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Draught Proofing

New Zealand homes are notoriously draughty, especially those built before 1960 with wooden floors and window frames. In an insulated home 10-17% of heat is lost through draughts as warm indoor air escapes and is replaced by cool outdoor air. This figure can be much higher in older houses particularly in windy weather.

The most common source of draughts is gaps around exterior doors and windows. Serious draughts can sometimes be noticed by curtains billowing during windy weather or if cold air can be felt by the hand or face around the frames. Smaller draughts can be detected by holding an incense stick around the inside of window and door frames and watching to see how the smoke behaves.

 

Fortunately most draughts can be reduced or eliminated using DIY draught proofing products which are available from most hardware stores. Read more about draught proofing products.  Some common sources of draughts and the best solution are outlined in the table below.

 

Source of draught

Solution

Available from

Gaps around wooden windows or doors

Install self adhesive foam/rubber draught proofing strips or v-seal.

Hardware stores or CEA online shop

Gaps around aluminium windows or doors

Replace rubber seals and or brush strips

Aluminium joinery manufacturer/installer

Gaps under exterior doors

Install weather seal or brush strip.

Hardware stores or CEA online shop

Gaps under internal doors

Install door sausages.

CEA online shop or home made

Gaps between wood floorboards

Install bulk insulation product underfloor.

Hardware store or Subsidised insulation through CEA

Gaps below skirting boards or between wooden wall linings

Silicone gap sealant/caulking or expanding foam for large gaps.

Hardware store

Keyholes in exterior doors

Install keyhole cover.

Locksmith

Loose fitting Cat door

Replace with close fitting cat flap with brush seals and magnetic return mechanism to stop door blowing open

Hardware store or pet store.

Recessed downlight fittings

Replace with non recessed light fittings or with CA (closed abutted) downlight fittings (installed by electrician).

Lighting/ electrical supplier or hardware store.

Extractor fans

Install a backflow damper for ducted fans or gravity louvre for through wall fans.

Hardware store or ventilation supplier

 

 

 

FAQs

If I seal up all the draughts in my house won't it reduce ventilation?  It is preferable to control ventilation of your home by opening windows and doors as needed than to rely on draughts. Draughts do provide considerable passive ventilation, but cannot be controlled. The rate of air change will depend mainly on the wind conditions, in windy weather there will usually be too much ventilation leading to excessive heat loss. Draught proofing your house allows you to have greater control over ventilation rates. Read more about ventilating your home (link to CEA ventilation page)

 

Since draught proofing my home the condensation on the windows has got worse. What is happening? Sealing up the draughts has reduced background ventilation in your home. It is important to ventilate your home daily by opening windows and doors. Read more about ventilating your home (link to CEA ventilation page). It is possible that excessive ventilation from draughts was masking problems with moisture produced in the home. It may be necessary to address sources of moisture within the home to reduce condensation. Read more about solving dampness and condensation problems (link to CEA dampness and condensation)

 

 

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