As important 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 choose a similar seal to replace it. There are various types of seals out there; e.g. groove seals, self-adhesive seals and silicone seals. O-profile (omega) groove seals are placed into grooves in your door/window. In most new windows this groove is already in the door/window. For older doors and windows we recommend you to use self-adhesive seals or to contact a professional in case you'd like to switch to groove seals. We recommend that you don't make the grooves yourself.