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Stopping draughts

One of the simplest steps toward a warm home is to stop draughts and keep the heat inside your home.

Stop those draughts

Draughts are caused by air passing from the outside to the inside, or from the inside to the outside, because of pressure differences caused by wind or warmer indoor temperatures. Rather than ventilation, which you can control, draughts cause heat loss and uncomfortable breezes when you don’t want them.

While most new homes these days are more airtight than older houses, more complicated designs make it easier for warm air to leak out. Addressing draughts in both new and existing homes can make a big difference to your comfort – and your heating bill.

When should you draught stop?

As a rule of thumb, all houses built before the 1960s, and most houses built before the 1980s will need some draught stopping. All ages of homes require maintenance to keep the weather and wind out and the heat in.

Think about stopping draughts in autumn, before the winter cold kicks in.

If you’ve done draught stopping before, it’s also important to make sure weather strips around windows and doors are still clean and working. New draught stopping may need to be done in heavy use areas every three to five years.

Weather stripping around doors and windows

Draughts from under external doors are a major source of heat loss in our houses. Cat doors are another source of draughts if they do not close properly. Check your cat door and fix or replace it if it is a bad fit.

You may also feel draughts from gaps under internal doors. Door sausages at the base of doors and weather stripping doors help to keep warm air in the heated areas of your home.

Draughts from windows are common, but often they are a symptom of a need for window maintenance. Before you draught stop, make sure window catches and hinges are working properly and fix any that are broken or damaged.

If your curtains are moving, that’s a good sign that you have a draught. Alternatively, you can light a candle and use it to find the source. Move the candle around the edge of a frame – the flame will flicker where the draught is coming in. Be careful that you don’t set the curtains on fire!

What to use

There are a variety of weather stripping products – most are available from hardware stores.

It is often difficult to calculate the size of the gap when weather stripping. To help you measure small gaps, a useful gauge can be to test the thickness with the edge of a coin and then measure it.

Self-adhesive foam strip

  • Best for: door frames, so that the door fits snugly when closed. If you use this product on windows, don’t use one that is too thick – otherwise it will be hard (or impossible) to close the window.
  • Don’t use for: wooden windows, as it can warp them over time.
  • Available from: hardware stores, usually in packs of different thickness, or strips you can cut off to the length you want.
  • What to do: look closely at the gap you want to fill and, if possible, measure its width in millimetres before buying your weather strips. Make sure the surface is clean when you stick it on (clean and then wipe with methylated spirits to remove any grease).

Self-adhesive rubber strip

  • Similar to foam in terms of availability and use.
  • It is a more long-lasting product, so although it is slightly more expensive, it is probably worth the cost.

Self-adhesive V seal

  • Best for: windows, although they can be used on doors. Particularly good for older wooden sliding windows, double-hung sash windows (like in a villa) or wooden casement windows (like in a bungalow or houses built in the 40s and 50s).
  • Available from: hardware stores and community energy conservation groups – you can find a member or associate to help you on the Community Energy website.
  • What to do: fold the plastic tape in half (make sure it’s a really good fold) before doing the installation. Clean the frame surface and wipe with methylated spirits to get rid of any grease before you stick it on.

Brush strips

  • Best for: the bottom of external doors, so that it stops draughts coming in the gap under the door.
  • Available from: hardware stores, in a range of colours and styles.
  • What to do: mount it using screws on either side of the door (inside or out) depending on the way the door opens. You may need to cut it to size.

Keyhole covers that fit over the keyhole to prevent draughts when the lock is not in use

  • Best for: locks with holes that go right through the door. Use on either the inside or outside of the door or both
  • Available from: locksmiths.
  • What to do: fit these over the lock so that they pivot at the top and are simply swung out of the way when the lock is used and swung back afterwards.

Draught sausages

  • Best for: the bottom of internal doors.
  • Available from: make them yourself or buy deluxe versions (that go under the door and surround both sides) from homeware or hardware stores or community energy conservation groups – you can find a member or associate to help you on the Community Energy website.

Using curtains and pelmets

Curtains are an effective way of improving your window performance – in summer and in winter – because they keep an air pocket between the curtain and glass. In winter a good, thick, lined curtain will reduce heat loss through your windows, as well as reducing draughts and the feeling of cold radiating into the room.

The air between the curtain and the pane of glass needs to be still for the curtains to be effective. Make sure your curtains close well, and that there are no gaps around the edges. Have curtains that go down to the floor to stop cold air escaping at the bottom. Pelmets can help stop cold air escaping at the top of windows also. Tracks designed to fit close to the wall or window frame also help with this.

Curtains can be a cheap way to improve your window insulation and stop draughts. You can make your own insulated curtains – buy the insulating lining and sew it on the back of existing curtains. Alternatively, try curtain banks for a cheap source of second-hand curtains – make sure they fit your windows down to the floor. A good variety can be found at your local community energy group

Windows and curtains factsheet on the Eco Design Advisor website provides practical and detailed curtain advice.

Further draught prevention

If you are building a new house, prevent future draughts by sealing gaps between window and door frames and the wall framing during construction, and ensuring your floors, walls and ceiling have snug-fitting insulation installed. Consider including an enclosed entryway (ie an airlock) into your design so that all your warm air doesn’t escape when you come in and out the door.

Avoid or replace old style downlights which are not Insulation Contact (IC) and Insulation Contact – Fire Resistant (IC-F) rated. These old style recessed light fittings create a hole in your ceiling and insulation that draws warm air up into your ceiling space.

Downlights and recessed lighting has more information. 

Well-installed insulation with no gaps will also keep out draughts, especially under a timber floor. You may also have gaps between your floor and skirting board. You can use sealant to seal these. Vacuum carefully around the gaps to be sealed and then apply the sealant directly into the gaps.

Open fires are a source of draughts as warm air is drawn up the chimney. If your open fire is not in use, block it off.

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Note that this document is published by the Ministry of Business, Innovation and Employment Chief Executive as Guidance under Section 175 of the Building Act 2004. This is a guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case.