The combustion air correction accounts for the heat credit from preheating combustion air. Higher preheat temperatures reduce fuel consumption by providing sensible heat to the combustion process. The correction is applied to both stoichiometric and excess air. The base constant is the same as the air correction base.

\begin{equation}\label{eq:o2-enrichment-combustion-air-correction} CAC = (k_{base} + C_{p,air} \cdot T_{air}) \cdot (1 + EA)\end{equation}

Symbols

\(CAC\)	Combustion air correction \([\unit{ \percent}]\)
\(k_{base}\)	Combustion air correction base constant (-1.078913827) \([\unit{ \btu\per\pound}]\)
\(C_{p,air}\)	Air specific heat \([\unit{ \btu\per\pound\per\degreeFahrenheit}]\)
\(T_{air}\)	Combustion air preheat temperature \([\unit{ \degreeFahrenheit}]\)
\(EA\)	Excess air \([\unit{ \unitless}]\)