Home Forums General Discussion Double Glazing – Retrofits Reply To: Double Glazing – Retrofits

Vicki Cowan

Hi Scott,

Just mooching in best practice library for Energy Cultures research as meeting them this week and saw your post.  I have personal experience here as well as Beacon insight.  We retrofitted double glazing in our double hung sashes at home and doing the rest as part of a massive renovation we’re doing (have I got lovely pictures of my retrofitted wall insulation or what!).

I don’t know of a simple pathway document, perhaps we should be challenging ourselves in the HUB to develop one..why not have a go and we all edit and contribute? here’s some started points… Hows’ this for a potential structure to help homeowners make a decision (isn’t that what we are trying to help them do?)

outcomes sought (warmth, sound, saving furniture from sun, overall maintenance upgrade…more?)
consider windows in wider upgrade plan: i.e. assume already done ceiling, underfloor insulation? considering wall insulation too (YES do it for warmth and energy savings!)
window maintenance (build into plus side – you were going to have to deal with this sometime!)
aesthetics (if front picture window might be prepared to spend more than on a toilet window facing back yard?)
total budget envelope (!),
technical choices: secondary vs retrofit double glazing, frame choice, glass choice
Add thermal curtains (I still have tight fitting curtains on my double glazed windows..I do live in Welly!).  remember pelmets and floor length and decent thermal drapes!

Lois and I have written about our own homes in HomeSmart Renovation newsletters.  I ahve provided links – hope they work here?


So choose Low E glass!

decide on frames (make sure thermally broken!)

Secondary vs double glazing – factor in cost…double glazing was coming down when this was written.


bit I wrote about mine at the time in those newsletters


We decided to retrofit into wooden frames.  Lynda Amitrano from BRANZ told me during a work meeting at my kitchen table that my glass looked original ~1901!  Gravity was doing it’s work on that glass!  So the windows were due some maintenance and owed me nothing..!

I asked my tradesman to ‘give me the whole package’ and convinced him to paint windows while he had them (he tried to save me money, but it would have been an enormous pain and inefficient to do after he’d re-installed so he went off with my left over paint tins from under house and I received a full window solution).  Also his joiner did a great job of addressing some of my old house movements which had created gaps as they reinstalled…  I would recommend double glazing: rooms warmer and quieter (not to be underestimated feature!).

Hope this helps!