HVAC — System Brief
HVAC is the system that manages indoor temperature, humidity, and air quality — nine components ranging from comfort-only (ceiling fans, thermostat) to health-and-safety (combustion heating, ventilation) to water-damage risk (condensate drain, humidifier). The single most important thing to get right across this whole system: never let a gas appliance go a year without a licensed gas fitter service — everything else is recoverable; CO from a cracked heat exchanger is not.
The rules that matter most (system-wide tripwires)
These are the highest-stakes items pulled from across all 9 component notes. Each one fires on a trigger — most healthy systems have nothing to do today.
- Gas smell or CO alarm → evacuate immediately. Do not investigate. Call FortisBC 1-800-663-9911 (gas) or 911 (CO). — heating-system (Home Systems)
- Flu-like symptoms (headache, nausea, dizziness) when heating is on → evacuate and call 911. A cracked heat exchanger is colourless and odourless; the CO detector is the only warning. — heating-system (Home Systems)
- Any gas appliance must be serviced annually by a TSBC-licensed gas fitter. A cracked heat exchanger produces CO silently — annual inspection is the only way to catch it. — heating-system (Home Systems)
- Strata owners cannot pull homeowner gas permits in BC. All gas work requires a licensed contractor to pull the TSBC permit. — heating-system (Home Systems)
- Heat pump + thermostat mismatch silently runs the expensive aux heat. Verify heat-pump compatibility before any thermostat purchase — a wrong thermostat runs electric-resistance strips at 2–3× the cost of the heat pump. — thermostat (Home Systems)
- Bathroom fan ducting into the attic is a BC Building Code violation and an active mould risk. Exhaust must terminate outdoors — fix it, not on the next inspection. — ventilation (Home Systems)
- HRV/ERV must run continuously. Turning it off violates BC Building Code ventilation requirements; running on low costs $3–10/month. — ventilation (Home Systems)
- Condensate overflow in a strata can trigger a 250,000+ deductible chargeback. A $0 vinegar flush every 3–6 months is the entire prevention. — condensate-drain (Home Systems)
- Ceiling fan on an unrated electrical box is a falling hazard. Confirm “Fan Rated” is stamped on the box before running any ceiling fan — strata units always require a licensed electrician for box work. — ceiling-fans (Home Systems)
- Ice on the AC indoor coil or refrigerant lines → shut the system off. Running through a freeze destroys the compressor — often more expensive than replacing the whole outdoor unit. — cooling-ac (Home Systems)
- Leaky ducts waste 20–30% of conditioned air; routine duct cleaning is oversold. Seal accessible joints with mastic or UL 181-listed foil tape — not cloth duct tape, which fails within years. — ducts (Home Systems)
- Neglected humidifier tank grows mould and aerosolizes it. A portable humidifier not cleaned every 3–7 days becomes a biofilm nebulizer. — humidifier-dehumidifier (Home Systems)
- Clogged HVAC filter is the first domino. A grey filter starves the system of airflow → frozen AC coil in summer → overheated heat exchanger in winter → the root cause of the most expensive common HVAC service calls. — hvac-filters (Home Systems)
Component-by-component
| Component | The one thing to watch | Owner vs pro |
|---|---|---|
| heating-system (Home Systems) | CO risk from aging gas furnace — annual service by a TSBC-licensed gas fitter; furnace ≥15 years → start planning replacement | Annual service: pro only (TSBC-licensed gas fitter). Filter check + visual walk-by: owner. Heat pump seasonal clear: owner. |
| cooling-ac (Home Systems) | Ice on coil or refrigerant lines = shut off immediately; refrigerant is certified-tech territory; condensate drain is the most common owner-preventable failure | Filter, outdoor coil rinse, condensate flush: owner. Refrigerant, electrical, annual tune-up: pro only (TQ Refrigeration Mechanic). |
