Residential Stationary Combustion Sources: Emissions Calculations

The quality-of-fit of this data to the National Inventory Report target is the best one so far in PlanZero. I wonder if the small remaining discrepancy is related to wood combustion because accounting for firewood across Forest, Harvested Wood Products, and residential heating is tricky. This can't be the only explanation though, because firewood accounts for a steady 3-4% of residential emissions over the last 10 years, while the the discrepancy drops to almost zero by 2023. I don't know what else might account for the discrepancy.

Critical Success Factors

To reduce residential stationary combustion emissions, it seems required to do some combination of the following:

• Reduce the number of residences relying on combustion for space heating, water heating, and cooking.
• Increase the thermal insulation of combustion-heated spaces.
• Increase the use of renewable fuels in equipment designed for fossil fuels.
• Reduce the unnecessary heating of e.g. vacant rooms.
• Reduce the temperature Canadians expect in their homes on cold days.
• Reduce the average size of residences.

Barriers

It must be stated that the over-arching strategy for emission reductions in this sector is the greater use of heat pumps. That said, it is challenging to make progress on the critical success factors above for several reasons:

• Upfront Cost, Long ROI: upgrading a building to be more energy-efficient or to use a different heating technology can save money over time, but upgrades require cash up front. The payback period for home upgrades is typically many years.
• Confusion About Heat Pumps: Heat pumps are a new technology compared to e.g. oil furnaces. Natural Resources Canada has developed a mini-site about heat pump technologies, explaining e.g. the basics, and addressing myths.
• Distributed Decision-Making: residential heating technology is controlled by the buying decisions of the general Canadian public. Convincing homeowners to take action takes time. (This barrier has a positive flip-side, that there can be early adoption as soon as any homeowners are ready to try new technology.)
• Switching Takes Planning: upgrades to owner-managed residences are more-frequently motivated by the failure of a home element, as compared with professionally managed buildings. After failure, there may be time pressure, cashflow pressure, and fewer options than for a planned upgrade. Switching to a ground-source heat pump requires some excavation. A rushed replacement of an oil-burning furnace may regretably lock in decades of future emissions, which could have been avoided by a planned heat pump upgrade. (Statistics Canada's 2025/2026 Households and the Environment Survey (HES) specifically added questions to track "Planned" vs "Emergency" replacements to better understand this behavior.)
• Desire for Warmth: people like to be warm and cozy in winter, it's unpleasant to be cold in one's own home.
• Desire for Space: People want more private space; Canada's average residential floor space per household has been rising for decades, it appears to have reached 150 square metres (link).
• Personal Preference: some people just like cooking with gas.

Strategies

One technology strategy dominates the plan for this sector: deploy more heat pumps. Heat pumps have been known for hundreds of years, but the technology to provide practical HVAC systems has only been in production since the 1980s. They are now a good alternative to oil and gas heating: effective, practical, affordable. Indeed Canadians are switching to heat pump technology, and as they do so, direct emissions in this sector are dropping, and could continue to drop to near zero. Heat pump technology applies to both the heating of living spaces, and the heating of water, and can help decarbonize both emission sources.

There are a number of government programs in place to accelerate the adoption of heat pumps, such as through information campaigns and financial incentives. There are also incentive programs to support and encourage Canadians to make their houses more thermally efficient, which helps reduce energy waste regardless of which fuel is used to heat the home.

Conclusion

Despite it being so cold here, the IPCC category of residential stationary combustion sources only accounts for about 5% of national net emissions. Still it might be one of the easiest 5% of emissions to eliminate, because modern heat pumps are cleaner and more cost-effective than natural gas, and are effective down to temperatures of about -30C (enough for most of Canada's residences). I expect it's just a matter of time until Canada's housing stock is converted to use heat pump technology, and emissions in this sector drop to zero. Still, it will be difficult to reach zero emissions in this sector by 2050 without a strong government push, as gas furnaces are still being installed today, and today's new gas furnace may still be running in 2050.

This post has introduced a relatively accurate estimator of residential stationary combustion sources based on data from Natural Resources Canada's National Energy Use Database. The IPCC / Stationary Combustion / Residential page has been refreshed to feature this estimator, as well as updated critical success factors, barriers to those success factors, and strategies to address those factors and barriers. The next post in this series replicating the NIR will look at another more familiar source of emissions to the general public: gasoline-burning vehicles. The NIR reports the bulk of gasoline vehicle emissions via a pair of categories covering smaller vehicles (compacts, sedans and the like), and larger vehicles (SUVs and light-duty trucks), but I expect the research on both to be similar, as well as the critical success factors, barriers, and strategies (e.g. use EVs instead).

Until then,

- James Bergstra