To characterize the uncertainty in TEA and LCA results, probability distributions were defined for 154 input parameters for both photovoltaic and grid-tied configurations and used in Monte Carlo simulation. Latin Hypercube Sampling 41 was used to generate 10,000 sets of input parameters for each configuration and improvement scenarios. Input values for parameters were determined from the BOM, vendors, manufacturers, and literature; distributions of these uncertain parameters were determined based on the quality and consistency of data. We used more constrained uncertainty (+/-15%) for values provided directly from the BOM, and less constrained uncertainty (25% -35%) for costs and weights that were calculated, found externally on vendor or manufacturer websites, or when surrogates were used (e.g., tank specifications). A +/-20% uncertainty was applied to energy and labor requirements provided by the design team. Uniform distributions were used for all uncertainty ranges except when values were available from the literature and data supported a triangular distribution. To better understand the relative sensitivity of TEA and LCA results to each uncertain input parameter, Spearman's rank-order correlation coefficients were calculated. Additional details are provided in Section S7 of the SI.