| ventilation (Home Systems) | HRV filter cleaning every 3 months is the entire owner job; bathroom fan must exhaust to exterior, not attic | Filter wash, cap check, tissue test on bathroom fans: owner. Annual HRV core clean, new installs, duct rerouting: pro. |
| ducts (Home Systems) | Duct leakage wastes 20–30% of conditioned air; mastic or UL 181-listed foil tape only — cloth duct tape fails; routine cleaning is not recommended | Visible joint sealing + damper balancing: owner. Aeroseal, pressurisation testing, replacement: pro. |
| thermostat (Home Systems) | Heat pump compatibility (O/B wire, aux staging) is the most common trap; missing C-wire is the most common smart-thermostat install snag | Like-for-like low-voltage swap: owner. Heat-pump wiring, C-wire run, multi-stage config: HVAC tech. |
| hvac-filters (Home Systems) | Check monthly; replace when grey regardless of schedule; upgrade to MERV 13 during wildfire smoke season | Entirely owner. |
| ceiling-fans (Home Systems) | Fan-rated box is the one safety line; flip direction twice a year (counter-clockwise summer, clockwise low winter) | Blade cleaning, direction, balancing, capacitor swap: owner. New box, new wiring, permit work: licensed electrician. |
| condensate-drain (Home Systems) | Vinegar flush every 3–6 months prevents the clog-to-overflow chain; confirm a float safety switch exists and is wired before each cooling season | Vinegar flush, algae tablets, float switch test: owner. Persistent clogs, float switch install, pan replacement: HVAC tech. |
| humidifier-dehumidifier (Home Systems) | Keep RH 40–50%; window condensation = you’re over-humidifying; in coastal BC, dehumidification is usually the priority; portable tank must be cleaned every 3–7 days | Portable units: entirely owner. Whole-home install, solenoid diagnosis: HVAC tech. |
Recurring upkeep at a glance
Cross-reference with Maintenance Calendar (Home Systems) for the full schedule.
| Frequency | Task |
|---|---|
| Monthly | Check HVAC filter (replace if grey); visual smell/sound walk-by at furnace or heat pump; confirm bathroom fan moves air (tissue test); read hygrometer and confirm 40–50% RH |
| Every 1–3 months | Replace standard 1-inch HVAC filter (monthly with pets, renovation dust, or wildfire smoke) |
| Every 3–7 days (humidifier use) | Clean portable humidifier tank with white vinegar |
| Every 2 weeks (dehumidifier use) | Clean portable dehumidifier filter |
| Every 3 months | Clean HRV/ERV filters (wash, air-dry, reinstall) |
| Every 3–6 months | Flush condensate drain with vinegar; drop algae tablet in drain pan |
| Every 6 months | Inspect and clear exterior HRV vent caps; pour 2 L warm water into HRV/ERV drain pan to test flow |
| Spring and fall | Clear outdoor heat pump unit of debris; rinse outdoor AC condenser coil; flip ceiling fan direction; adjust duct dampers for the season; seasonal thermostat mode switch and schedule check |
| Annually — September/October | Licensed gas fitter service on any gas furnace or boiler; HVAC tech service on heat pump (book in summer to beat the fall rush) |
| Annually — April/May | AC/heat-pump professional tune-up; test float safety switch before cooling season |
| Annually | HRV professional core cleaning and airflow balancing; visual inspection of accessible duct joints + spot-seal any finds; tighten ceiling fan hardware + inspect canopy wiring; replace whole-home furnace humidifier water panel |
| Before wildfire smoke season | Upgrade to MERV 13 filter; check every 2 weeks during smoke events |
| At gas furnace 15 years | Shift from “maintain” to “plan proactive replacement” — get quotes before it fails |
Biggest-cost / irreversible decisions
These are the decisions that feed → finance-replacement-reserves (Home Systems) and warrant The Decision Lifecycle before committing.
