Calculates the percentage of fuel saved by implementing the efficiency improvement, based on the increase in available heat. This value quantifies the benefit of the improvement in terms of reduced fuel consumption.

\begin{equation}\label{eq:pheic-fuel-savings} FS = \frac{AH_{new} - AH_{current}}{AH_{new}} \cdot 100\end{equation}

\(FS\)	Fuel savings \([\unit{ \percent}]\)
\(AH_{new}\)	New available heat \([\unit{ \percent}]\)
\(AH_{current}\)	Current available heat \([\unit{ \percent}]\)