ABSTRACT
The cost of mechanical services in £ m-2 of treated floor area has been extensively used for budget price indications and proved of some value with office blocks but of less worth in other applications. The U-values of the structural elements in the fabric are generally of less importance, except in the case of low rise-buildings having large plan areas, for example, hyperrnarkets, where the thermal transmittance of the roof is significant. The technique currently most favoured for this is the present value method. This consists of establishing the discounted cash flow throughout the life of the plant by converting all future expenditure and income into an equivalent sum of money at present day values, allowing for inflation and for the interest that must be paid on borrowed capital. To obtain a realistic view of the engineering economics of a system all the financial outgoings and receipts must be accounted over its estimated life.
