A roof window refurbishment system, comprising a roof window having a stationary frame with a top frame member, a bottom frame member, and two side frame members defining a central opening, and, placed within the stationary frame, a sash with sash members carrying a pane, in which each frame member (100, 200, 300) of the stationary frame has an inner side facing the central opening, each of said inner sides having an exterior portion (102, 202, 302) and an interior portion (101, 201, 301), the refurbishment system further comprising a set of capsules (110, 210, 310; 120, 220, 320) adapted to be connected to the frame members (100, 200, 300) of the stationary frame in a mounted condition, the set of capsules (110, 210, 310; 120, 220, 320) comprising: a top capsule (310; 320) having a closed surface (311; 321) and an exposed surface (312; 322), adapted to be mounted on the top frame member with the closed surface (311; 321) facing the top frame member and the exposed surface (312; 322) facing the central opening, and the top capsule having an interior section such that the top capsule (310; 320) covers the interior portion of the inner side of the top frame member in the mounted condition; a bottom capsule (210; 220) having a closed surface (211; 221) and an exposed surface (212; 222), adapted to be mounted on the bottom frame member with the closed surface (211; 221) facing the bottom frame member and the exposed surface (212; 222) facing the central opening, and the bottom capsule having an interior section such that the bottom capsule (210; 220) covers the interior portion of the inner side of the bottom frame member in the mounted condition; and two side capsules (110; 120) each having a closed surface (111; 121) and an exposed surface (112; 122), each adapted to be mounted on respective side frame members with the closed surface (111; 121) facing the respective side frame member and the exposed surface (112; 122) facing the central opening, and each side capsule having an interior section such that each side capsule (110; 120) covers the interior portion of the inner side of a respective side frame member in the mounted condition, wherein at least one of the capsules (110, 210, 310; 120, 220, 320) has an exterior section (113, 213, 313; 123, 223, 323) adapted for covering at least part of the exterior portion of the frame member and/or a sash member in said mounted condition, and wherein at least one of the capsules (110, 210, 310; 120, 220, 320) further comprises a first and a second end, wherein the ends are provided with flexible flanges (119; 116) adapted for engaging the frame member to provide a snap lock; characterized in that the interior section of at least one of the capsules (110, 210, 310; 120, 220, 320) has a thicker profile relative to the exterior section. a top capsule (310; 320) having a closed surface (311; 321) and an exposed surface (312; 322), adapted to be mounted on the top frame member with the closed surface (311; 321) facing the top frame member and the exposed surface (312; 322) facing the central opening, and the top capsule having an interior section such that the top capsule (310; 320) covers the interior portion of the inner side of the top frame member in the mounted condition; a bottom capsule (210; 220) having a closed surface (211; 221) and an exposed surface (212; 222), adapted to be mounted on the bottom frame member with the closed surface (211; 221) facing the bottom frame member and the exposed surface (212; 222) facing the central opening, and the bottom capsule having an interior section such that the bottom capsule (210; 220) covers the interior portion of the inner side of the bottom frame member in the mounted condition; and two side capsules (110; 120) each having a closed surface (111; 121) and an exposed surface (112; 122), each adapted to be mounted on respective side frame members with the closed surface (111; 121) facing the respective side frame member and the exposed surface (112; 122) facing the central opening, and each side capsule having an interior section such that each side capsule (110; 120) covers the interior portion of the inner side of a respective side frame member in the mounted condition, wherein at least one of the capsules (110, 210, 310; 120, 220, 320) has an exterior section (113, 213, 313; 123, 223, 323) adapted for covering at least part of the exterior portion of the frame member and/or a sash member in said mounted condition, and wherein at least one of the capsules (110, 210, 310; 120, 220, 320) further comprises a first and a second end, wherein the ends are provided with flexible flanges (119; 116) adapted for engaging the frame member to provide a snap lock; characterized in that the interior section of at least one of the capsules (110, 210, 310; 120, 220, 320) has a thicker profile relative to the exterior section.