Ventilation is the movement of air through a space, replacing stale, moist air with fresh air so that moisture can escape. GOV.UK's damp guidance puts it simply: where a space is inadequately ventilated, moisture in the air cannot escape and is more likely to cause condensation.
At Wigwam
Our units aren't climate-controlled, and we don't publish whether individual units or buildings have their own vents. If that matters for what you're storing, ask us about your site before you book. Either way, pack for airflow as below, and don't rely on the unit to move air for you. You can't add ventilation to a unit yourself. Our terms don't allow you to make alterations to or attach anything to the unit's surfaces (clause 22(d)), or to connect any utilities or services unless we've authorised it (clause 22(e)), so there's no fitting a vent or running a fan.
Our terms do care about air around your goods in one case: anything with a built-in battery must be stored so it isn't stacked and air can circulate (clause 20.1(b)).
Airflow you can control
In a storage unit, the air that matters most is the air around your things, and that's in your hands:
- leave a gap between your goods and the walls;
- keep things off the floor on a pallet or a layer of hard boxes;
- don't wrap fabric in sealed plastic. The Canadian Conservation Institute advises against plastic garment bags "because there is no air circulation (which can encourage moisture to build up)";
- don't pack the unit so tight that nothing can breathe.
Airflow moves moisture on; it can't remove moisture you pack in. Clean and fully dry going in still comes first.
Related terms: Condensation · Breathable cover · Damp
Related questions: How do I stop clothes going musty in a storage unit? · Who is responsible if mould appears in my storage unit?