One of the first avenues we explored was the world of double glazing. There are alot of windows in the house all of fairly generous proportions. They are of timber construction and are double hung (sash). Most of them work with a few that need new sash cord or have minor cracked glass. They all sucked the cold air through the glass with gusto.

Coming from the UK Sean was very used to double glazing being the norm and not the unusual. Tasmania being of similar weather conditions to the South of England the thought was that double glazing might be more common than the rest of Australia. This was borne out by a quick scan of the Yellow Pages.

There are many frame materials used in double glazing; aluminium, timber, and uPVC are the most common. The thermal efficiency of windows and their frames are measured in U values. A very comprehensive explanation of windows and their properties, (including curtains and pelmets) is available here, in fact is a great resource for all things in home renovation. The other places to check are the Window Energy Rating System (WERS) website and the Australian Window Association website. They have lots of information and links about windows and double glazing as well as the standards that window manufacturers need to meet.

Basically we arrived at the conclusion that aluminium framed windows, double glazed or not, were thermally very inefficient, timber frames are higher maintainence as they need regular painting or oiling so uPVC looked to be the way to go. uPVC is a material used extensively in Europe and the US.

In the North of Tasmania there are four suppliers/manufacturers of this type of window. Titane Windows (manufacturers uPVC), Launceston; Clark Windows, Smithton, Tas, 03 6452 2317; Certainteed WIndows, Martin Ruzicka, 0448 266 896.

We found out from Certainteed and then from Titane that they provide a unit replacement, which means that they only replace the windows and not the frames which in our case were timber. Only Certainteed made double hung units. Titane make an Austrian design of “tilt & turn” window. Both were ideally suited to our needs but at nearly $20,000 for the house was a budget breaker. As I was discussing this with the energy efficiency expert, Wayne Gorman, he mentioned that as the frames were timber they would have a fairly low U value (lower is better) and that you can get good results thermally wise from installing good quality thermal curtains and pelmets to create a still air space between the window and the curtains. (When we moved in there were only verticals).

The quote from Decorama Launceston, 43 Boland Street, LAUNCESTON TAS 7250 , Ph: (03) 63314949,  for our curtains (full length to the floor), tracks, and all the curtain tape, hooks etc was only approx $3200. We will have to fit them and make the pelmets. The thought is now that we can always retrofit doubleglazing later on if we need to but the curtains are something that we would need anyway. Decorama took our order for the curtains at the beginning of October 2008.

4 thoughts on “Windows

  1. Pingback: Thermal Curtains and Drapes: Do They Work? - Curtains Draperies

  2. Hi Guys, just found your story in an old copy of Owner builder, as ‘real builders’, not our usual reading. The best option for your windows, and cheapest in the lomg run, is to replace the glazing with double glazed units. Southern Glazing in Hobart make them regularly for us to retrofit to timber windows. timber windows are easy – just make a deeper rebatein the existing frame for all the fixed panes (and do you really want all those fiddly little sashes?). For the sash windows, just get your local joiner to make up new sashes, with rebates deep enough to take the DGUs. This retains most of your old windows. Wood is the best insulation product for windows, despite the high maintenance. Thick curtains are fine at night, but you also need to close them on cold cloudy days to be effective, and that isn’t very nice to live in. If you decide to go the new window option, Titane windows (Tasmanian) are now very competitive on price. be wary of cheap ‘retrofit’ options, they are often not very effective (many give American R-values, which are much lower than Australian R-values)

  3. Hi Guys
    I just be reading about your renovation and about your windows. I sell and install this product and I thought this mite be of intrested to you. You can find my contact on our web site


  4. God bless Wayne Gorman…the big word here is independant. There is another alternative cheaper than heavy drapes, curtains and pelmets. For North Facing windows in cool climates, instead of replacing the whole window and still getting the view and sun…try Magic Seal…Sean may know the product in the UK as it has swept the world. Basically a special perspex that sits on the inside of the window frame creating the much needed air gap. Fantastic with noise too…the mooing etc in Westbury. Can reduce heat loss by 80% and still allows the bright light airy feel in the living rooms or the coldest south facing windows or even the toilet and laundry. The challenge with old timber windows is that the frames are energy efficient but the glass is too thin and old double hungs leak like sieves. Something to think about for your readers as it is very economical to do. see


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