be expensive, difficult to do comprehensively, and can cause moisture problems if not done properly. Speak to your contractor about water ingress and get guarantees.

10. Replace appliances

For better winter performance, consider replacing central heating with separate split systems. They’re cheaper to run, and you can decide which areas of the house to heat and cool. See our renovate or retrofit tips here. 

Let the sunshine in to warm your home. For more ideas, look to our tips on giving power bills the cold shoulder. Or on the government’s heating and cooling site. Some states offer rebates for professionally installed draught-proofing. And if you’re a concession card holder you may get free materials. Visit the Australian Government's Your Energy Savings website.

We hope you can keep a little warmer at home this winter.

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