Annual Fuel Utilization Efficiency
Annual Fuel Utilization Efficiency Formula | 
||
| 
 \( AFUE \;=\; \dfrac{ E_o }{ E_i } \cdot 100 \) (Annual Fuel Utilization Efficiency) \( E_o \;=\; \dfrac{ AFUE \cdot E_i }{ 100 }\) \( E_i \;=\; \dfrac{ E_0 \cdot 100 }{ AFUE }\)  | 
||
| Symbol | English | Metric | 
| \( AFUE \) = efficiency | \(dimensionless\) | \(dimensionless\) | 
| \( E_o \) = output energy | \(Btu\) | \(kg-m^2 \;/\; s^2\) | 
| \( E_i \) = input energy | \(Btu\) | \(kg-m^2 \;/\; s^2\) | 
Annual fuel utilization efficiency, abbreviated as AFUE, a dimensionless number, measure the efficiency of a gas furnace or boiler will operate over an entire heating season.

