Timber Window Repairs window restoration Eastern suburbs Melbourne


DOUBLE GLAZING EXISTING WINDOWS

Why Double Glazing?

Double glazing can reduce temperature fluctuations by close to four times that of your standard glass.

To achieve this the double-glazed unit has to have the optimal gap of 12 mm, filled with argon gas, plus a Low “E” coating on one side of the unit.

Low “E” coated glass (low emissivity coated glass) results from a manufacturing process where additives are baked into the glass. It will absorb nearly half of the sun’s energy directed onto it in summer, and in winter it can reflect 85% of the room’s temperature back into the room. Plus, it is clear.

The insulating properties of glass are measured in its “U” Value.
Your standard 3-4 mm clear glass has U Value rating of 5.9.
However, a double-glazed unit with: 4mm glass/12mm argon-filled space/4mm “e”-coated glass, has U Value of 1.6 (the lower the number, the better). The total thickness of this unit is 20 mm.

If your window cannot accommodate the thicker glass, we recommend the use of a laminated glass called Comfort Plus. In its standard form it is only 6.38 mm thick and has the Low “E” coating on one side. Its U Value is 3.6.

Secondary glazing

We talk of secondary glazing when you leave your existing glass in place and install new glass on the inside of the window frame. The larger 70 or 100 mm gap is very desirable for noise reduction. If for example you used the Comfort Plus in this situation your U Value would be around 2.3.

Noise reduction

A product called V-Lam Hush can be installed into old double-hung sash windows. It starts at 6.5 mm thickness and can reduce noise by up to 50%, compared to standard 3-4 mm glass. By including weather seals you will reduce even more noise, as well as draughts.

Safety & Security

Any glass below 500 mm from floor level, if removed, must be replaced with grade A safety glass. The same applies to secondary glazing at floor level. In the price list below you will see a double-glazed unit with two layers of safety glass. It has a U value of 1.6 and is very secure. For example, the windscreen of your car is also laminated glass.

From here we need to talk about the right type of glass for your situation and cost per metre.
This can be done over the phone or it may require an onsite visit.
If you measure your own glass, use the method below to calculate price.

Estimate your own price

Measure each glass pane in millimetres, e.g. 887 x 887
Calculate 0.887 x 0.887 = 0.786 square metres.
Multiply 0.786 x Cost of glass e.g. $250 Answer = $196.50