As crucial as renewing the seals periodically is choosing the correct seal for the windows and doors. If your previous weatherstrip has worked well, you should usually select a similar seal to replace it. There are various types of seals, e.g., groove seals, self-adhesive seals and silicone seals. O-profile (omega) groove seals are placed into grooves in your door/window. The groove is already in the door/window in most new windows. For older doors and windows, we recommend you use self-adhesive seals or contact a professional if you'd like to switch to groove seals. We recommend that you don't make the grooves yourself.
Measuring the gap
You can measure the gap with, e.g., blue tack. You should measure both the inner and outer windows separately. Place the blue tack in place of the seal and close the window/door. Measure the width of the flattened blue tack and choose a seal that's 2-3 mm thicker than blue tack.
1 - 2 mm
Width of the seal (mm)
3,5 - 4,0