Cellular honeycomb blinds

Why insulation matters in Pretoria

Waterkloof's problem is not average temperature, it is swing. A clear winter day here can run twenty degrees warmer than the night that follows it, and single-glazed windows lose that warmth as fast as the house gains it. A double-cell honeycomb across the glass traps a layer of still air between the room and the pane, which slows the loss at night and the gain in the afternoon.

It works the other way too. On a January afternoon in a west-facing study, a light-coloured cellular blind will hold a noticeable amount of heat at the window instead of letting it into the room.

Top-down, bottom-up

The cleverest thing a cellular blind does is open from either end. Drop the top rail and you get sky, daylight and no view in from the street. Raise the bottom rail and you get the garden. On a Brooklyn or Hazelwood street window that sits close to the pavement, this is the detail that makes the room usable.

Practical notes

• Single cell for slimline windows; double cell where insulation is the point.
• Light-filtering and blockout fabrics — blockout cellular is excellent in a nursery, because it is quiet as well as dark.
• Cordless and motorised options; the stack is very small, so it hides neatly in a reveal.
• Perfect for shaped and skylight openings, where the pleat can be tensioned between two tracks.

Honest note

Cellular fabric is a pleated structure, so it is not the blind for a room where things get knocked about — a busy family passage, a doorway that takes a bicycle every afternoon. In those rooms an aluminium venetian or a roller will take the punishment better.