Window Vents

Trickle Vents or Rotary Vents?

• Trickle vents fit along the top of the window frame or sash, over slots cut through the frame. An outside canopy or grille keeps rain and insects out, and the inside vent has a slide or flap so you can open and close it. These are the most common vents on uPVC windows.
• Rotary vents fit through a round hole in the glass and turn with the wind or the air flow. In double glazing the hole is made when the sealed unit is manufactured, so a rotary vent normally replaces an existing one or goes into a new glass unit.

Frequently Asked Questions

Do trickle vents stop condensation?

They help. A trickle vent gives a constant trickle of fresh air that carries moist air out, which reduces condensation on the glass. Heating, extractor fans and drying clothes outside all make a difference too.

Can I fit a trickle vent to a window that doesn't have one?

Yes, but slots must be cut through the frame with the correct router or cutter, so it's a bigger job than a straight replacement. Replacing an existing vent with a matching one only needs a screwdriver.

Can I add a rotary vent to my double glazing?

Not to an existing sealed unit. The hole has to be made when the glass unit is manufactured, so you would need a new sealed unit with a vent hole. Replacing an existing rotary vent is straightforward.

Not sure which vent you have?

Send us photos of the vent inside and outside with a tape measure in shot through our part identification service and we will find a match.