hauntedicecreamvan

If you go for a higher-end trickle vent (e.g. humidity-sensitive) check that they can physically fit on the frames in terms of width/height. There used to be a product sold by Aereco (their "EMM" vent), that were quite slimline at only 27mm height. I fitted a few before putting in a PIV unit and they work well for opening and closing themselves based on humidity levels. Now, Aereco only sell the EMM2 which looks similar to those offered by Brookvent and is a much larger unit (the Brookvent HY is 45mm height!). I think out of the standard vents (like the Slotvent), they're all much the same as each other. The only consideration you might have is upward-deflection or downward facing for the interior part. Upward-deflection vents should be less prone to feeling drafts. They also do a better job of hiding the holes, in case you are incapable of drilling holes in a straight line like whoever did some for my home's previous owner.