Retrofitting double glazing

Double glazing reduces heat loss through the window by around 50% (depending on window type). There is a misconception that homeowners should replace windows with double glazed units, however this is not practical or cost effective for many householders. Retrofitting double glazing, however, can be a good affordable option in many cases.

Shrinkfit window film

A thin film of cellulose sheeting is attached with clear double sided sticky tape to the window frame (leaving a space between the glazing and the film). The film is then heated and shrunk which effectively converts the window to a double glazed unit. To apply successfully the window structure must allow a beading of timber to be installed or already have a flat surface spaced between 6 to 12 mm from the glazing to which the film can be secured (with supplied double sided tape). The film is not suitable for very large expanses of glass or in areas with a lot of traffic as the film is reasonably fragile and prone to damage from sharp objects. In Australia internal film is available from ClearComfort directly or can be purchased on-line (e.g. as 3M window film interior or Duck window film interior. However if desired external films can be ordered on-line, broadening the application.

Perspex DIY

More expensive than Clear Comfort but still an affordable option in many circumstances is to install a sheet of perspex as a double glazing. A sheet of perspex cut to size can then be installed as the secondary glazing allowing a gap between the glass pane and the perspex (perspex can be fitted either inside or outside the glass glazing). The perspex can be attach with either magnetic strips or screws. Applying a rubber weather seal strip may improve the air tightness of the perpsex glazing. The double glazing can be removed for cleaning or storage over the warmer summer months if desired.

Perspex can be sourced and cut to size by plastic manufacturers. The thickness required will depend on the size of window. Small to medium windows 3 mm perspex will be adequate. larger wnidows may require 5 mm perspex.

Professional retrofitted double glazing

MagicSeal and Magnetite are proprietory brands of retrofitted double glazing. Magnetic strips are applied to the window frame and the acrylic sheet cut to size. The double glazing then attached to the magnetic strip, allowing it to easily removed for cleaning or when not required. These systems are effective for heat retention and sound control. While reaonsbly expensive the finish is professionla and less hassle than replacing windows.

Other options

Many window panes are poorly sited and provide no view or solar gain. These windows can be improved very effectively by the methods described below. Often ceiling to floor windows have a lower pane which is non functional and these panes can be blocked. These methods are particularly useful in rental properties as they are cheap to apply or install and quick to remove.
  1. Cut bubble wrap plastic to the size of the galss pane and place bubble wrap, blister side to pane, against the window.The wrap stays in place by static and results in an instant and reasonably effective double glazing. large rolls of bubble wrap available from Australia Post Shops, Office Max, Office Works and other stationary suppliers and some hardware stores.
  2. Cut polystyrene board to size and block window pane with board. Polystyrene board can be colelcted from businesses thatr eceive large packaged items.

ClearComfort is available directly from the wholesaler Clear Comfort
Other thin film brands are available if you are prepare to purchase from international online stores such as
Various sizes and combinations of both internal and external shrink film window coverings are made by 3M, Duck, FrostKing.

Perspex can be cut to size from plastic manufacturers e.g.

Access Plastics
24 Pearl St, Derwent Park
Ph 6272 3105

Associated Plastics Tasmania
1 Birdwood Ave, Moonah
Ph 6272 0744

Eagle Plastics
320 Elizabeth St, North Hobart 7000
Ph 62342030

Tasmanian Plastics and Fibreglass

452 Rifle range road, Sandford
Ph 6248 9990

Professional retrofitted acrylic double glazing.
36 Bass Hwy
Cooee, TAS 7320
Phone: (03) 6432 1058

125 Albert Road
Moonah TAS 7009
6278 8887