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Archive for February, 2008

The housing minister, Caroline Flint has ‘confirmed’ the proposals for mandatory Code for Sustainable Homes assessments for all new dwellings from May 1 2008. (more…)

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There seems to be much confusion regarding the forthcoming status of the Code for Sustainable Homes. There are many references to Government making a Code assessment mandatory from April this year.

But is this truly the case?

(more…)

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Greenpeace has created their version of a model town, stitching together examples from all over the UK. It’s a very cool combination of flash pages with lots of case studies, animations, and videos. Worth a wander.

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At first glance, the green credentials of ground source heat pumps (GSHPs) look unquestionable: because you’re harvesting free heat from the ground, you can get up to four times more energy out of the system than you put into it. Sure, it runs on electricity, which is more carbon intensive than gas, but because of this favourable ratio of output-to-input (called the COP for coefficient of performance) the system should still emit less carbon than a gas boiler – in theory.

But the claimed benefits are reliant on incorrect assumptions. A new house will emit about the same carbon using a ground source heat pump as with a new gas boiler. Here’s why:

(more…)

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[update March 20: I’ve looked further into how SAP treats CHP and written it up here. So while the method described below is being used elsewhere in the industry, the criticism doesn’t apply to SAP.] 

I’ve written on this topic before but maybe I didn’t succeed in making clear just how far off the mark the standard method is when estimating carbon emissions from CHP. Why does it matter? Here are some reasons:

  • Right now, big developers and the Housing Corp are assuming CHP can get them to level 4 under the Code for Sustainable Homes and this may not be true.
  • These emissions figures can determine whether or not a scheme gets planning permission or passes building regs.
  • The nascent micro-CHP industry (expected to be worth £2billion per year across Europe) is using this flawed method to back up its sustainability claims. Changing from a commonsense approach to the much more forgiving “standard” approach explains why the first Carbon Trust interim report on the micro-CHP field trails was so bleak and the second was so rosy.   

There’s a good chance that, if I’m right and the standard approach is flawed, when the CLG and BRE realise their mistake, the rules will change, leaving public and private sector developers and the micro-CHP industry with a very costly mess to clean up. (more…)

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