Triple glazing in offices increases carbon footprint
Exclusive whole life carbon research shows extra cost is not offset by emissions reductions
Fitting triple glazing in offices to reduce emissions is a waste of money because it increases the building’s carbon footprint, exclusive research for Building has revealed.
The use of triple glazing has increased in recent years to meet tough energy regulations and was used on the Heron Tower, in the City of London, and The Shard, on the south bank of the Thames.
However, research by whole life carbon assessor Sturgis Carbon Profiling and cost consultant Gardiner & Theobald, showed fitting triple glazing cost an additional £80/m2 and increased whole life carbon dioxide emissions by 23kg/m2 compared with double glazing.
This is because the additional energy used in manufacturing the triple glazing, when compared with double glazing, is not offset by the energy savings in use.
For the exclusive research in full see Building’s data section here
Gareth Roberts, director of Sturgis Carbon Profiling and one of the authors of the report, said the outcome was a consequence of trying to meet the targets in PartL of the Building Regulations.
“That marginal benefit you need to meet the requirements can end up doing more harm than good,” he said.
The study compared a standard prestige office with one optimised for whole life carbon reductions using emerging CEN/TC 350 suite of standards, which sets out a methodology for measuring whole life carbon and includes embodied, construction, operational and end of life disposal emissions.
The research showed the whole life carbon footprint of an office could be reduced by 16% for a cost increase of 1.4% when whole life carbon analysis is used in its development. The same carbon reductions would cost 7% more if delivered using renewables.
It revealed only fitting triple glazing to the south and west elevations of offices cost an extra £40/m2 and reduced whole life CO2 emissions by 4.2 kg/m2. Roberts said there were more cost effective ways of reducing whole life carbon.
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Readers' comments (3)
Same old story, every time government interferes, it all goes wrong. The entire carbon-capture and low-energy effort has been compromised by lab-type theory and big-business at the behest of big government. From the electric car to the solar panels, to triple glazing and forced mechanical ventilation, the bottom line true cost and energy use is always way too high. (If you made the buildings smaller and cheaper, that might help.
Energy should be charged at the correct rate, so the market is forced to introduce the right products. Just like loading the petrol / diesel price to reduce car and truck travel and encourage low consumption engines, loading the energy tariffs to promote low-energy solutions is all you have to do. If you want to encourage progress just tax the obsolete; forget the grants and subsidies, they are always stolen by the greedy.
Keep the Building Regs simple, U-values and daylight only.
This is a world which is going to need more freedom of choice and less government control, not more. Remember, we are now a third-world economy.
Surprised? No. Also If whole life costing were used on Wind Power, especially the ones at sea with huge maintenance costs, would they pass the test?
Initially Part L was reasonable, and did bring a few necessary points into legislation, but now it is way OTT.
Many of these new "targets" are set by the EU, what are the other countries doing towards achieving them, or are they just paying lip-service while good old UK jumps up and down to comply-however stupid the concept.
I do agree we need more freedom of choice and less government control (the infamous Health and Safety being another example-bring back common sense), but as a pensioner I must look in horror at the suggestion to massively increase energy tariffs.
This study seems to be a bit one-dimensional - in reality, things are a bit more complicated. I have calculated the environmental impacts of different glazings for many buildings, incorporating different aspects. Here are the most important three: First, thermal comfort. Very often, one simply needs triple glazings because of surface temperatures in winter (alternatively, you could place a radiator underneath the window, but that's in most cases far worse regarding carbon emissions). Second, the energy balance depends on solar radiation and gains. If you are in a place where the sun shines very often during the winter months, and you can use most of the passive solar gains (building with lots of thermally active mass, temperature tolerance of users), then triple glazing is not suitable because of the lower g-value and hence the lower gains that can't be outweighed by the lower losses (lower U-value). But if the building or the windows are situated in a place where the losses are far greater than the gains (i.e. north facade), triple glazing can be an efficient measure for lowering CO2-emissions. Third: the heating system. The higher energy losses of a double glazing during winter time must be compensated by the heating system. If you have a super efficient heat pump that consumes only green power, then triple glazing will very probably not look appealing. But if the heating system is based on fossile fuels, then the CO2-balance will be very different and triple glazings will be a measure to take into consideration.