As of August 6, 2026, Environment Canada has issued an air quality warning for Metro Vancouver and the Fraser Valley due to wildfire smoke drifting in from fires burning across BC. At the same time, a heat dome is pushing daytime highs to 32°C and above across the Lower Mainland — with temperatures feeling closer to 35–38°C with the humidex.
This combination — extreme heat plus poor outdoor air quality — creates a specific challenge for homeowners: you need to cool your home, but you can't just open the windows. This guide covers exactly what to do with your HVAC system, HRV, and air filters right now to stay cool and breathe clean.
Should You Run Your HRV During Wildfire Smoke?
This is the most common question we're getting from customers right now, and the answer is: no — turn your HRV to recirculation mode or shut it off.
An HRV (Heat Recovery Ventilator) is designed to bring fresh outdoor air into your home. That's exactly what you don't want during a smoke event. Most HRV factory filters are not HEPA-rated and will not capture the fine particulate matter (PM2.5) in wildfire smoke.
What to do with your HRV right now:
- Switch to recirculation mode if your unit has it — this circulates indoor air without bringing in outdoor air
- If your HRV doesn't have a recirculation mode, turn it off entirely until the air quality warning is lifted
- Check your HRV filter — if it's been more than 6 months since it was cleaned or replaced, now is the time
- After the smoke clears, run your HRV on high for several hours to flush out any smoke that entered before you switched modes
What MERV Filter Do You Need for Wildfire Smoke?
Standard furnace filters (MERV 1–7) do very little against the fine particles in wildfire smoke. To meaningfully filter PM2.5 particles, you need MERV 13 or higher.
Here's the breakdown:
- MERV 1–7: Captures large dust and pollen — does almost nothing for wildfire smoke particles
- MERV 8–12: Better, but still misses most fine particulate matter from smoke
- MERV 13–16: Captures fine particles including PM2.5 — the standard recommended for smoke events
- HEPA (MERV 17+): Hospital-grade filtration — the gold standard for air quality
Important: if you upgrade to a MERV 13+ filter, check that your HVAC system can handle the increased airflow restriction. A filter that's too dense for your system can reduce airflow, cause the system to work harder, and potentially damage your equipment. Grove Mechanical can assess your system and recommend the right filter for your setup.
During the current smoke event, check your filter every 2–3 days — smoke particles clog filters much faster than normal dust.
How to Keep Your House Cool Without Opening Windows
Opening windows is the instinct when it's hot — but with smoke in the air, that brings PM2.5 directly into your home. Here's how to stay cool with windows closed:
- Run your AC or heat pump on cooling mode — this is exactly what it's designed for. Keep your thermostat set to 24–26°C to balance comfort and efficiency
- Close blinds and curtains on south and west-facing windows during the afternoon — this alone can reduce indoor temperatures by 3–5°C
- Use ceiling fans counterclockwise (summer mode) to create a wind-chill effect — this makes 26°C feel like 23°C
- Avoid using the oven or stove during peak heat hours (12pm–6pm) — use a microwave, BBQ outside, or eat cold foods
- Create a "cool room" — close off one room with good AC coverage and use it as a refuge during the hottest part of the day
Should You Run Your AC When There's Smoke Outside?
Yes — with one important condition: make sure your AC system is set to recirculate indoor air, not bring in fresh air from outside.
Most central AC systems and heat pumps recirculate indoor air by default — they cool the air already inside your home. This is fine during a smoke event. However, some systems have a "fresh air intake" damper that can be manually opened or closed. If yours has one, make sure it's closed.
Ductless mini-splits (the wall-mounted units) recirculate indoor air entirely and are an excellent option during smoke events — they cool effectively without any outdoor air exchange.
Do You Need an Air Purifier? What to Look For
If you don't have central AC with a MERV 13+ filter, a portable HEPA air purifier is your best option for improving indoor air quality during a smoke event. Here's what to look for:
- True HEPA certification — not "HEPA-type" or "HEPA-like" — only True HEPA captures 99.97% of particles 0.3 microns and larger
- CADR rating appropriate for your room size — CADR (Clean Air Delivery Rate) of at least 200 for a standard bedroom, 400+ for a living room
- Activated carbon filter — helps with smoke odour in addition to particles
The BC Lung Association recommends running a HEPA purifier in the room where you spend the most time. If you're building a DIY version, a box fan with a MERV 13 filter taped to the intake side works reasonably well as a temporary measure.
