## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Reference** & **Building Type** & **Forecasting Category** & **Forecasting Method** & **Model** & **Input Variables** & **Prediction Horizon** \\ \hline \multirow{2}{*}{[87]} & \multirow{2}{*}{Nonessential} & \multirow{2}{*}{Whole-building energy} & \multirow{2}{*}{Hybrid} & \multicolumn{2}{c}{Principal component} \\  & & & & analysis, Auto-regressive, & & \\  & & & & Orthonormal partial least & & Historical + Calendar & Long-term \\  & & & & & squares. & & \\ \hline
[88] & Nonessential & Whole-building energy & Hybrid & Elman neural network & Historical + Calendar & Medium-term \\ \hline
[89] & Nonessential & Other & Hybrid & K-means, ARIMA & Historical + Calendar & Short-term \\ \hline
[90] & Residential & Whole-building energy & Hybrid & k-means, LSTM & Historical + Calendar & Short-term \\  & & & & Networks & & \\ \hline
[91] & Nonessential & Whole-building energy & Hybrid & LSTM RNN & Historical + Calendar & Short-term \\ \hline
[92] & Both & Whole-building energy & Hybrid &
\begin{tabular}{c} Convolutional neural \\ Network with LSTM \\ autoencoder \\ \end{tabular} & Historical + Calendar & Short-term \\ \hline
[93] & Nonessential & Cooling energy & Hybrid &
\begin{tabular}{c} Chaos SVR, Wavelet \\ decomposition SVR \\ \end{tabular} & Historical + Calendar & Short-term \\ \hline
[94] & Nonessential & \begin{tabular}{c} Cooling and heating \\ energy \\ \end{tabular} & Hybrid & \
\begin{tabular}{c} SVR, Partial least squares \\ regression \\ \end{tabular} &
\begin{tabular}{c} Historical + Weather \\ + Calendar \\ \end{tabular} & Short-term \\ \hline
[95] & Residential & \
\begin{tabular}{c} Cooling and heating \\ Energy \\ \end{tabular} & Hybrid &
\begin{tabular}{c} Fuzzy inductive \\ reasoning, Adaptive \\ neuro-fuzzy inference \\ system \\ \end{tabular} & Historical + Calendar & Short-term \\ \hline
[101] & Nonessential & Whole-building energy & Hybrid &
\begin{tabular}{c} GP Regression \\ \end{tabular} & Historical + Calendar & Medium-Term \\ \hline
[96] & Residential & Whole-building energy & Hybrid &
\begin{tabular}{c} Least squares SVR, radial \\ basis function Neural \\ Network \\ \end{tabular} & Historical + Calendar & Long-term \\ \hline
[97] & Nonessential & Whole-building energy & Hybrid &
\begin{tabular}{c} LSTM neural network, \\ Sine Cosine optimization \\ algorithm \\ \end{tabular} & Historical + Calendar & Long-term \\ \hline
[98] & Nonessential & Whole-building energy & Hybrid & ANN, SVR &
\begin{tabular}{c} Historical + Weather \\ + Occupancy + \\ Calendar \\ \end{tabular} & Long-term \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._ \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Reference** & **Building Type** & **Forecasting Category** & **Forecasting Method** & **Model** & **Input Variables** & **Prediction Horizon** \\ \hline
[99] & Nonessential & Whole-building energy & Hybrid &
\begin{tabular}{c} Deep belief networks, \\ Extreme learning \\ machine \\ \end{tabular} & Historical + Calendar & Very short-term \\ \hline
[100] & Nonessential & Whole-building energy & Hybrid &
\begin{tabular}{c} Deep deterministic policy \\ gradient, Recurrent \\ Deterministic policy \\ gradient \\ \end{tabular} & Historical + Weather & Short-term \\ \hline
[102] & Nonessential & \
\begin{tabular}{c} Cooling and heating \\ energy \\ \end{tabular} & Hybrid &
\begin{tabular}{c} Autoregressive particle \\ swarm optimization \\ neural network \\ \end{tabular} & Historical + Weather & Short-term \\ \hline
[103] & Both & \
\begin{tabular}{c} Cooling and heating \\ energy \\ \end{tabular} & Hybrid & xbyC models &
\begin{tabular}{c} Historical + Weather \\ + Calendar \\ \end{tabular} & Short \\ \hline
[104] & Residential & Whole-building energy & Hybrid & \
\begin{tabular}{c} RNN with gated \\ recurrent unit \\ \end{tabular} &
\begin{tabular}{c} Historical + Weather \\ + Calendar \\ \end{tabular} & Short-term \\ \hline \end{tabular}
\end{table}