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RICS study shows true cost of Part L

The cost of building energy-inefficient homes has been laid bare by a new Royal Institution of Chartered Surveyors paper that shows the massive cost associated with adapting buildings to new carbon compliance regulations.

In October 2010, Part L of the Building Regulations (energy and carbon compliance documentation) was revised.

The new RICS information paper examines retrofit measures needed to upgrade buildings from 2006 to 2010 Part L compliance.

Faithful+Gould head of sustainability Sean Lockie, who was lead author on the report, said the research showed carbon savings far beyond what was expected, but that the costs associated should act as an incentive for buildings to be designed more efficiently.

Faithful+Gould carried out research on a 16-unit residential development, a 10,000 sq m office and a supermarket in the South-east of England built to comply with 2006 Part L building regulations.

Mr Lockie said: “The research shows how important it is to get the early design strategy right so you don’t have to go back and add elements to inefficient buildings.

“We were stuck with the buildings footprints where we had to add measures to get them to comply, but the costs would be lower if you were starting from scratch.”

The data showed that the supermarket delivered 38 per cent carbon savings with an annual cost saving in excess of £70,000 through measures including improved air tightness, boiler efficiency and lighting controls.

The offices made carbon savings of 37 per cent and cost savings of more than £32,000 each year through measures such as improved insulation and night cooling.

The residential case study delivered the least carbon saving at 25 per cent - still more than the 21 per cent savings expected by the government.

The predicted costs ran to £1.5 million for the office and more than £1m for the supermarket.

The report cited a number of routes to compliance under the new regulations, adding that those taken in any of the case studies “may not be the most cost-effective if a different strategy to the design of the building was taken”.

Building services engineer Grontmij said new Part L pressure testing regulations could add up to 60 per cent to the cost of developing residential property.

Grontmij senior design engineer Edmund Vaughan said: “The 2006 Part L rules allowed a representative sample of the pressure testing results to be used as proof of the dwelling emission rate, but the revised regulations do not.”

Stating that developers were getting a “nasty shock” from the cost of additional pressure testing, Mr Vaughan said a more practical solution to universal apartment pressure testing was required.