Draughts in Australian houses can add up to 20 per cent to our energy bills. Our scientists are here to help! In this series, we share energy efficiency tips for older houses, apartments and new homes.
Winter is a great time to make your home more energy efficient.

Winter is here and temperatures are plummeting around Australia. In this winter chill series, we’ll share energy efficiency tips for older houses, apartments and new homes.

Australian houses are leaky

Australian homes are notoriously ‘leaky’ by international standards. This means warm air is leaking out, and cold air is coming in. These unintentional draughts make our houses cold to live in. They can also add up to 20 per cent to our energy bills.

We all want our homes to be comfortable, healthy, sustainable and inexpensive to heat. So, how do we get there?

We asked Michael Ambrose, former architect and our Senior Experimental Scientist, for his advice on how you can keep the warmth in and the power bills down.

In this three-part series, Michael shares his energy efficiency tips for older houses, apartments and new houses. So, let’s start with older houses.

Older homes and energy efficiency

When we say ‘older houses’, we mean those built before 2001. These homes were typically not subject to any energy efficiency regulations. This means they can be far less energy efficient.

Data from our Australian Housing Data Portal shows the average existing house is rated 2.2 stars for energy efficiency (the most energy efficient houses are 10 stars). This means they’re likely to be very cold to live in during winter.

Older homes are likely to get very cold in winter, especially in chilly Tasmania. Photo by Matt Palmer (Unsplash).

Making your older house more energy effiicient

Michael says there are lots of easy ways you can improve how warm you home is.

“The best thing you can do is to seal draughts (uncontrolled air movement in a building). Most of the problems in homes occur because they’re leaky,” Michael says.

“The hot air can escape from the house, and the cold air can get in. On a windy day, in older homes, you can even hear the doors rattling and feel the breeze inside.”

Michael collaborated on one of the only studies on the airtightness or ‘leakiness’ of Australian homes. The study found Australian homes are ‘leaky’ by international standards and older buildings are generally much draughtier.

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

Top tips for older houses

But there are some simple solutions that can keep you warm and save you money. Here’s Michael’s checklist.

Cover your 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

Seal gaps around your doors

  • 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

Old heaters, fireplaces and hot water systems

  • Sometimes when services are removed the hole isn’t sealed. Seal these up.
  • Look for gaps around built-in appliances, behind 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

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

Evaporative cooling units

  • These should have winter covers or dampers, but they’re not always effective
  • 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

Sealing other gaps

  • Listen for rattles or whistling, and feel for moving air
  • Look for gaps around the pipes and joints in cabinets, especially kitchen
  • 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 rated LED downlights. These can be covered with ceiling insulation, so they don’t leave an uninsulated gap
  • Other areas include where skirting meets the wall, and where bricks meet the wood trim

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

Let the sunshine in

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

Renovate or retrofitting to increase energy efficiency

If you’re looking to do a more involved renovation – including insulation – we’ve got some tips for renovating or retrofitting to keep in mind to save money and energy.

We hope these suggestions keep you a little cosier this winter! And if you want to know more, here are some other resources to help you out:


  1. The suggestions are useful but would be more useful if CSIRO’s experts could give approximate estimates of the cost of each suggestion and of the economic benefit from each one. For example, a door snake might cost a dollar or two but give you how many dollars in energy savings, compared to double glazing costing many 1000s of dollars for what sort of return?

  2. Rented homes are often woefully leaky but renters are not responsible for installing permanent solutions and not necessarily permitted to do so. Expense can also be difficult.

  3. Good to compare all these tips with the advice to stay in ventilated spaces to minimise flu andCovid19 transmission. We need to consider both for a healthy home

  4. The vents in your walls (inside in the plasterboard) are generally safe to seal provided you don’t have an un-flued gas heater. Combustion gases from unflued gas heaters are dangerous and require constant air flow to prevent them building up indoors. This shouldn’t be a problem if you have a modern heater.

  5. Thank you for this great guide!
    Can someone tell me – do we need those wall vents or is it safe to plug them? Are they necessary for ventilation, air quality or something?

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