Heating Factor

A heating factor may be helpful in intrepreting results of building energy modeling by boiling down the heating performance to one simple number.   It is very innacurate and only a mild approximation of what is happening to the building.  However, calculating it can be useful in determining the normal heating costs of a building.   The method is very location specific as building heating loads change from climate to climate.  

Heating Factor =       Btu      

                              HDD * SF

     Where: Btu  is the utility energy used in units of Btu to heat the building, including inefficiencies etc.

     HDD = Heating Degree Day, For example:  NYC is 4805.  See ASHRAE 90.1 2004 for a list of HDD's for each region

     SF = Building heated square feet.

Typical Building heating factors:

Heating Factors for NYC area:  (data generalized from experience, not from case study or other formal data) 

     New Construction:  8 or 10

     Superior New Construction:  5

     Existing Buildings:  16-20

     NYC average:  12-13