London Residential Smart Hybrid Heating Pilot: System Performance Analysis

This report presents performance analysis results for Enbridge and London Hydro’s smart-switching hybrid heating pilot conducted in London, ON, implemented in late 2021. Each smart-switching hybrid system included an air-source heat pump (ASHP), a backup furnace, and a smart-switching thermostat. ASHPs are an alternative home heating and cooling option that look and function similarly to an air conditioner.

The systems sought to achieve the lowest possible heating costs for homeowners. Based on factors like outdoor air temperature, expected ASHP efficiency, and time-of-use electricity bracket, the thermostat was designed to select, in real-time, the heating source for the home (furnace or ASHP) that was expected to achieve the lowest cost of operation.

The pilot included 105 homes, but this performance analysis study focused on eight homes where additional sensors were installed by Enbridge and London Hydro. Overall, the analysis showed that the ASHPs reduced utility bills, provided most of the home heating needs, lowered carbon emissions, operated efficiently, and did not significantly impact the annual aggregated peak electricity demand of the homes.

Smart-switching systems can be improved in future installs by (i) avoiding unnecessary defaulting to the furnace, (ii) optimizing ASHP sizing for colder temperatures (including in this is contractor training), and (iii) incorporating carbon reductions in thermostat algorithms.

Overall, this study builds confidence in ASHP technology and provides further data and analysis to show that they are indeed high-performance devices that can reduce carbon emissions and homeowner utility costs. Funding support from The Atmospheric Fund for this analysis is gratefully acknowledged.