The Cambridge Housing Model is a bottom-up building physics model for estimating total annual domestic energy consumption for England and the UK. The model is SAP 2009 based, uses the English Housing Survey as the main data source and takes account of monthly/regional variations in external temperature and wind speed. We have conducted a one at a time sensitivity analysis on parameters in the model in order to appreciate their relative significance on our estimates. We have further assessed the linearity of the response of the model to variations in individual parameters, and the additive nature of multiple parameter changes applied individually compared to changes applied simultaneously. We have undertaken an uncertainty analysis based on Monte Carlo random sampling, using a simple approach to generate indicative results. We outline the uncertainties considered, the expert judgment-based distributions applied to those uncertainties, and the resulting output distributions of estimates for total energy, total gas and total electricity consumption in England in 2009. This work relates closely to the uncertainty for SAP assessment of new homes for the Building Regulations, and estimates of energy savings to be used in the Green Deal.