Whole-Home Air Filtration: How Smart Filtration Works

Last year, Woosh was featured in Wirecutter’s “The Best Air Purifier” under a new section for Whole-home purification options (2 min read) and it reminded me that while we’ve talked a lot about our smart filter, we haven’t spent enough time on the other half of the equation: air quality monitoring.

Today, I want to show you exactly how monitoring and automation come together to make filtration smarter and why that matters.

Traditional Filtration

Furnace and AC filters were originally designed to protect equipment, not people. As the industry evolved, those same filters began serving a dual purpose, helping improve indoor air quality.

But here’s the catch:

• • Higher-efficiency filters must be carefully matched to the system to avoid restricting airflow.
  • Most HVAC systems only filter when heating or cooling is running—or if you’ve set a fixed fan schedule (like 10 minutes every hour).

Even with a good filter, this means poor air quality can linger for hours before anything happens.

Smart Filtration, Explained

Smart filtration transforms your HVAC into a whole-home air purifier that automatically responds to poor air quality, instead of just during heating/cooling or fan timers.

It works because of three key components:

1. 1. Air Quality Monitoring – Detects spikes in PM2.5 and other pollutants in real time.
   2. Smart Thermostat Integration – Turns on the fan when air quality drops, even if you’re not heating or cooling.
   3. High-Efficiency Filter with Performance Monitoring – Captures pollutants effectively and alerts you when the filter needs replacing.

When poor air quality is detected by the air quality monitor, a signal is sent to the smart thermostat to start fan-only circulation and filter the air. Once air quality returns to normal another signal is sent to stop the fan.

Diagram of smart filtration flow

Without Smart Filtration

When nothing intervenes, pollutants can linger—especially in newer, airtight homes. We call this dwell time, and it’s not unusual for it to last 10+ hours especially newer homes which are optimized for energy efficiency thus air tight. That’s several hours of breathing unhealthy air.

Extended poor air quality without intervention. Before smart thermostat integration

With Smart Filtration

When Woosh detects a spike, it kicks the fan on immediately and starts cleaning the air.
The spike drops quicker—often within 30 minutes to a couple hours —which can reduce your exposure without having to lift a finger.

Shortened poor air quality with intervention. After smart thermostat integration

How do I set this up?

You don’t need a single all-in-one product to enable smart filtration—many homes already have some of the pieces in place:

Air Quality Monitoring – Many indoor air quality monitors (AQMs) can track PM2.5 and other pollutants. Check your product guide or mobile app to see if it supports fan control or automation features.

Smart Thermostat Integration – Many smart thermostats can be configured to run your HVAC fan when air quality drops, even outside of heating or cooling cycles. Look for “indoor air quality,” “ventilation,” or “fan automation” settings.

High-Efficiency Filter – The filter doesn’t need to be “smart,” but it should be high efficiency and compatible with your HVAC system’s airflow limits. Since it’s hard to tell when a filter is actually full, use reminders and choose a filter with low pressure drop for optimal performance. Filtrete and Woosh both offer filters with some of the lowest pressure drops in their class, making them ideal for most systems.

But if you want it all in one simple package, Woosh makes it easy—combining air quality monitoring, smart thermostat integration, and high-performance filtration into a single solution that works automatically, right out of the box.