Inside mount vs outside mount blinds: how to choose

Before fabric, before colour, before motorized or not, every window covering comes down to one decision: does it sit inside the window opening or outside it? Get this right and the rest follows. Get it wrong and the best shade in the world will leak light, catch on the handle, or look like an afterthought.

Inside mount means the blind sits within the window frame, in the reveal. It is the clean, built-in look most people picture. The window trim stays visible, the shade disappears when it is raised, and nothing sticks out from the wall. It is the right choice for most modern windows with a deep enough frame.

The catch is depth and light. You need enough depth in the reveal to hold the brackets, usually one to two inches depending on the product, more for motorized. And an inside-mounted shade always has a small gap at each side so it can move, which means a thin line of light at the edges. In a living room nobody notices. In a bedroom for a shift worker, it matters.

Outside mount means the blind sits on the wall or the trim above the window and overlaps the opening on all sides. It covers more, blocks more light, and hides a window that is slightly out of square or has shallow trim. It is the honest answer for blackout: an outside-mounted blackout roller with a few inches of overlap on each side gets a room genuinely dark.

The trade-off is that it is more visible. The shade and its cassette sit proud of the wall, and the window trim is covered when the shade is down. Choosing a fabric-wrapped cassette and a colour that suits the wall makes this look intentional rather than bulky.

Some quick rules we use at every consultation. Bedrooms and nurseries that need darkness: outside mount, or inside mount with side channels. Kitchens over a sink or windows with cranks and handles that stick out: outside mount so the shade clears them. Deep, square, modern windows in a living space: inside mount for the clean look. Shallow frames, old houses, bay windows that are not square: outside mount hides the sins. Condos with aluminum frames and concrete above: often outside mount on the wall, which we confirm on site.

Measuring is different for each. Inside mount: measure the exact opening width in three places and use the narrowest, and we take the factory deduction so the shade fits and operates. Outside mount: measure the area you want covered, usually the opening plus two to three inches on each side and above. Our measuring guides walk through both, and if you would rather not think about it, the in-home measure is free and the fit becomes our problem.