Heat Vulnerability Index (HVI)
Peel Public Health's overall heat-risk score for a census tract, grouped into quintiles: 1 is the lowest fifth, 5 the most vulnerable fifth.
Method
A score you can audit in under 20 seconds.
Sanctuary starts with the Peel HVI, then weighs modelled reach, trust, roof class, and facility fit. The five-factor score is heat-led: flood and winter / energy burden are shown alongside each building as extra lenses, not folded into the rank yet. It ranks where to investigate first, and does not certify that any named building is ready or equipped.
How it works
Five weights answer one decision.
If Peel can harden only five trusted buildings first, Sanctuary ranks which sites to investigate. The score is a planning screen, not an engineering study.
Exposure
How much heat stress the area faces.
Sensitivity
How strongly heat affects the people who live there.
Adaptive capacity
How easily people can cool down, move, communicate, or get help.
FactorWeightEvidenceWhat it measures
Heat vulnerability nearby35%verifiedThe Peel HVI quintile at the building's census tract, checked against Peel's public feature service.
Vulnerable population in catchment25%modelledA modelled 500 m catchment stands in until a real walkshed (the true area reachable on foot) is run. The head count stays pending.
Trust / community role20%verifiedA public-facing civic or faith and community role, backed by the building's own official page.
Rooftop hardening potential10%modelledA small, medium, or large planning class read from the visible roof footprint. Not a solar design.
Facility suitability10%modelledA first-pass fit for a public heat or outage site. Final readiness needs a site audit.
Where the weights come from
The five weights are our judgment, not a published formula. We structured them on two sources already cited here: Peel's own Heat Vulnerability Index, which splits heat risk into exposure, sensitivity, and adaptive capacity, and the USDN resilience-hub functions. Heat leads at 35 percent because it is the only axis that is fully verified and resolved tract by tract. The other four are planning proxies that a site audit later replaces.
What a site audit verifies
- Roof structural load and condition, before any rooftop equipment.
- Backup power and electrical readiness, confirmed with the operator.
- Accessibility and step-free access, into and through the building.
- Operating hours and staffing during an actual activation.
Backup power is the energy anchor. A hub with solar and a battery is a distributed energy resource: on a normal day it can support the local grid, and during an outage it islands to keep cooling, charging, and information running. That is the kind of resilience Alectra Utilities plans for in its distribution-system plan, not a claim that any of these buildings runs it today.
Why winter maps energy burden, not temperature
The winter layer on the map is real, but it deliberately maps energy burden, not temperature. Here is why. Heat vulnerability varies block by block because of the urban heat island, so the HVI resolves it tract by tract. Winter cold has no equivalent gradient, there is no winter heat-island, so a per-tract cold-temperature index would invent an exposure axis that is not real. Winter resilience need is driven instead by energy affordability and marginalization: who can least afford to heat a home, and who is most isolated in a cold snap. That is real per-area data, so the winter layer maps the 2021 Ontario Marginalization Index Material Resources dimension, labelled modelled, and keeps heat as the lead, verified hazard.
Real vs estimated
The labels are part of the product.
You can trust this because it never hides what it does not know. Every value on screen is verified, modelled, or pending, and says which.
Verified
The HVI layer, building names, addresses, source links, and every HVI quintile, all checked against the public Peel feature service.
Modelled
The 500 m reach, the roof and hardening class, and the first-pass score. Useful for triage, not for investment decisions.
Pending
Backup power, cooling capacity, electrical readiness, owner agreement, and solar or battery sizing. None of it is assumed. All of it is flagged for a site audit.
If Sanctuary had existed
Two real events. One pre-verify list.
A heat warning at Pearson last June, five kilometres from Malton. An Ottawa derecho three years earlier. Both are real, both are sourced. What Sanctuary would have changed is the planning artifact, a ranked five-building list that already existed before the morning of the event, not the event response itself.
Planning counterfactual, not measured impactThese are real events with public sources. The 'if Sanctuary had existed' framing is a planning thought experiment, not a claim about lives saved, costs avoided, or outcomes achieved. The honest contribution is the pre-verify list: knowing which trusted buildings to investigate first, before the next heat day or outage.
Dossier · 01 A 35.8 °C day at Pearson, about 5 km from Malton.
What happened. Environment Canada issued a heat warning across the Greater Toronto Area. Pearson reached 35.8 °C, and the humidex pushed higher. Cooling and respite fell to whichever public building happened to be open. Peel does not run designated seasonal cooling centres, so public facilities serve as informal cooling during their regular hours.
If Sanctuary had existed. If Sanctuary had been in place before that morning, planners would already hold a five-building pre-verify list, Malton Community Centre and Library at rank #1. It flags which trusted buildings inside the hottest HVI pocket to check first for opening hours, communications, and refuge readiness. Not new buildings. The same buildings, made stronger.
Dossier · 02 The May 2022 derecho hit Ottawa, not Peel.
What happened. A derecho, a fast-moving wall of straight-line winds, cut power to much of eastern Ontario. Ottawa opened community and recreation facilities as reception points for charging, respite, showers, and information. The event happened elsewhere, but the pattern is one Peel would inherit during the next storm or grid stress: public buildings becoming emergency infrastructure on short notice.
If Sanctuary had existed. If Sanctuary's ranking had existed across Alectra's territory before May 2022, the question 'which civic buildings should we prepare and communicate about first?' would already have had a defensible answer. The artifact is the ranked list, not the event response.
Evidence
Public buildings already become emergency infrastructure.
Peel has a local shelter-access gap. Ontario storms show recreation centres and community buildings becoming charging, shower, warmth, and information points. Sanctuary does not claim they are ready today. It ranks what to verify first.
Peel-local gap
Local reporting says Peel and Mississauga do not run designated seasonal warming centres. Public facilities stay open during their regular hours instead. Caledon has opened recreation and community buildings as warming and charging stations during outages and cold snaps. Sanctuary's cautious claim: pre-rank which trusted buildings to verify first.
Mississauga.com · warming centres in PeelOntario outage precedent
After the May 2022 derecho, Ottawa opened community and recreation facilities as reception points for charging, respite, showers, and information. If Sanctuary had existed before the event, planners could have pre-ranked which trusted buildings to prepare, communicate, and verify first.
Ottawa Citizen · May 2022 storm recoveryBrampton Lighthouse Project
A federal case study names 79 registered places of worship citywide, 39 of them with signed partner agreements. Together they form an emergency-refuge network for heat, storms, and floods. It is a trust network, not a solar program. Sanctuary's contribution is adding solar and battery so a refuge keeps power.
Canada in a Changing ClimateUSDN resilience hubs
The Urban Sustainability Directors Network frames a resilience hub around five functions: power, communications, facilities, operations, and services. Sanctuary borrows that vocabulary rather than inventing a definition.
USDN Resilience Hubs (2018)Faith buildings already run on solar
Faith & Common Good counts 137 Ontario faith institutions using solar. Gurdwaras, mosques, mandirs, and churches are realistic solar adopters, not a hypothetical.
Faith & Common GoodFunding a tax-exempt hub
A library, municipal centre, or place of worship can claim the 15% refundable Clean Electricity Investment Tax Credit (CEITC), the federal credit written to include tax-exempt owners. The 30% Clean Technology Investment Tax Credit excludes them, so it is not the lever for these buildings.
Canada Revenue Agency · Clean Electricity ITC