Doubling up: Secondary glazing case studies

Fitting secondary glazing

We hear from a variety of householders about their window upgrades using secondary glazing and retrofitted films.

Film + DIY secondary glazing
by Jasper Lee

My wife Melissa and I purchased a three-storey 1980s double-brick townhouse in the inner eastern suburbs of Adelaide back in the middle of 2016. We were new to Adelaide, but quickly became aware of the climate extremes during summer and winter. As Melissa works at home, and we have a toddler at home as well, thermal comfort was important for us, and we wanted to achieve this in a sustainable manner. We had made some basic DIY draughtproofing upgrades at our last property, a rental, with the permission of our landlord, but really wanted to make major improvements now we owned our own home.

Prior to our purchase, the house had been rented out for several years and little had been done to improve its energy efficiency. We had a six-month overlap while we were still renting, so we had time to plan and execute our retrofit upgrades. We started with the low-hanging fruit first: draughtproofing doors, windows and skirting boards. We also took advantage of the support from REES, the SA government energy efficiency program, to upgrade all lighting from halogens to LEDs. We also discovered that the cathedral-style ceilings were missing any form of insulation, so improved this with blow-in Rockwool insulation.

The next things we tackled were the windows. We took a bit of a mixed approach, based on the window aspect and usage, and we staggered the upgrades over the time until we moved in. Our approach was also governed by cost. Replacing the windows or changing their sizes/position would have set us back in excess of $20,000, compared to the $2000 we spent on upgrading 14 window panes with window film and secondary glazing. We did replace a poorly functioning back door with an argon-filled uPVC double-glazed sliding door, because it needed to be replaced anyway; this cost $3300.

Read Jasper’s full case study and 3 other secondary glazing stories (on Magnetite, EcoGlaze and a DIY approach) in ReNew 143.