What Brightness Do I Need for a Shop Window Display?
The one decision that determines whether your window screen is vivid and powerful — or invisible. Everything you need to know about cd/m², nits, window orientation and which screen is right for your specific position.
Brightness is the single most important specification when choosing a shop window display — and the one most frequently misunderstood. Get it right and your screen looks stunning in any weather. Get it wrong and you have spent money on a dark rectangle that passersby cannot read. This guide settles the question definitively.
The short answer is this: for a shaded or north-facing window, 800cd/m² is sufficient. For most UK high street windows that receive any direct or strong indirect daylight, you need 3,500cd/m². Below we explain exactly why — and how to identify which category your window falls into.
1. What Is cd/m² — And What Does It Mean for Your Window?
Screen brightness is measured in candelas per square metre (cd/m²), also called nits — the two terms are identical. One nit equals one cd/m². You will see both used interchangeably in product specifications.
The number represents how much light a screen emits from each square metre of its surface. The higher the number, the brighter the screen and the more capable it is of competing with ambient light in its environment — including the daylight pouring through your shop window.
| Screen Type | Typical cd/m² | Window Use |
|---|---|---|
| Consumer TV (home) | 250–400 cd/m² | Completely invisible through glass in any daylight |
| Standard commercial indoor display | 450–700 cd/m² | Not suitable for window use — washes out in overcast light |
| 800cd/m² Window Display | 800 cd/m² | Suitable for shaded, north-facing or covered window positions only |
| 3,500cd/m² Ultra High Brightness | 3,500 cd/m² | Suitable for most UK high street windows in direct daylight ✓ |
If you see a screen described as "3,500 nits" and another described as "3,500cd/m²" — they are identical. The unit nit (nt) is an informal name for the candela per square metre. Always compare like with like: check the number and the unit together.
2. Why Brightness Is Everything for a Window Display
A screen is visible when it emits significantly more light than the ambient light around it. The moment ambient light approaches or exceeds screen brightness, the image washes out. Through shop window glass, this effect is compounded further.
Here is the physics in plain terms:
⚠️ The Glass FactorWindow glass absorbs and reflects a significant portion of screen brightness before it reaches a viewer on the pavement. Standard glass reduces effective transmitted brightness by 20–30%. Treated, tinted or double-glazed shop glass can absorb even more. This is why screens that appear adequate indoors look completely washed out when placed behind shop glass — the rating on the box is not the brightness the customer actually sees.
3. The Two Tiers — 800cd/m² vs 3,500cd/m² Explained
Khazina Digital offers two distinct brightness tiers for window display applications. Understanding the difference — and which tier your window needs — is the most important decision you will make:
- North-facing shop windows (no direct sun, ever)
- Windows under permanent canopy or deep recess
- Basement-level or semi-underground retail
- Interior-facing position (screen faces inward to customer)
- Indoor atrium positions with indirect light only
- East-facing — only acceptable if morning sun is fully blocked
- South-facing — will wash out in any daylight conditions
- West-facing — afternoon sun makes screen invisible
- Standard high street position receiving any direct daylight
- South-facing windows — full direct sun all day
- West-facing — intense afternoon sun
- East-facing — morning direct sun
- High street positions with any direct or strong indirect light
- Shopping centre glass atrium positions
- Covered positions that still receive strong reflected light
- Any window where 100% year-round visibility is required
- North-facing — works here too (excess brightness turns down)
When in doubt, choose 3,500cd/m². Excess brightness can always be reduced in screen settings, saving electricity. But insufficient brightness cannot be fixed after purchase — you cannot add nits retrospectively. A single bright summer afternoon will expose the limitations of an under-specified screen, and you will wish you had spent the extra £1,271+VAT on the right product from the start.
4. Your Window Orientation — The Definitive UK Guide
Window compass orientation is the most reliable predictor of the brightness tier you need. Here is exactly what each direction means for your screen specification in the UK:
North-facing windows receive no direct sunlight at any time of year in the UK. Ambient light levels are lower and more consistent. 800cd/m² is usable in this position — but only if the window is genuinely always in shade with no reflected light from buildings opposite or a bright open space nearby. If any direct or strong reflected light ever reaches the window, upgrade to 3,500cd/m².
East-facing windows receive direct morning sun — typically from sunrise until around noon on clear days. For much of the UK trading day this position is also exposed to strong indirect light. 800cd/m² will be unreadable during morning trading hours. 3,500cd/m² is required for reliable visibility throughout the full business day.
