The everything monitor
Airthings View Plus
Radon, PM2.5, CO₂, humidity, VOCs, and pressure in one wall-mounted display — the single-device answer for a whole-home baseline.
Gear guide · Air · updated October 2, 2026
Indoor air quality monitors
You can't manage what you don't measure. A particle (PM2.5) reading tells you when wildfire smoke has made it indoors and whether the purifier is keeping up; CO₂ tells you whether the house is under-ventilated for the people in it — the same question the audit's ventilation assessment answers with instruments.
Not sure this category applies to your home? The 30-second screener flags it if so, and the mold & indoor air guide covers the testing side.
The CO₂ truth-teller
Aranet4 Home
The reference consumer CO₂ monitor — e-ink display, years on a battery, NDIR sensor. Under ~800 ppm your ventilation is keeping up; sustained higher numbers make the case for an HRV.
The budget particle counter
Amazon Smart Air Quality Monitor
PM2.5, VOC, humidity and temperature for the price of a dinner out — enough to see smoke infiltration and check purifier placement, minus the CO₂ sensor.
Before you buy
- On wildfire-smoke days, indoor PM2.5 below ~12 µg/m³ is the target — if the number climbs when the purifier is running, it's undersized or mis-placed.
- CO₂ is a proxy for ventilation, not a pollutant at household levels — it tells you when to ventilate and when an HRV would pay off.
- Humidity readings on these double as your mould early-warning: winter target roughly 30–50%.
Some links here are affiliate links — as an Amazon Associate, AuditYourHome earns from qualifying purchases, at no extra cost to you. Picks are chosen on merit; no manufacturer pays for placement, and prices shown are planning bands, not quotes.
Measure, then act
Gear works best inside a plan: the planner reads your home's era, heating, and symptoms, flags the tests that matter, and puts the right categories on your list.
Also in gear guides: Radon monitors & test kits · Air purifiers (HEPA) · Carbon monoxide alarms