New construction may not be using these exact windows – but they have to be title 24 compliant – which means they are almost 100% guaranteed to use energy efficient windows. This has been true for several years. We were applying for the permit for our granny flat in 2006/2007 – and had to comply with changing standards on the title 24 requirements. The 2005 requirements came into effect while we were mid-review of the permit – and we had to make changes. The 2008 requirements went into effect 1/1/2010.

(I apologize – I think I referred to title 20 someplace else. It’s title 24).

It encompasses a lot more than windows – and I suppose if absolutely everything else was super efficient, you might not need the argon filled windows – but it gets you the best bang for your buck when doing the calculations.