The Digest indicates how an assessment can be made of the probable fuel consumption and hence the running costs of house heating systems during the normal heating season. It discusses the various forms of heat loss and heat gain.

Given the average seasonal temperature difference between indoors and out, the conduction and ventilation heat losses, the miscellaneous heat input from ancillary sources, the "house efficiency" of the space heating system, and the calorific value of the fuel, it is possible to estimate the annual heat requirements and fuel consumptions for a variety of conditions.

X