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Draught stopping

It is hard to keep a draughty house warm and comfortable but the problems are usually fairly cheap and easy to fix.

Even well insulated homes can be hard to heat if draughts constantly replace hot air with cold air. Good building airtightness and controllable ventilation lets you manage air replacement for a warmer, healthier, more comfortable home.

Blocking up draughts is usually cheap and relatively simple to do. There are simple tricks for finding draughts - on a cold, windy day look for curtain movement or use a damp hand or a candle to trace the source of your draughts.

Common sources of draughts and simple solutions

Doors and windows

  • Check hinges and catches or latches. If they are loose, tighten them up.
  • If they don't fit in their frames snugly, find out how to repair them. Get tips on window and door repairs from the ConsumerBuild website.
  • Weather stripping can be used to seal gaps around many doors or windows. Check your hardware store for the right types to use.
  • If you get draughts from around door or window trims, seal behind them with clear or paintable sealant.
  • For gaps under doors, you can fit draught excluders, either brush strip types or for external doors, spring loaded automatic seals.
  • Damaged rubber seals around aluminium joinery can easily be replaced.

Chimneys and fireplaces

  • Gaps around the chimney where it goes through the ceiling. Close the gap using a non-combustible sealant.
  • Unused fireplaces. Block the chimney - a rubbish bag filled with shredded newspapers works well or you can buy inflatable bags to do the same job. Make sure it's very obvious so no one tries to light the fire with a blocked chimney.

Ceilings and floors

  • Ceiling hatch. Make sure it's correctly fitted and use weather stripping to seal it.
  • Gaps between floorboards. Use a flexible, clear silicon-based or latex sealant to fill the gaps. For holes, cover from underneath with a small square of timber and glue a bung of matching wood into the hole. Cut out the bung with a hole saw making it slightly bigger than the hole for a good friction fit. Fill the central pilot hole with wood filler and sand smooth.
  • Unsealed skirting boards and cornices. Use flexible silicon-based or latex sealants to seal the top and bottom of skirting boards and cornices, or remove them and foam the gap where the floor and wall or the ceiling and wall meet.

Appliances and lighting

  • Gaps around electrical wiring and plumbing passages. Seal using silicone sealants (for smaller gaps) or polyurethane foam (for bigger gaps). These passages are often hidden so don't forget to look behind kitchen and bathroom cabinetry and inside wardrobes and hot water cupboards.
  • Extractor fans and rangehoods. Models with backdraught shutters help prevent draughts - if you have them, check that the backdraught shutter is working properly.
  • Air leakage through some recessed downlights. Air leakage and heat loss can be a real problem with older style recessed downlights. Up until mid-2012, most styles of downlights could not be sealed or covered as it could cause a fire hazard, so holes were required in insulation to create a safety barrier preventing this.  The best solution is to replace these old style downlights. Surface mounted or suspended light fittings allow you to plug the holes in the ceiling and can be insulated right over, and all downlight fittings introduced after mid-2012 are able to be insulated up to or over the top of.

Choosing and fitting weather stripping

You can seal up gaps around openable wooden windows and doors with weather stripping - it's cheap to buy and easy to install. Common DIY weather stripping products available from selected hardware and online stores include:

  • Self-adhesive foam draught seals. These are quick and easy to install, but become less effective over time due to permanent set (memory). They are available in varying thicknesses to suit different gap sizes.
  • Self-adhesive V-seal. This is made from a plastic strip that is folded into a V-shape and molds itself to the gap. It is very versatile as it fits a wide range of gap thicknesses, is effective for uneven gaps and can be used for both hinged and sliding doors and windows. [The Warm Up New Zealand: Heat Smart programme] uses V-seal type products.
  • Self-adhesive soft rubber seals. These provide durable compression seals and come in varying shapes and sizes to suit different applications and gap sizes.
  • Self-adhesive soft woven pile draught seals. These are suitable for sliding door and window applications. Make sure you choose the right product for the job, and the right thickness. Measure the size of the gap by opening the door or window and seeing how many pages of a notepad, magazine or book you can fit into the gap. Then measure their thickness. Clean the paint surface before installing self-adhesive seals or the strip won't stick.
  • Traditional single or double-hung windows can be difficult to seal. You can seal any that you no longer need to open with a suitable sealant.

Blower door test

For a thorough and accurate assessment of air leakage in your home, you can hire a qualified technician to conduct a blower door test. A blower door test, which depressurizes a home, can reveal the location of many leaks.

This test is usually only worth considering if you are building new or undertaking a major retrofit project so that you can actually seal any identified leaks effectively.