- Furnace or heat pump replacement (18,000+) — irreversible and high-cost. 50% Rule applies (repair > 50% of replacement = replace). Gas-to-heat-pump is a one-way door: plan the rebate stack (BC Hydro up to 16,000; FortisBC dual-fuel $5,000) and confirm contractor HPCN registration before signing. Never decide under emergency pressure on a cold night. → heating-system (Home Systems)
- Full AC or heat-pump replacement (15,000+) — same thresholds; compressor failure on a unit over 10 years old almost always means replacement, not repair. → cooling-ac (Home Systems)
- Full HRV/ERV replacement or new installation (9,000 retrofit) — irreversible (integrated into ductwork) and >$500; earns the full Decision Lifecycle, though urgency only when the unit has failed or hit end of life (15–25 years). → ventilation (Home Systems)
- Full duct replacement (12,000+) — irreversible and high-cost; professional sealing (3,000 Standard scope) is the right first step; full replacement only when the layout is wrong or ducts are corroded throughout. → ducts (Home Systems)
- Condensate overflow water damage in strata — the liability decision (not the repair) crosses both thresholds: strata deductible chargeback under SPA s.158 runs 250,000+. The repair is low-cost and reversible; the insurance consequence is not. → condensate-drain (Home Systems)
- Whole-home humidifier or dehumidifier installation (3,500+) — whole-home humidifier is an irreversible in-duct fixture; cost typically exceeds $500 installed. → humidifier-dehumidifier (Home Systems)
Strata vs detached
All 9 HVAC components are profile: universal — both home types have them. The split governs who maintains and who is liable.
| Scope | Strata | Detached |
|---|---|---|
| In-suite furnace, heat pump, ductless mini-split | Owner — cannot pull homeowner gas permits; contractor must | Owner — may pull homeowner gas permit |
| Central building boiler or shared air handler | Strata corporation (SPA s.72) | Not applicable |
| In-suite HRV/ERV or bathroom fan | Owner (typical) — verify strata plan; some high-rise buildings have shared ventilation | Owner |
| Shared vertical exhaust duct shafts | Strata (common property) | Not applicable |
| In-unit branch ducts and registers | Owner (Standard Bylaw 2) | Owner |
| Trunk ducts through common property or shared shafts | Strata (SPA s.72) | Not applicable |
| In-suite thermostat (controls only your unit) | Owner — low-voltage swap is permit-exempt under BC Electrical Safety Regulation s.18(2) even in strata | Owner — same exemption |
| Cooling system outdoor unit on balcony or exterior wall | Requires written strata council approval before purchase; may need ¾-vote if significant change to building appearance (SPA s.71) | Owner installs with applicable permits |
| Ceiling fan unit | Owner | Owner |
| Fan-rated box, new wiring | Licensed electrician under TSBC permit; strata council approval if altering limited common property | Licensed electrician under TSBC permit |
| Condensate drain (in-unit) | Owner — overflow that damages common property or unit below triggers SPA s.158 deductible chargeback | Owner |
| Portable dehumidifier or humidifier | Owner — no approval needed | Owner |
| Whole-home furnace humidifier | Owner by default (Standard Bylaw 2); plumbing penetrations of common/limited common property may require Standard Bylaw 8 approval | Owner |
The SPA s.158 chargeback pattern runs through five of the nine components: condensate drain, humidifier solenoid, AC condensate overflow, HRV condensate backup, and any duct failure that causes water ingress to a shared ceiling. Documented regular maintenance — dated photos and service invoices — is the procedural defence.
What this brief is NOT
This brief is a rollup and prioritisation layer, not a substitute for the component notes. It does not carry:
- Full mechanism explanations (heat exchanger physics, refrigerant cycle, HRV heat-exchange core)
- Discrimination tables (what each warning sign means in detail)
- Step-by-step maintenance procedures with “Done when” and “Stop and call a pro if” gates
- Triangulated pricing with per-source footnotes
- Full strata bylaw section references and SPA citation chains
- Named-resource card templates for the vendor roster
For all of that, open the component note. All nine are indexed in → HVAC (Home Systems). For the full vault, → Home Systems KB MOC.