How to Hang Curtains Properly for Better Light Blocking and Taller-Loo

TL;DR (30-second answer): To block more light and make windows look taller, hang the rod higher and wider than the window, use enough fabric for fullness, and choose an outside mount when light leaks are the priority. Aim for curtains that land at your intended endpoint (usually near the floor) and extend the rod past the frame so panels cover the edges when closed and stack off the glass when open. For deeper formulas on rod height and curtain length, see this rod-height formula guide and this curtain-length guide.

Quick Problem Breakdown: Why Curtains Leak Light (Even When Fabric Is Thick)

Most “light leak” complaints come from fit and placement, not the fabric alone. If the rod is mounted too close to the window frame—or the curtains aren’t wide enough—light sneaks in around the top and sides.

Top gap: Rod is mounted too low, leaving a bright strip above the curtain.
Side gaps: Rod is too narrow or panels don’t have enough overlap past the frame.
Insufficient fullness: Flat panels don’t seal well and look less polished.
Wrong mount choice: Inside mounts often leave more edge light than outside mounts.
Uneven install: A slightly tilted rod creates visible gaps and an unbalanced look.

Light control can also matter for comfort and efficiency—energy guidance from the U.S. Department of Energy explains how window coverings can help regulate indoor conditions when used appropriately: Energy Efficient Window Coverings (DOE).

Solution 1: Measure Like a Pro Before You Drill (Width, Height, and Endpoint)

Measure first, then decide placement. A small measuring mistake becomes a permanent-looking gap once hardware is up.

Measure each window in three places (top/middle/bottom for width; left/middle/right for height).
Decide your curtain endpoint: just below sill, grazing the floor, or slightly pooling.
If using rings or clips, measure from the point where the curtain will actually hang.
Record everything window-by-window (don’t reuse measurements across “similar” windows).

Key takeaway: The most reliable way to avoid light leaks is to measure each window in multiple spots and choose curtain length based on the exact hanging point and endpoint.

Solution 2: Choose the Right Mount (Inside vs. Outside) Based on Your Goal

Your mount choice is a performance decision. If light blocking is the priority, an outside mount is usually the easier win because it allows more overlap around the frame.

Inside mount: Best when you want to showcase nice trim and don’t need maximum coverage.
Outside mount: Best when you want to reduce edge light and visually “frame” the window bigger.

For shoppers who want light control options, start with a collection built for that goal, then refine by color and lining: custom blackout curtains.

Key takeaway: If you want better light blocking, choose an outside mount so the curtain can overlap the window frame on all sides.

Solution 3: Hang the Rod Higher to Make the Window Look Taller (Without Making Curtains Too Short)

Hanging curtains higher draws the eye upward and can make ceilings feel taller—but only if your curtain length still reaches your intended endpoint.

Pick your endpoint first (many rooms look cleanest when curtains graze the floor).
Raise the rod to lift the visual height of the window while keeping the curtain length workable.
In small rooms, placing the rod closer to the ceiling can create a stronger height effect.

Use a clear formula with room-size scenarios here: How High Should You Hang Curtain Rods? A Simple Formula for Small and Large Rooms.

Key takeaway: To make windows look taller, mount the rod higher than the frame while ensuring the curtains still reach your chosen endpoint.

Solution 4: Make the Rod Wider Than the Window to Reduce Side Gaps

Rod width is one of the most overlooked reasons for side light leaks. When the rod is too narrow, the curtain panels can’t cover the frame edges effectively.

Extend the rod beyond the window so the curtains can sit on the wall when closed.
Wider placement also lets curtains stack off the glass when open, making the window feel larger.

Key takeaway: A wider rod reduces side light gaps because it allows the curtain panels to overlap the window edges instead of stopping at the frame.

Solution 5: Add Fullness and Level the Install for a Clean, Gap-Reducing Finish

Even well-chosen curtains can look off if they’re too flat or the rod isn’t level. Fullness improves coverage and gives the fabric a more finished drape.

Use enough total fabric width to avoid a flat, stretched look when the curtains are closed.
Dry-fit bracket positions before drilling and check with a level.
Level to the room (not the ceiling), since many ceilings and floors aren’t perfectly straight.

Key takeaway: Proper fullness plus a level rod creates a cleaner seal and a more polished look, which helps reduce visible light gaps.

When You Must Replace Curtains (Not Just Rehang Them)

Sometimes placement fixes aren’t enough. Consider replacing curtains when the product itself can’t meet your goal—even with perfect hardware placement.

Your curtains are too short to reach the desired endpoint after raising the rod.
Your panels are too narrow to cover the window plus overlap (even with a wider rod).
You need a stronger light-control category for bedrooms or media rooms (start here: custom blackout curtains).
Your fabric has thinned, faded, or no longer hangs evenly after washing or long-term use.

Key takeaway: If curtains can’t reach the right length or provide enough width for overlap, replacing them is often the fastest path to better light blocking and a cleaner look.

FAQ

How do I hang curtains to block more light without changing the window?

Use an outside mount, hang the rod wider than the frame for overlap, and ensure the curtains are long enough to reach your desired endpoint.

What’s the biggest cause of light leaking around curtains?

Most leaks come from rod placement and insufficient overlap—especially a rod that’s too low or too narrow.

How high should I hang curtain rods for a taller-looking window?

Hang the rod higher than the window frame while keeping the curtains long enough for your intended endpoint; for a simple formula, see this rod-height guide.

How long should curtains be if I want them to look “designer” but still practical?

Many homes look best with curtains that graze the floor; use this reference to choose the right endpoint: How Long Should Curtains Be?.

Can I hang curtains from the ceiling to reduce light gaps and add height?

Yes—ceiling mounting can increase perceived height and can work as a room-divider approach; follow this guide: How to Hang Curtains from the Ceiling.

Why does light at night matter for sleep?

Public health guidance notes that light and dark strongly influence circadian rhythms; reducing bright light at night can support better sleep: Effects of Light on Circadian Rhythms (CDC/NIOSH).

Do window coverings affect energy comfort, or is it just about style?

The U.S. Department of Energy explains that window coverings can help regulate indoor temperatures and comfort depending on type and use: Energy Efficient Window Coverings (DOE).