Turn your plaster and stretch ceilings into an igloo

What makes an igloo liveable

An igloo is built from snow, at a temperature well below zero outside, and it stays liveable inside. Three mechanisms combine: the snow holds still air, its inner surface turns to ice and cuts infiltration, and its whiteness sends the occupants' own radiation back to them.

Transposed to a ceiling

The reflective insulation plays the part of the ice: it closes the plenum and stops air movement. Its two aluminium faces play the part of the whiteness: they send infrared back instead of absorbing it. And the sealed air gap plays the part of the bubbles trapped in the snow.

The return up the wall

An igloo is not a roof resting on walls, it is a continuous envelope. The insulation therefore returns up the wall over a certain height, to close the volume instead of letting it leak at the edges. It is a fitting detail, and it changes the measured result.

What the plenum then becomes

The volume above the fabric stops being wasted space. It recovers the heat produced in the room by the occupants, the cooking, the lighting and the appliances, and sends it back down. The system is passive before it is active.

What that assumes

An existing plasterboard ceiling works, and so does a stretched fabric. The condition is not the nature of the substrate but the continuity of the envelope: a plenum open onto a loft will never produce this effect.

The principle of passive recovery is developed on the page about the passive radiant ceiling, and the system on the Ceilingo radiant plaster ceiling page.