How to keep heat in

Retaining the heat inside your home will keep you warm and comfortable and help to reduce your heating costs.

Three of the most important factors to retain heat are:

  1. The level of insulation in your home
  2. Sealing out draughts in doors, windows and chimneys
  3. Window design, orientation and coverings
Heat loss without insulation

Step 1: Insulation

Insulation helps to reduce heat loss from your home and is the most effective way to improve the comfort and energy efficiency of your home.

A fully insulated home means you’ll spend less on heating in winter and cooling in summer.

Uninsulated ceilings, walls and even floors can account for significant heat losses, as shown in the illustration below. Check the state of your ceiling insulation, most homes in Victoria have some ceiling insulation but it may not be doing its job and you may need to top up. You can learn more about insulating the home on our insulation page.

Step 2: Sealing out Draughts

Draughts and unwanted air leaks not only make your home uncomfortable, but they can also increase heating costs by around 20%. Minimise heat loss by sealing draughts. You can check for draughts by:

  • Looking for obvious gaps and listening for rattles or whistling around doors and windows
  • Feeling for moving air around doors, windows, fireplaces, air outlets, vents, stairways, floorboards, exposed raftersand beams, built-in heaters and air conditioners, architraves and skirting boards
  • Looking for movement in curtains

Common sources of draughts are:

  • Around skirting boards and architraves 
  • Evaporative cooler outlets 
  • Exhaust fans and vents 
  • Around external doors 
  • Sealing around wall vents

Find out more ways to draught proof your home.

Step 3: Cover your windows

Windows play a big role in retaining heat in your home. A single pane of glass can lose almost 10 times as much heat as the same area of insulated wall.

Heat loss from windows

Reduce heat loss through windows and save money on your winter heating bills. Appropriate window protection creates an insulating layer of still air on the inside of the glass. This can be achieved by the addition of thick curtains and a pelmet.

The diagram below shows the difference between a poorly-fitted and a well-fitted curtain and the effect this has on heat loss. The poorly-fitted curtain allows heat loss to occur, while the well fitted curtain combined with a pelmet significantly reduces heat loss.

Window coverings and heat loss


  • Use closely woven, close-fitting curtains or blinds 
  • Ensure there’s a snug fit on both sides of the window and at the top of the curtain to stop warm air from moving down behind the curtain and cooling 
  • Install boxed pelmets or solid barriers above the curtain rail, or position the curtain within the window space 
  • Use curtain tracks that provide a return of curtain to the wall to create a seal
  • Close curtains or blinds when you have the heating on, especially at night – by leaving curtains or blinds open, you're wasting money and energy

More information