Inside Mount vs Outside Mount
Every shade in your home is mounted one of two ways: inside the window opening, or outside it on the wall or trim. The choice affects how the room looks, how much light escapes at the edges and whether a product physically fits at all.
Inside mount
The shade sits within the window opening, with the trim visible around it. It is the more built-in, architectural look, and it keeps the wall around the window clear.
- Cleanest appearance; the window trim frames the shade
- Requires enough clear depth for the headrail or cassette
- Always leaves a small light gap at each side — that is a property of the mount, not a fault
- Shows an out-of-square opening, because the straight edge of the shade sits against the tapering reveal
Outside mount
The shade is fixed above the opening and covers it. This is the mount for shallow reveals, uneven openings, and any room where light control matters more than the built-in look.
- No depth requirement inside the opening
- Overlap on all four sides dramatically reduces edge light — the reason bedrooms usually get this mount
- Hides an out-of-square or damaged opening
- Can make a small window look larger, because the covered area is bigger than the glass
- Needs a solid mounting surface and clearance from crown moulding or existing hardware
Side by side
Seen together, the difference is mostly about where the edges of the shade land and where light is allowed to pass. Neither mount is better in the abstract; they solve different problems.
How to choose, room by room
- Bedroom that must be dark — outside mount with generous overlap, or an inside mount with side channels where the trim allows
- Living room with attractive trim — inside mount, so the joinery stays visible
- Shallow condo window pocket — outside mount, or a slim product chosen specifically for the depth available
- Out-of-square older opening — outside mount, which hides the discrepancy
- Window with a handle or crank in the reveal — outside mount, or an inside mount planned around the obstruction
- Sliding glass door — outside mount above the opening, so the shade clears the track and the door leaf
Light gaps and privacy
An inside-mounted shade is always slightly narrower than the opening so it can travel freely, so a thin line of light appears at each side. In a living room, nobody notices. In a bedroom at seven in the morning, everybody does.
The two reliable ways to remove that light are an outside mount with real overlap, or side channels on an inside mount. We decide which is workable when we look at the trim at the measure.
Ask us to check the mount at your windows
DIY measurements are useful for planning and preliminary estimates. Final measurements for custom-made window treatments should be verified professionally before production. Our in-home measure is free across Miami-Dade, Broward and Palm Beach counties — up to 100 miles around Miami.
Frequently asked questions
Which mount is better for blackout?
Outside mount, in almost every case. The overlap on all four sides is what removes edge light — the fabric alone never does it.
How much depth does an inside mount need?
It depends entirely on the product: a slim roller needs the least, a cassette or dual shade system needs considerably more. We confirm the depth against the specific product at the measure.
Can different windows in the same room use different mounts?
Yes, and often they should — but keep the bottom or top lines aligned where windows are on the same wall, or the room reads as inconsistent.