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Toronto planner Blair Scorgie.Corinne Hildebrandt

With the global community hunkered down in Glasgow at COP26 and the timelines for confronting climate change growing increasingly constrained, countries like Canada face tough choices, not just about policy fixes, but also what individuals can or should do to reduce their carbon footprint.

According to Canada’s climate inventory, natural gas accounted for almost half of all home heating energy consumption in 2017, and that proportion is even higher for water. And in Greater Toronto, according to the Atmospheric Fund, buildings generated about 42 per cent of all greenhouse gases, and much of that comes from natural gas furnaces and boilers.

Some homeowners are now trying to cut or eliminate their gas use by installing electric heat pumps. With natural gas prices rising because of global shortages and carbon pricing, the return on investment for such retrofits is beginning to look increasingly attractive.

Toronto planner Blair Scorgie, an associate at SvN Architects + Planners, discusses his recent project.

G&M: Tell me a bit about your house.

Blair Scorgie: The house is located in Leslieville. Built in 1891, the 2½-storey semi-detached contains a brick foundation and front façade, and wood-frame structure. The lot is 15 by 105 feet, with laneway access. Prior to our home energy retrofit, a central duct-based mid-efficiency natural gas furnace and main air conditioner serviced our basement through to second floor, and a ductless air conditioner and electric baseboard heater serviced our partial third floor. A mid-efficiency natural gas water heater provided hot water.

G&M: What made you decide to install electric heat pumps?

Scorgie: After purchasing the house five years ago, my wife and I faced a few inconvenient truths. All of our mechanical equipment was nearing the end of its functional life, and showing signs of failure. Our furnace was not appropriately sized, our ductwork was not appropriately configured and our house was suffering significant heat loss. This impacted our thermal comfort, and our energy bill.

When it came to deciding how best to proceed, the choice was clear. My wife and I are staunch environmentalists. We were not prepared to prolong our reliance on fossil fuels, and wanted to decarbonize and future-proof our house. We also wanted a system that was safer and less expensive to operate, and which provided improved thermal comfort.

Some homeowners are now trying to cut or eliminate their gas use by installing electric heat pumps.Blair Scorgie

G&M: What else have you done to improve the energy efficiency/carbon footprint of your home?

Scorgie: We have replaced all of our windows and doors with Energy Star Certified openings, sealed all openings, installed a smart thermostat, reinsulated portions of our roof, enclosed previously-exposed portions of our house with ICF foundation walls, insulated the underside of our basement floor slab, installed an energy recovery ventilator and replaced an aging washer and dryer with Energy Star Certified appliances. Additionally, we are in the process of insulating basement headers and walls, sourcing a battery backup system to purchase and store electricity from the grid during off-peak periods and replacing our aging refrigerator, dish washer and natural gas stove/oven with all-electric/induction-based Energy Star Certified appliances.

G&M: Do you have any advice on the order of operations?

Scorgie: As a starting point, I recommend undertaking an energy audit. It will establish a performance baseline, identify potential home energy retrofits, assist in prioritizing improvements and allow homeowners to qualify for the Canada Greener Homes Grant. However, I would generally recommend improving insulation and air tightness, if needed, before replacing mechanical equipment.

G&M: Did you get an energy audit, and what did you find out from it?

Scorgie: Yes. Preliminary results reveal that our house used about 151 gigajoules of energy per year prior to the replacement of our equipment, and emitted approximately 6.1 tonnes of greenhouse gas (tGHG/yr) annually. Following the work we did, we anticipate a total energy reduction of about 82 GJ/yr, and total emissions reduction of 5.4 tGHG/yr. This brings our total emissions to 0.7 t GHG/yr – an 88-per-cent reduction.

G&M: Did you go with an all-electric heat pump or a hybrid system?

Scorgie: Our new equipment is entirely electric. A large central duct-based air-source heat pump (Mitsubishi Electric SUZ / SVZ Series Multi-Position Cold Climate Hyper-Heat Pump) replaced our natural gas furnace and main air conditioner. It services the basement through to the second floor. The equipment is designed to efficiently heat the house in temperatures as low as -30 C. In extremely cold conditions, a duct-based auxiliary electric heater automatically engages (Mitsubishi Electric SVZ Series 10KW Auxiliary Heater).

A small ductless air-source heat pump (Mitsubishi Electric MSZ Series Ductless Cold Climate Hyper-Heat Pump) replaced our ductless air conditioner. It services the partial third floor. The electric baseboard heaters now serve as an auxiliary heat source, when needed.

A hybrid-electric water heater (Rheem Professional Prestige Pro Terra Hybrid-Electric Heat Pump) replaced our gas water heater. It extracts the ambient heat from the air throughout the mechanical room to heat water.

The natural gas line remains only to serve our existing oven/stove. Once it is replaced with an induction-based system, the gas line will be ripped out and capped at the meter.

G&M: What needed to be done to the home in order to install this device?

Scorgie: Prior to installation, we retained a mechanical designer to prepare a set of drawings and undertake modelling. This was necessary to appropriately size and configure the equipment. It also served as the basis of the mechanical permit application, and informed the installation process. We then retained an electrician to upgrade our electrical panel, meter and conduit connection to support 200 amperage service and secured an electrical permit. This was necessary to accommodate the new mechanical equipment, in addition to a planned induction stove and level 2 EV charging station. Finally, we removed all existing mechanical equipment.

After installation, the electrician installed high voltage breakers and cable connections to supply electricity to the new mechanical equipment, and a plumber connected the water heater.

G&M: All in, what would you say was the cost of this retrofit, and did you get any grants to offset it?

Scorgie: The total cost of all mechanical and associated improvements, exclusive of HST, was approximately $43,200. This includes mechanical drawings ($1,200), mechanical equipment and installation ($33,500) and electrical and plumbing work ($8,500). Specifically, the cost of the mechanical equipment and installation includes a large central duct-based air-source heat pump ($15,500), auxiliary electric heater ($1,200), small ductless air source heat pump ($6,000), custom duct work ($5,500) and labour ($1,100).

While we have not yet submitted an application through the Canada Greener Homes Grant, we anticipate the hybrid-electric water heater will be the only qualifying improvement. While the large central duct-based air-source heat pump originally qualified, it was removed from the program over the summer. To the best of our understanding, this was due to revised criteria, which the outdoor compressor fell marginally short of achieving. This is ironic, as we selected the unit largely due to its reputation as the solution most capable of providing sufficient thermal comfort throughout Canadian winters. The performance of Mitsubishi Electric is unparalleled in this respect. It is also unfortunate, because air-source heat pumps are among the lowest-hanging fruit in mitigating the impacts of climate change in Canada. We view this as a failure of leadership by the federal government.

G&M: Even though it’s still new, do you have a sense of what your ROI will be?

Scorgie: The capital costs of air-source heat pumps are marginally higher than their natural gas counterparts, and the equipment is comparable in terms of anticipated lifespan. However, the efficiency of air-source heat pumps is significantly higher, and the cost of natural gas is increasing. As a result, we anticipate marginally lower operational costs to heat the house in colder months. Conversely, air-source heat pumps operate on the same principle as conventional air conditioning units. Because of this, we do not anticipate comparable savings to cool the house in warmer months. With respect to the hybrid-electric water heater, we anticipate the unit will pay for itself over the course of its functional life.

G&M: What advice would you have for other homeowners trying to reduce their domestic gas?

Scorgie: Go electric with heat pump technology. We have the solutions, and it is time to implement them.

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