Air is the quietest system and, in one respect, the deadliest. Bring cooking and heating indoors — as an off-grid household must — and you invite an invisible, odourless killer to the table: carbon monoxide. It gives no warning and kills people in their sleep every winter. But it isn’t the only air problem: for weeks each year the air outside turns against you too, and a household needs an answer to both.
Any flame or engine indoors — stove, lamp, generator, heater — makes exhaust that must go out, not build up. Carbon monoxide is the one that kills quietly.
Crop-burning haze, dust storms, wildfire smoke, or an illness passing through a full house — the times you must filter the air itself.
Seal a house tight for warmth and you trap moisture and staleness — mould, and lungs that never quite clear.