Retrofitting homes in Ontario entails significant embodied emissions: new policies needed
Bibliographic record
Abstract
Emissions reduction policies and programs should consider both the operational emissions reduction from single family home retrofits and the embodied emissions of the retrofit materials. This is because it can take 0.9–10.1 years before the emissions savings from building envelope upgrades in a gas-heated home equal the embodied emissions from the materials used. The wide range reflects the range of embodied emissions for different insulation and window replacement options. Heat pumps also have significant embodied emissions from their manufacture and from refrigerant leaks, but it takes less than two and a half years of operations in Ontario to offset the emissions investment relative to heating with a gas furnace. We recommend that Canada accelerate the phase out of insulation materials with high embodied emissions and increase incentives for window replacements. Programs and policies should also consider the age of the home and the potential energy savings when recommending building envelope improvements to maximize the total emission reduction potential. Finally, heat pumps should be promoted in all homes where low carbon electricity is available because this is the simplest and most effective way to reduce carbon emissions, especially when embodied emissions are considered.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".