This is the first part of a two-part column.
Heat pumps are having a moment here in the Yukon.
A few years ago, bringing up heat pumps at a party was a good way to end up alone in the corner talking thermodynamics with the only engineer at the shindig. Now, you’re likely to hear people comparing their neighbour’s experience with what they heard about heat pumps on Whitehorse breakfast radio.
But should you get one? Are they an expensively ineffective novelty gadget for climate enthusiasts? Or will they liberate you from carbon emissions, heating oil bills and your insurance company’s whinging about your oil tank?
The heat pump concept is brilliant in its simplicity: take your refrigerator and turn it inside out. Instead of taking heat out of beer inside the fridge and moving it to the lint-covered coils on the back, you take heat out of the air in your backyard and move it into your house.
This is what allows heat pumps to claim efficiency ratios that seem like science fiction. Energy Star Canada, a government program, reports that at a temperature of -8C an air-source heat pump – the kind with no expensive underground or underwater pipes that you might put in a typical Yukon home – can have a Coefficient of Performance (COP) of up to 3.7.
A COP of 3.7 means that for every unit of energy you put into your heat pump, it produces 3.7 units inside your house. That seems to violate the laws of physics. Unless your oil furnace was installed by Harry Potter, it can never produce more heat than you put into it as fuel.
But heat pumps are different because they are not “making” heat, but just “moving” it from your backyard into the house.
So, should you retire the fossil-fueled beast in your basement and replace it with a heat pump?
A lot of climate policy experts hope you will. The International Energy Agency (IEA) says that already more people around the world heat their homes with heat pumps than with that longtime Yukon favourite, fuel oil. Heat pumps already provide ten percent of global space heating needs. The IEA says over 60 per cent of buildings in Norway have heat pumps, as do over 40 per cent in Finland and Sweden.
An IEA scenario shows that if heat pumps raise their share of space heating from 10 per cent to 20 per cent, global natural gas use will fall by 80 billion cubic metres and oil by one million barrels per day.
Here in the Yukon, the government’s Our Clean Future report says that 120 kilotonnes of carbon dioxide was emitted from heating buildings in 2020. That’s about a fifth of our non-mining emissions. Thousands of Yukon homes are still heated by oil and propane.
It is wonderful that so many Norwegians have heat pumps. But they have abundant cheap hydropower, which we don’t anymore, and live in a somewhat warmer climate thanks to the Gulf Stream and their coastal location. Do heat pumps make sense for us too?
The first question is whether they work in the Yukon. The answer is yes. The number of users grows each year. I spoke to a Takhini resident, whom I am leaving anonymous so they don’t get pestered by too many heat-pump aficionados, who installed an air-source heat pump in 2021. The home is an old government house, retrofitted with six inches of additional insulation and new windows in 2006.
This Yukoner chose a Mitsubishi Zuba Central heat pump. The “central” refers to how the unit replaces the existing fossil-fuel furnace, in this case an oil furnace connected to a forced air system. You can also get smaller and cheaper “single” units, also known as “ductless” or “mini-splits” for very small homes or as backup for another heat source.
The report from Takhini is that their home is still cozy, with “even and consistent heat” which is “generally quieter than our old oil furnace.”
You may be wondering why they felt so comfortable in their home when you heard that heat pumps don’t work on cold Yukon days. While the main part of the heat pump is indeed ineffective below -30°C, at that point an old-fashioned electric heat coil activates to heat the house. The coil works well. But since using the coil eliminates the high COP that is the attraction of heat pumps, it has cost implications (as we will discuss next week).
The second question is how much heat pumps fight climate change. In Norway, the answer is clear. A Norwegian stops burning oil in her house, and uses zero-emission hydropower for her heat pump. Emissions go to zero.
The Takhini house used 1,616 litres of home heating oil in the year before they got their heat pump, emitting around 4.3 tonnes of carbon dioxide. This year they will emit zero.
But, here in the Yukon, when you turn on your heat pump you may be just pushing down the gas pedal on our growing fleet of rental diesel engines in Yukon Energy’s parking lot. For example, as I write this on a Sunday morning at the strangely balmy temperature of 1C, Yukon Energy reports the Yukon grid is using 68 megawatts of power, but only 59 of this is hydro. The rest is either natural gas or diesel.
Spin doctors at the Yukon government keep trumpeting that over 90 per cent of Yukon electricity comes from renewables. Which sounds great. What they don’t tell you is that as recently as 2013 this was 99.5 per cent, or that the average doesn’t matter as much as the incremental. That is to say, even if the grid is 90 per cent renewables on average, if I turned on a new heat pump right now it would force Yukon Energy to burn even more fossil fuel. In effect, my new heat pump would be 100 per cent diesel powered.
There are a lot of energy losses in such a situation. For example, diesel engines waste a lot of energy as heat as they run. Unlike other places, Yukon Energy does not capture this heat to re-use heating nearby buildings. It is vented into the sky along with the carbon dioxide.
The US Energy Information Administration estimates that electrical generation from petroleum products has a fuel efficiency ratio of just 30 per cent. The University of Calgary’s Energy Education centre says a rough rule of thumb is that each kilowatt-hour of electricity produced requires around 0.4 litres of diesel fuel, and produces 2.6 kilograms of carbon dioxide.
Then there are some power losses in the electricity lines to your house.
I spoke to one Yukon heating expert who believes that a high-efficiency propane furnace is more climate friendly than a heat pump powered by diesel electricity. However, the IEA says that, in general global terms including warmer countries using coal-fired electricity, heat pumps can cut emissions versus fossil furnaces by over 20 per cent even on electrical grids that have a lot of fossil power.
Next week we’ll finish our look at the climate benefits before diving deep on what you really want to ask about: the business case for your house.
Keith Halliday is a Yukon economist, author of the Aurore of the Yukon youth adventure novels and co-host of the Klondike Gold Rush History podcast. He won the 2022 Canadian Community Newspaper Award for Outstanding Columnist.