Variable Base Heating Degree-Day Data
ABSTRACT HEATING degree-day (HDD) data are often used to estimate annual fuel energy requirements for heating buildings. Commonly, a base temperature of 18.3°C (65°F) is used for calculating HDD. This fixed-base data is generally not appropriate for structures housing livestock since the balance or base temperature of the structure can vary significantly from 18.3°C. A simplified technique, using fitted-curve equations, has been developed to estimate average annual heating degree-days as a function of base temperature and location. This paper presents the method of calculation and specific equations for 70 cities in the United States. In addition, generalized heating degree-day equations for 25 states are presented and discussed.