TY  - RPRT
TI  - Estimating the heating seasonal operating cost of residential hybrid heat pump systems, including units retrofitted to oil, gas and electric furnaces 
AU  - Domanski, Peter
AU  - Kelly, George E
PY  - 1980
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 80-2090
DO  - 10.6028/NBS.IR.80-2090
ER  -