How air moves, filters, and refreshes inside a home.
Plain-language reference reading on airflow, filtration, and ventilation systems in Canadian houses and apartments.
Three foundations of healthy indoor air
Each topic stands on its own, and they connect: air has to move before a filter can clean it, and a filter only handles the air a ventilation system actually circulates.
Understanding home airflow
Why air moves between rooms, how the stack effect behaves in winter, and where stale pockets form.
Read article FiltrationAir filtration: MERV & HEPA
What furnace filter ratings mean, where HEPA fits, and the trade-off between filtration and airflow.
Read article VentilationHeat recovery ventilation
How HRVs bring in fresh air without throwing away heat — and why they are common in Canadian homes.
Read articleTight Canadian homes need deliberate ventilation
Modern Canadian houses are built to be airtight so they hold heat through long winters. That efficiency has a side effect: without a planned way to bring in outdoor air, moisture, cooking by-products, and everyday indoor pollutants build up.
This is the reasoning behind mechanical ventilation requirements in the National Building Code and the widespread use of heat recovery ventilators across the country. The articles here walk through the basics without assuming a technical background.
- AirtightnessLess heat loss, but also less natural air exchange.
- HumidityCold-weather condensation makes moisture control a year-round concern.
- VentilationMechanical systems replace the air that a sealed building no longer leaks.
Common terms, in one place
| Term | What it describes |
|---|---|
| Air exchange | Replacing indoor air with outdoor air over time. |
| MERV | A rating scale for how much fine particulate a filter captures. |
| HEPA | A high-efficiency particulate filter standard, usually in portable units. |
| HRV | Heat recovery ventilator: brings in fresh air while reclaiming heat. |
| Stack effect | Warm air rising and drawing cooler air in lower down. |
Questions or corrections
If you spot an error or want to suggest a topic, send a note using the form. This is a reference-reading site, not a service provider, so messages are reviewed when time allows.