Warm your home for less: Windows and doors

Information sourced from Genless.govt.nz, an EECA initiative.

Windows and doors let light and fresh air into your home, but they can also let heat escape. Here are a few simple ways to keep the cold out and the warmth in.

Draught stopping

Draughts make it difficult and expensive to heat our homes over Winter. Blocking them is usually easy and cost-effective. Here are some common sources of draughts, and ways to deal with them:

  • Place draught stoppers along the bottom of doors to prevent cold air getting in to your home.
  • Tighten latches, hinges and catches on doors to minimise heat loss over Winter.
  • Seal gaps around doors and windows with weather stripping products like self-adhesive foam draught seals, self-adhesive soft rubber, and self-adhesive soft woven pile draught seals
  • Use clear or paintable sealant around door and window trims.
  • Replace damaged rubber seals around aluminium joinery.
  • Seal ill-fitting ceiling hatches with weather stripping products.
  • Block unused fireplaces and chimneys. A good tip is to use a rubbish bag filled with shredded paper.
  • Check extractor fans and rangehoods are not letting in any unwanted draughts.
  • Seal skirting boards and cornices– use flexible silicon-based or latex sealants, or foam the gap where the floor and wall or the ceiling and wall meet.

For more tips on eliminating draughts, go here


A significant amount of heat is lost through your home’s windows. One way to reduce heat loss is to make sure they’re well insulated.

Double glazing

Double glazing can halve heat loss through windows and reduce or eliminate condensation. The process traps an insulating gas layer between two panes of glass where heat is held. It’s standard in new homes, but if your home’s windows aren’t sufficiently insulated, it’s recommended to install double glazing to large windows and the areas of the house you mainly heat.

Here are some are cost-effective alternatives to installing new double glazed glass units into existing frames.

DIY window insulation kits – these work on the same principle as standard double glazing, creating a layer of still air in front of the glass that acts as insulation. For more information on DIY window insulation kits and tips for installing, go here.

Acrylic sheets– these are magnetically attached to the inside of existing window sashes or frames.

Low-E window film–a polyester film with a micro-thin, transparent metal coating which is directly stuck to existing glass. It reflects heat and reduces the amount of energy you need to heat or cool your home. On single glazed windows, low-E window film works best in homes with little condensation on windows.

Check with a professional before installing alternative glazing options.

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Curtains and blinds

Curtains reduce lost heat through windows, and to be effective, they need to be well installed without gaps. This prevents cold air moving between the window and room. Here are a few handy tips to ensure your curtains are keeping in as much heat as possible:

  • Curtains should have a double layer, with thick lining, and be fitted tightly against the wall or window frame.
  • Net curtains installed close to windows can also be effective.
  • They should be wide enough to overlap the window frames at the sides and long enough to touch the floor.
  • If your home has blinds, they should be installed with minimal gaps around them. Honeycomb blinds offer good insulation because they have air pockets within the blinds.

Open curtains and blinds during the day to let the heat in, and close them before sunset to help retain warmth from the sun.

You can help make a difference!

Help to keep thousands of Kiwis experiencing hardship warm this winter by making a donation to Whānau Āwhina Plunket and Variety - the Children's Charity.