It is important not to simplify the complex issues involved in the changes to Part L of the Building Regulations (AJ 8.3.01).
Super insulation is cheap, has low embodied energy, and when applied to terraces results in little land take and large reductions in the need for space heating.
We try to use 300mm of insulation as a minimum standard for external envelopes for most new build projects - providing a typical U value of about 0.11W/m 2
degreesC. We find this to be one of the most cost-effective energy- and carbon emission-saving measures.
The real problem is that commonly used simplistic thermal analysis tends to steer designers towards small window apertures in a lightweight and airtight construction, leading to claustrophobic and gloomy interiors.
However, if south-facing, low E triple-glazing, thermally massive airtight construction and a heat recovery ventilation system are used it is quite possible to reduce the thermal requirements of new homes to 10-15 per cent of the 1995 Building Regulations' average three-bed home.
Bill Dunster, Bill Dunster Architects/Zedfactory