Fit a Pleated Blind With Luxaflex Duette Fabric in 6 Steps for 25% Less Heat Loss

Cell size and air pockets set the insulation figure

Duette fabric uses a double-honeycomb cross-section, with two rows of trapped-air pockets placed back to back. The still air inside those pockets is the working layer at the cold pane. Luxaflex publishes thermal data across the Duette range, with the largest gains coming from the wider 25mm and 32mm cell sizes, because a larger cell holds a thicker layer of dead air.

The 25 percent heat-loss reduction figure assumes a face-mount installation where the fabric covers the reveal and the side gaps are kept small. Put the same blind inside a deep recess with 30mm of air moving around each edge and the figure falls away, because convection currents can pass straight beside the cells.

A blind ordered 20mm narrower than the architrave will look tidy and insulate poorly. Order it to cover the reveal opening plus a 40mm to 50mm overlap on each side, and the cells cover the cold zone properly. The same principle applies to draught-proofing fixed glazing, so the bracket position affects the thermal result as much as the fabric specification.

Steps 1 and 2: mark the brackets and level the rail

Hold the made-to-measure blind against the window before making any mark, and decide whether it will be face-mounted or recess-mounted. For the 25 percent heat-loss figure, use a face-mount above the reveal. Mark the bracket centres so the headrail clears the architrave and the fabric can drop without catching the window handle.

Luxaflex supplies two brackets for blinds up to about 1200mm wide and adds a third centre bracket beyond that. A 1.6m living-room window therefore needs three fixing points, spaced evenly across the span.

Run a spirit level across the two outer marks before drilling. A headrail that is 2mm out of level across 1.5m leaves a visible wedge of light at one bottom corner, and that gap becomes a thermal leak on honeycomb fabric. Mark the screw holes through the bracket itself so the spacing matches the hardware exactly.

On a plasterboard wall, use the supplied plugs or proprietary cavity fixings rated for the headrail weight. On solid masonry, a 6mm masonry bit and a standard brown plug will hold the bracket securely. Drill, plug, and screw the outer brackets first, then hang a string line or re-check with the level before fixing the centre bracket, otherwise the middle fixing can pull the rail into a curve.

Step 3: clip the headrail into place

Lift the headrail to the brackets, engage the back lip into the bracket hook, and rotate the front down until the clip snaps shut. Each bracket should give a positive click, followed by a gentle downward tug to confirm the rail is locked before you let go.

Step 4: fit the cord lock, wand, or motor

Duette blinds ship with three possible control setups, and the fitting work changes with the mechanism. The standard corded version arrives with the cord lock already assembled inside the headrail, so the remaining job is routing the cord cleat.

Fix the supplied child-safety cleat to the architrave at least 1.5m above floor level. That is the height targeted by the EN 13120 cord-safety standard to keep loops out of a small child’s reach. Wind the excess cord around the cleat after every use.

The cordless SmartCord version shortens the visible control run, while the PowerView motorised version changes Step 4 into a pairing job. On PowerView, the battery wand or hardwired motor is already housed inside the headrail. Hold the Luxaflex Pebble remote within a metre of the headrail, press and hold the pairing button until the blind jogs, then assign it to a channel. The same setup can also be completed through the PowerView app over the local radio link.

A motorised Duette uses very little standby power. The rechargeable wand typically runs for months between charges on a bedroom-sized blind, so the cabling choice mostly comes down to whether app scheduling is wanted.

For a TopDown-BottomUp configuration, the second cord set or second motor controls the lower rail independently. Set both limits before the fabric is fully loaded, since each rail has its own stopping point.

Step 5: set the bottom rail and travel limits

With the headrail fixed, lower the fabric fully and check that the bottom rail sits parallel to the sill. Corded blinds leave the factory with the rail already attached, so this check is mainly about level and contact. On a motorised unit, run the blind to its lowest point and set the down-limit so the cells compress just enough to seal against the sill. Leave the fabric standing a few millimetres proud, because over-compressed Duette cells lose their air pocket at the place where cold air tends to pool.

Raise the blind fully and set the up-limit so the stack clears the glass and tucks under the architrave. Check both limits twice. A motor that overruns either end strains the lift cords running inside the honeycomb.

If the rail hangs even slightly skew at this stage, the fault is usually a bracket that drifted during fixing. Re-drilling one bracket hole now is easier than keeping a permanent light gap. Measure the gap at each bottom corner with a steel rule; anything over 3mm difference from side to side is worth correcting.

Step 6: check the side gaps that control the thermal result

Stand inside the room with the blind down and daylight behind it, then look along both vertical edges. A continuous bright line down one side means the fabric is failing to overlap the reveal. That channel is where warm room air can slide down the cold glass and shed heat.

On a face-mount blind already cut to size, the permanent cure is usually a wider fabric on the next order, since the existing blind cannot be stretched. A temporary improvement can come from fitting the optional Luxaflex side channels, which bridge the gap.

Use the same overlap target that set the original measurement: 40mm to 50mm of fabric past the reveal opening on each side, with similar coverage at the top behind the headrail. At the head, a face-mount rail can still leave room air access above the fabric unless a pelmet or a recess-mount closes that path. Hold a sheet of paper against the edge with the heating on and the blind down. No detectable draught at the edges is the condition under which the published 25 percent figure holds. Run the same check at the sill; the bottom rail should sit close enough that the paper meets resistance underneath.

A worked example for one bedroom window

Take a bedroom window with a reveal opening 900mm wide and 1200mm high. For face-mount fitting, order the Duette fabric at 990mm wide, giving 45mm overlap on each side, and choose a 1260mm drop to cover the reveal top and reach the sill. With 32mm cells, the dead-air layer is at its thickest. Against single glazing, the relative gain is largest because the starting heat loss is highest. Two brackets carry this width comfortably, set roughly 80mm in from each end, with the cord cleat fixed at 1.6m so the safety loop clears the floor.

Drilling into plaster takes about 20 minutes including levelling. Clipping the headrail, routing the cord, and setting the bottom rail adds another 15 to 20 minutes. The measurable difference shows at the glass surface: with the blind down on a cold night, the inner face of the fabric sits noticeably warmer than bare glass would. That warmer fabric face is the visible sign of the insulation gain, and it also explains why less condensation runs down the pane by morning.