Heat Pump Proves to Be Economical Climate Remedy, Even in Ottawa

Our new air-source heat pump being installed in February 2017.

Back when our environmentally-conscious friends were lining up to buy Toyota Priuses and Teslas, Lenore and I went down a different path. To do our part in the fight against climate change we decided to replace our gas furnace with an electric heat pump. With this single action we reduced the greenhouse gas emissions from our home by an astounding 90 percent. And, contrary to everything we were told, switching to electric heat in Ottawa has not increased our monthly costs.

We decided to get rid of our gas furnace after first calculating our carbon footprint. A carbon footprint relates the things we do and the things we buy to the resulting emissions of climate-warming greenhouse gases. For the most part, these emissions are the result of burning fossil fuels — coal, oil, propane, and natural gas. Reducing our carbon footprint is the most effective way that we can combat climate change. Ultimately, the goal is to eliminate using fossil fuels entirely.

Fossil fuels are used in just about everything we consume and everything we do. That’s what makes combating climate change so difficult. I used an online tool to calculate the carbon footprint for our two-person household in 2016.

Carbon footprint in 2016 for our two-person household in a 1300 square foot semi-attached house heated with natural gas in Ottawa, Canada. Emissions of greenhouse gases are expressed as an equivalent amount of carbon dioxide.

At 21 metric tons of carbon dioxide per year for a two-person household, our carbon was about 30 percent lower than average for Canada. This reflects our lower-than-average energy use, because our house is smaller than most and we don’t use our car every day.

The largest portion of our carbon footprint, about 15 metric tons per year, is from fossil fuel use that is embedded in the food we eat and the stuff that we buy. This is also the hardest part of our carbon footprint to manage. These emissions are the result of decisions by other people who we rely on indirectly to produce stuff and deliver it to stores, where we buy it. It is nearly impossible for us to know the lowest-carbon options for stuff we need to buy.

The remaining 30 percent of our carbon footprint is easier to manage because it relates more directly to decisions that Lenore and I make about travel and how we use energy in our home. In 2016, home energy use accounted about 18 percent of our total carbon footprint. So, we decided that our first move would be to reduce these emissions.

In Canada, buildings account for about 23 percent of annual greenhouse gas emissions. Heating is the largest source of emissions from homes. For most people in Ottawa this means burning natural gas in furnaces. Burning natural gas is convenient source of heat, but it’s bad for emissions.

One strategy for reducing these emissions is to make our home more energy-efficient. However, we learned that affordable measures to make our 1920's house more efficient would not take us very far toward the ultimate goal of completely eliminating the use of fossil fuels.

We also learned that we could have a far greater impact on our carbon footprint by changing the type of energy we use. In Canada, 82 percent of electricity is produced from sources that do not involve burning fossil fuels, such as hydroelectricity, nuclear power, wind and solar. So, we decided to switch from natural gas to electric heat when the opportunity arose.

We were spurred into action on the fateful day of Friday, January 13, 2017. It was the coldest day of the year and the day for the annual checkup of our heating system. We were getting dinner ready when the service technician called me to the basement to show me a crack in the heat exchanger. He was “red tagging” the furnace and disconnecting it. The furnace had to be replaced, immediately.

No sooner had the technician packed up and was out the door when the phone rang. It was a salesman from the heating service company. Did we want to buy or rent our new gas furnace? When Lenore replied that we had decided to switch to electric heat, the salesman laughed derisively.

While not particularly effective as a marketing ploy, the salesman’s reaction was understandable. Conventional wisdom is that heating with natural gas is by far the less expensive option. Everyone in Ontario knows that you’d have to be crazy to switch from gas to electric heat. A few months earlier, in 2016, an article in the Toronto Sun reported that switching from gas to electric heat would cost an Ontario homeowner over $2000 per year in higher heating costs.

Heat pumps use a little electric energy to move a larger amount of heat energy from the outside air to heat the air inside a home.

That might have been our fate if we had installed conventional electric heat. However, we went the unconventional route and installed an air-source heat pump, which uses only a fraction of the amount of electricity required by a conventional electric heating system.

The way a heat pump works is fundamentally different from a conventional electric heating system. In conventional electric heating, the electricity is converted directly into heat inside the home, with an efficiency of around 100 percent. An air-source heat pump heats works indirectly by using a small amount of electricity to absorb a larger amount of thermal energy from the outside air and move it inside. As a result, a heat pump can deliver an efficiency of around 300 percent.

We could not foresee exactly how things would work out when we launched this project. The furnace salesman was not the only skeptic we encountered. We were confident that converting to electric heat would reduce our carbon footprint. And, we hoped that installing a heat pump would not be too much trouble, and it would keep costs down. But, we could not be certain.

Replacing our gas furnace with an electric heat pump reduced the carbon footprint of our home by 90 percent without affecting total energy costs.

The cost of heating with the heat pump has worked out better than expected. In 2018, the first full year of using the heat pump, the total amount we paid for natural gas and electricity was the same we were paying previously when heating with a high-efficiency natural gas furnace.

It took a over a month to install the heat pump. Most of this time was spent waiting for Hydro Ottawa, the local electric utility, to upgrade our electrical service. We needed to upgrade our electric meter to 200 amps so that we have enough electricity to run the heat pump now and to add an electric car charger later.

The heat pump fit directly into the space left when the gas furnace was removed, and it uses the same duct work as the old furnace. All the contractors we consulted recommended using the Mitsubishi ZUBA air-source heat pump. The ZUBA is designed specifically for a cold climate such as we have in Ottawa, and it is capable of keeping the house warm until outdoor temperatures drop below about -15 degrees Celsius. At colder temperatures, a conventional electric heater works in tandem with the heat pump.

Our total cost was about $20,000. This included the purchase and installation of the heat pump and the electric backup heater, upgrading our electric service, and additional heavy-duty wiring inside the house. Therefore, we have payed about $15,000 more than we would have for a new gas furnace. This amount is comparable to the premium that we could expect to pay for a new high-efficiency hybrid or an electric car.

The upside is that we have achieved a 90 percent reduction in emissions from home energy use. And, this shrank our carbon footprint by twice as much as we could have done by buying a Tesla. The downside is that we do not have a flashy new car sitting in our driveway. Also, unlike electric cars, no one is giving out rebates to offset the cost of installing heat pumps to convert from natural gas to electric heat, at least not yet.

Our heat pump is not going to save the world, but it is a start toward us doing our part. The United Nations climate panel has called for cutting the use of fossil fuels 50 percent by 2030. This is an immense challenge. Our experience shows that taking a first step is not difficult, but you have to be open to the possibility of making different choices.

Navigating a changing environment — hydrologist, engineer, advocate for renewable energy, currently writing about the personal side of technological progress