Farewell to gas: Ex-post evaluation of a case study replacing a boiler with a heat pump solely based on available smart meter data

Overview & Synopsis

Electrifying end-uses by replacing fossil fuels is crucial in Europe to achieve carbon neutrality by 2050 and enhance energy independence. This study focuses on the replacement of an old natural gas-fired boiler with an air-to-water heat pump for both space heating and domestic hot water (DHW) in a large, historic house (circa year 1500).We assessed the energy savings from this replacement by monitoring daily electricity consumption via an existing smart meter over two distinct periods: two years with the gas boiler (for heating and DHW) and over a year post-retrofit with the heat pump (covering heating, hot water, appliances, and cooking). Initial gas consumption data for space heating and hot water allowed us to evaluate the impacts of this transition in terms of energy use, CO2 emissions, and financial implications. To quantify energy savings, we employed a multivariate regression model to adjust the baseline for actual weather conditions. Our findings indicate an increase in electricity consumption of approximately 50 kWh/m², which is largely offset by the elimination of gas consumption (around 300 kWh/m²), both in energy and monetary terms. Notably, CO2 emissions were reduced by over 80%, aligning with results from similar case studies.Additionally, we analysed the thermal gradient (power demand relative to outside temperature) to understand the heat-sensitive consumption patterns, primarily associated with space heating and hot water. This analysis was compared with other houses of varying ages (recent, intermediary) to illustrate the variability in thermal sensitivity based on insulation quality.