Upgrade your QuietCool system for the winter months with the QuietCool Winterized Insert. Designed with an impressive R50 insulation value, this insert is ideal for cold, snowy climates. Simply remove the fan grille, slide the insert into place, and re-install the grille to significantly reduce heat loss. It seals off the damper box, keeping warm air inside and cold air out - making your home more comfortable and energy efficient all winter long.