Interested that they are so critical of triple glazing.

Their argument seems to be that the high embodied carbon of manufacturing the extra pane of glass and the thicker aluminium frame, together with the likelihood of replacing the glazing several times during the building's life, means that the extra carbon spent on manufacturing the triple glazing is not any improvement on double glazing.

I'd have thought the answer might be to have smaller windows!

FWIW, the PH argument about 2G vs 3G tends to focus on solar gain vs insulation, and on minimum internal temperatures (to do with minimising convection) rather than embodied energy.

Posted By: djhFWIW, the PH argument about 2G vs 3G tends to focus on solar gain vs insulation, and on minimum internal temperatures (to do with minimising convection) rather than embodied energy.

Posted By: tony3g is now standard in central and Northern Europe, for good reason, it is far superior, more robust, longer lasting, economic.

This to me highlights a big glaring hole in the Passivehaus concept, and probably including 'highly energy efficient houses.' Rarely does embodied energy, and perhaps more importantly, life-cycle embodied energy including demolition, recycling and waste, come into the calculations. Given some of the materials used in some Passivehaus developments, this will account for a very significant amount. Until this is better understood, it's actually difficult, if not impossible to state whether 3g is superior to 2g over the lifetime of the house - especially in most of the UK.

Disclaimer and conflicting interest here - I do have 3g windows (at least they're timber framed) which I installed in January, so I take my own right to question the nature of my own decisions based on new information and thinking around this whole property development thing

Posted By: djhMany straw bale builders want everything to be natural and care less about the 'efficiency' of the building. I'm somewhat on a limb since I was more concerned about meeting a specific energy goal (PH) than about being natural or organic everywhere. And more concerned also about low maintenance.

So we too have 3g windows that are timber-framed; with plastic foam inserts to meet my performance criterion and aluminium external facings to meet my low maintenance criterion. Who knows what will turn out to have been the 'correct' path in the fullness of time and with the benefit of hindsight?

The best is the enemy of the good etc.

I think pretty much all of us can be envious of a strawbale PH

Posted By: djhFWIW, the PH argument about 2G vs 3G tends to focus on solar gain vs insulation, and on minimum internal temperatures (to do with minimising convection) rather than embodied energy.

And the lack of convection improves internal comfort and effectively increases the usable floor area. we have a couple of chairs that are very close to windows and still perfectly comfortable when sub-zero outside. I've worked in open plan, glass walled, offices where the desks against the window were noticeably cooler (to the point of some people having fan heaters under them). And this was in a, for the time, 'eco' building with semi natural ventialation (ie you could actually open vent panels in summer)

From that Guardian piece
"they have a huge amount of built-in obsolescence, given that their glazing systems are often only guaranteed to last for 30 years. You would expect these towers to last at least a century,� he says, “but they have a big embodied cost when these deep, triple-glazed units will have to be replaced so often.�

That's rather missing the point - Guarantee has nothing to do with expected life - it's not a 'mean Time to failure' and any manufacturer would want a very low claim rate at that point. With a 30 year guarantee I'd expect most to last more like 50 years. The issue with commercial buildings seems to be that the *planned life* of the buildings is often only 20-30 years and stuff tends to get pulled down and replaced after that. You see quite a few buildings being stripped to steel frame and rebuilt - I was told that environmental regs mean once a refurb goes beyond a certain (cost?/level?) the building has to be upgraded to current insulation standards and it becomes more viable to completely rebuild.

Residential is rather different - no matter how badly built the way we own resi buildings means theres very little demolition however poor the build.

Such a shame the new UK building regs almost outlaw timber. They could have at least designed the structure in CLT.

Posted By: ShevekSuch a shame the new UK building regs almost outlaw timber.

In what way?