Health Risks: Who Is Most Vulnerable Right Now
The current combination of extreme heat and poor air quality is especially dangerous for:
- Adults over 65 and children under 5
- Anyone with asthma, COPD, heart disease, or other respiratory or cardiovascular conditions
- Pregnant women
- People working outdoors
Symptoms of smoke inhalation include irritated eyes, nose and throat, coughing, shortness of breath, and headaches. If you experience chest pain, difficulty breathing, or feel faint, seek medical attention immediately.
Metro Vancouver's Air Quality Health Index (AQHI) is updated hourly at metrovancouver.org. Check it before opening windows or spending time outdoors.
Long-Term Solution: What to Install Before Next Summer
If this heat wave has made you realize your home isn't equipped to handle BC summers, here are the most effective long-term solutions:
- Review the active provider requirements for the project before relying on an amount or combination rule.
- Ductless mini-split: If your home doesn't have ductwork, a ductless system is the fastest and most cost-effective way to add cooling. Ideal for strata units and older Vancouver homes. Quilt-certified systems are available for strata buildings with strict installation requirements.
- Whole-home air purification: Systems like the Lennox PureAir or Aprilaire 5000 integrate directly into your existing HVAC system and provide MERV 16 filtration throughout your entire home — not just one room.
- HRV upgrade: If your HRV is more than 10 years old, upgrading to a newer unit with better filtration and smarter controls can significantly improve indoor air quality during both smoke events and normal operation.
Grove Mechanical's Response to the Current Heat Wave
We currently have openings this week for AC installations and heat pump installs across the Lower Mainland. If your home doesn't have cooling and you're struggling through this heat wave, call us at 604-371-4949 — we can often have a ductless mini-split installed within 3–5 business days.
We're also available for emergency service calls if your existing AC or heat pump has stopped working during the heat. Our team serves Vancouver, Surrey, Langley, Burnaby, Richmond, Coquitlam, Abbotsford, Chilliwack, and all surrounding communities.
Frequently Asked Questions
Is it safe to run my AC during a wildfire smoke event?
Yes. Central AC and heat pumps recirculate indoor air and do not bring in outdoor air during normal operation. Running your AC during a smoke event is safe and actually helps by keeping windows closed and filtering indoor air through your furnace filter. Make sure your filter is a MERV 13 or higher for best results during smoke events.
Should I turn off my HRV when there is wildfire smoke?
Yes. Switch your HRV to recirculation mode or turn it off entirely during air quality warnings. HRV systems are designed to bring in fresh outdoor air, which is counterproductive during smoke events. Most factory HRV filters do not capture PM2.5 particles from wildfire smoke. Turn the HRV back on and run it on high for a few hours once the air quality warning is lifted.
What MERV filter should I use during wildfire smoke?
MERV 13 is the minimum recommended for meaningful protection against wildfire smoke particles (PM2.5). MERV 16 provides better filtration. Check that your HVAC system can handle the increased static pressure before upgrading — some older systems may need a professional assessment. During a smoke event, check and replace your filter every 2–3 days as smoke particles clog filters much faster than normal dust.
How hot is it going to get in the Lower Mainland this week?
As of August 6, 2026, daytime highs are forecast at 30–33°C across Metro Vancouver and the Fraser Valley, with humidex values making it feel like 35–38°C. Temperatures are expected to remain elevated through the end of the week. Environment Canada has issued heat warnings for the region. Check Environment Canada's weather forecast for your specific municipality for the latest updates.
What is the air quality like in Vancouver right now?
As of August 6, 2026, Environment Canada has issued an air quality warning for Metro Vancouver and the Fraser Valley due to wildfire smoke. Fine particulate matter (PM2.5) levels are elevated. The Metro Vancouver Air Quality Health Index (AQHI) is updated hourly at metrovancouver.org. Limit outdoor activity, keep windows closed, and use a HEPA air purifier or MERV 13+ furnace filter indoors.
Can Grove Mechanical install AC this week during the heat wave?
Yes — we currently have openings for ductless mini-split and heat pump installations this week across the Lower Mainland. A ductless mini-split can typically be installed in one day. Call 604-371-4949 or book online for a same-day or next-day assessment. We serve Vancouver, Surrey, Langley, Burnaby, Richmond, Coquitlam, Abbotsford, and all surrounding areas.
What is the difference between a heat pump and an air conditioner for cooling?
Current-program note: rebate rules, funding, equipment, application sequence and payment timing change. Do not rely on historic rebate amounts, stacking examples, invoice calculations or eligibility examples in this article. Review the active provider terms and request a free rebate-ready estimate for a current home-specific discussion.