1. A method for determining an appropriate parameter order for an energy use model for a building site, the method comprising: receiving an energy use model for the building site at a communications interface of a building analysis system, the energy use model comprising a weather-related predictor variable; obtaining, by a processing circuit of the building analysis system, a plurality of data points, each of the data points comprising a value of the weather-related predictor variable and an associated energy consumption value for the building site; calculating, by the processing circuit, a first regression statistic indicating a fit of the energy use model to the plurality of data points under a null hypothesis that the energy use model has a first parameter order and a second regression statistic indicating a fit of the energy use model to the plurality of data points under an alternative hypothesis that the energy use model has a second parameter order different from the first parameter order; generating, by the processing circuit, a test statistic that is a ratio comprising an improvement between the first regression statistic and the second regression statistic; comparing, by the processing circuit, the test statistic to a threshold value to determine whether the improvement warrants rejecting the null hypothesis; determining, by the processing circuit, an appropriate parameter order for the energy use model based on a result of the comparison; receiving, at the processing circuit, inputs from one or more sensors that measure a variable state or condition of the building site; using the energy use model with the appropriate parameter order to generate, by the processing circuit, control signals for one or more building control devices as a function of the inputs from the sensors; and operating the building control devices according to the control signals, wherein operating the building control devices affects the variable state or condition of the building site.