Energy analysis and optimal insulation thickness.

The problem of optimal insulation thicknesses is one of the simplest that can be addressed by energy analysis. The authors begin with a simple analytical approach, and go on to describe detailed numerical work, based in the definition and parameterisation of a standard dwelling. Sensitivity of the results to large uncertainties in embodied energy data and building lifetime are investigated. The first conclusion is that insulation thicknesses in UK buildings are suboptimal in energy terms. This conclusion appears to be robust. Energy optimised dwellings ln the climate of the UK would use more than 90% less energy for space heating than dwellings built to current standards. The authors also show that the penalty for non-optimal design is asymmetric, with much larger penalties for sub-optimal Insulation thicknesses, than for super optimal thicknesses of insulation. This suggests that under conditions of uncertainty, it is rational to install more than the central estimate of optimal insulation thickness.