Hecena — Indoor Air Quality at Home | hecena.com
An ordered procedure: what to observe and measure, with timing in minutes, before buying any device.
Step 1 (5 minutes): Walk the home and note visible conditions — window condensation, staining at wall-floor junctions, dust buildup on cold surfaces, any musty odor near floors. Write down which rooms show which signs; this narrows the pollutant class before you measure anything.
Step 2 (10 minutes): Check the CO alarm in the sleeping area. Press the test button, confirm the indicator light, and note the date of battery replacement. If the alarm has a peak-read display, record the highest value it has held. Compare against the WHO windows: 10 mg/m³ over 8 hours, 35 mg/m³ over one hour, 100 mg/m³ over 15 minutes.
Step 3 (20 minutes): Close all windows and doors, then time how long it takes before the air feels stale — odor returning, slight stuffiness. A room that feels stale within minutes suggests a low air change rate; one that stays comfortable for half an hour suggests you are near or above 1 ACH.
On narrow screens, swipe or scroll the plate sideways.
Step 4 (15 minutes): Count the combustion appliances — furnace, water heater, gas stove, fireplace — and confirm each has an outside air path. Combustion products are on the common indoor pollutant list and respond to ventilation, but only if the appliance can draw replacement air.
Step 5 (10 minutes): Estimate your winter ACH bracket. If the house is tightly air-sealed, expect around 0.50; if loosely air-sealed, around 1.47. Note where you sit in that range and whether you ventilate deliberately.
Typical failures at this stage: reading a CO number without its averaging window; assuming a purifier handles CO₂; treating one stale-smelling room as a whole-house problem; skipping the combustion appliance check because the furnace is in the basement.
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