This study evaluates the impact on energy consumption and GHG emissions as well as the technoeconomic feasibility of retrofitting solar domestic hot water (DHW) heating systems to all houses in the Canadian housing stock (CHS). The study was conducted using the Canadian Hybrid Residential End-Use Energy and GHG Emissions Model (CHREM). It was assumed that all houses that have a DHW system with a tank, and a roof facing south, south-west or south-east could be retrofitted with a solar DHW system. As to be expected, the energy and GHG emissions impact of retrofitting SDHW systems into the CHS is substantial. If all eligible existing DHW systems (30% of those existing in the CHS) were to be retrofitted with SDHW systems, the energy consumption and GHG emissions of the Canadian residential sector would be reduced by about 2%. This is equivalent to 22.7 PJ of end-use energy savings and 1 Mt of GHG emissions reduction, or 11.8% and 11.9%, respectively, of the current amounts associated with domestic hot water heating. The energy savings potential with SDHW systems in all provinces are similar, while the GHG emission reductions vary significantly due to the substantially different fuel mix used in different provinces. The economic feasibility results demonstrate the impact of installation and fuel costs, as well as interest and energy price escalation rates on payback period. (C) 2014 Elsevier Ltd. All rights reserved.