West-facing windows receive direct afternoon and evening sun — precisely during peak trading hours for most UK food, retail and hospitality businesses. This is one of the most demanding positions for a window display. 800cd/m² will appear invisible from mid-afternoon. 3,500cd/m² is essential. This is not a position where saving on hardware cost is wise.
South-facing is the most challenging UK window position for a display screen. Direct sun from late morning to mid-afternoon for most of the year creates extreme ambient light conditions. This is the position most often cited in screen failure stories. 3,500cd/m² is the absolute minimum. For particularly sunny, exposed south-facing positions, the additional investment in 3,500cd/m² is not optional — it is the difference between a working screen and an expensive dark rectangle.
Special Cases
| Position Type | Recommended Brightness | Reason |
|---|---|---|
| Under a permanent canopy (all directions) | 800cd/m² may work | Blocked direct sun — but verify no strong reflected light from pavement or opposite buildings |
| Shopping centre unit with glass atrium | 3,500cd/m² | Diffuse overhead daylight is intense — equivalent to outdoor indirect light conditions |
| Basement or below-street-level shop | 800cd/m² acceptable | Minimal ambient daylight — screen faces semi-underground position |
| Deep window recess (over 1m deep) | 800cd/m² may work | Physical depth shades the screen from direct light — verify in situ |
| Interior-facing (screen faces into shop) | Standard commercial display sufficient | No window glass in the light path — not a window display application |
5. Common Brightness Myths — Busted
6. Khazina Digital Window Display Range — Matched by Brightness
Every product below is verified from the live khazinadigital.com website as of March 2026. Free bespoke animated design worth £150+VAT is included with every screen. Click any product to view full specifications:
800cd/m² Digital Window Display
The right choice for north-facing, permanently shaded or covered window positions where ambient light is consistently low. Commercial-grade, rated for continuous operation, built-in Android media player. FREE bespoke animated design included.
Ultra High Brightness Window Display — 3,500cd/m²
The right choice for the vast majority of UK high street shop windows. 3,500cd/m² sunlight-readable — vivid and clear in direct UK daylight, south and west-facing windows and bright summer sun. The most popular choice for UK retailers, estate agents, salons and food businesses. FREE bespoke animated design included.
Double-Sided Window Display — 3,500cd/m²
Two 3,500cd/m² panels in one installation — street-facing for passerby impact and inward-facing for customers inside simultaneously. One power source, one media player. Maximum impact from a single window position. FREE bespoke animated design included.
Hanging Double-Sided Window Display
Ceiling-hung double-sided window display — visible from the street outside and inside the shop simultaneously, mounted from an integrated ceiling bracket without wall fixing. Ideal for window positions where wall mounting is not possible. FREE bespoke animated design included.
P2.5 High Brightness LED Window Displays
Large-format high-brightness LED window display delivering video wall-scale impact for flagship locations. Modular, seamless, scalable. Sunlight-readable for near-window positions. FREE bespoke animated design included.
7. Quick Self-Assessment — What Brightness Do You Need?
Answer these questions about your specific window to find your brightness requirement:
| Question | Answer | Recommendation |
|---|---|---|
| Does your window ever receive direct sunlight at any time of day or year? | Yes | 3,500cd/m² required |
| Does your window face south or west? | Yes | 3,500cd/m² required |
| Is your window in a shopping centre with a glass atrium or roof? | Yes | 3,500cd/m² required |
| Can you clearly read a printed A4 paper in your window at midday without artificial light? | Yes — it's bright | 3,500cd/m² required |
| Is your window permanently shaded — under a canopy, in a deep recess or below street level? | Yes, always shaded | 800cd/m² may be sufficient |
| Does your window face north with no reflective surfaces opposite? | Yes, consistently dim | 800cd/m² acceptable |
| You answered "yes" to all the shaded questions but have any doubt at all? | Any doubt | Choose 3,500cd/m² — it can always be dimmed down |
If you have described your window position and are still unsure, call 0121 594 0828. Our team has been advising UK businesses on window display specifications since 2013. Tell us your window's compass direction, whether you get direct sun, and what street it faces — we will tell you exactly which product you need in under two minutes. Free advice, no obligation.
8. Frequently Asked Questions
Shop UK Window Displays — 800 to 3,500cd/m²
Two brightness tiers for every UK window position. Commercial-grade, FREE bespoke animated design included, UK supplier since 2013.