If you make or specify signage, you have probably been asked the same question twice: should this project use traditional glass neon or LED neon flex? The honest answer is that glass neon is no longer the default, but it is still the better choice in a few specific situations. This guide compares the two on the things that actually decide a project: power, running cost, lifespan, light quality, bending, weather resistance, certification and total installed cost.
How each one actually produces light
Glass neon is a sealed glass tube with an electrode at each end, filled with a noble gas — neon for the familiar red-orange, argon with a mercury drop for blues and greens. A step-up transformer converts mains power to somewhere between 2,000 V and 15,000 V to strike and sustain the arc. Each colour is a different gas mix, so a multi-colour sign means multiple tube runs, multiple transformers and multiple circuits.
LED neon flex is a flexible strip of LEDs inside a silicone or PVC jacket that has been extruded into a tube profile. Phosphor-coated LEDs produce the colour, so one tube type can deliver any colour, and RGB or RGBW versions can change colour on demand. Power is low-voltage DC — usually 12 V or 24 V — so the transformer becomes an ordinary constant-voltage driver.
Power, voltage and what it means on site
| Property | Glass neon | LED neon flex |
|---|---|---|
| Operating voltage | 2–15 kV at the tube, via transformer | 12 V / 24 V DC |
| Typical power | 8–15 W per metre, plus transformer losses | 5–10 W per metre at full output |
| Wiring | High-voltage runs, fire-rated sleeving, separate enclosure | Standard low-voltage cable |
| Colour changes | New tube run per colour | Single run, RGB/RGBW |
| Dimming | Limited, requires dimmable transformer | PWM or 0–10 V, full range |
The low-voltage side is the practical reason neon flex took over. A 24 V run can be installed by a general sign fitter without high-voltage qualifications, it does not need a transformer enclosure at the sign, and the driver can sit in a remote cabinet. For the US market, that also removes a whole category of inspection friction around high-voltage neon circuits under NEC Article 600.
Running cost: it depends on how you run it
At full output the two technologies are closer than the marketing suggests — roughly 5–10 W/m for neon flex against 8–15 W/m for glass neon of similar visual weight. The gap widens for two reasons. First, neon flex can be dimmed to 30–50 % at night, which glass neon cannot do gracefully. Second, a 24-hour glass neon installation burns full power continuously, while a neon flex sign on a timer or photocell draws a fraction of that for most of the day. On a shopfront that runs 14 hours a day, the dimming and scheduling alone usually accounts for a 35–50 % reduction in energy use.
Lifespan and maintenance
Press releases will tell you glass neon lasts 20,000–30,000 hours and LED neon 30,000–50,000 hours. Real-world numbers depend on what fails first. Glass tubes themselves age well, but electrodes sputter and darken, transformers fail, and a single crack kills an entire run — often from a bird strike, a ladder, or thermal cycling on a rooftop. LED neon flex has no fragile parts, but heat is the enemy: a badly heatsinked run at full power will lose output faster than the datasheet claims.
The maintenance difference shows up on multi-site retail. Replacing a section of silicone LED neon tube means cutting and re-terminating one run. Replacing a section of glass neon means a tube bender, a vacuum pump and a return visit.
Brightness, colour and the “glow” question
This is the one place where glass neon still has a real argument, and it is worth being specific about it. Glass neon emits from a diffuse volume of excited gas, so the light appears to come from inside the tube with no visible hot spot. It also reaches saturated deep blue and magenta that phosphor LEDs struggle to match without heavy filtering, which is why some heritage and art installations still specify it.
Modern LED neon has mostly closed the gap. High-density LED pitch inside the jacket plus a milky diffuser removes the dot pattern. RGBW and RGBWW versions solve the weak-white and poor-red problem that plagued early RGB neon, giving a genuine warm white alongside saturated colour. For 95 % of commercial signage the visual difference is invisible at normal viewing distance — and the LED version can produce colours that glass neon physically cannot.
Bending radius and 3D letter work
Every neon flex profile has two bend directions, and getting this wrong is the most common ordering mistake. Horizontal bending (also called flat or side bending) lays the tube in the plane of the sign — what you need for letters viewed face-on. Vertical bending curves the tube out of that plane, for ribbon and contour work. A profile that bends one way will not bend the other.
Minimum bend radius scales with profile size: an 8 × 16 mm profile typically bends to a 30–40 mm radius in the horizontal plane, while larger 20 mm round profiles need 80–100 mm. Deep, tight lettering — a lowercase “e” or a script flourish — needs the smallest profile you can get, which is why side-view silicone neon tube and top-view profiles exist as separate SKUs rather than one “universal” tube.
Outdoor performance and IP ratings
Glass neon outdoors needs water traps, weep holes and careful electrode sealing — a badly made neon sign fills with water and dies within a season. LED neon flex is rated IP67 or IP68, which sounds better than it usually is in practice. The rating applies to the factory-sealed tube, not to your end caps. The seal at the cut end is where these products fail, followed by UV yellowing of cheap PVC jackets in strong sun.
If an installation faces full sun in Florida or southern Spain, specify silicone rather than PVC, and check that the end caps are factory-moulded rather than crimped and glued on site. If the sign faces salt spray within a few hundred metres of the coast, ask for the salt-fog test result, not just the IP number.
Certification: what you actually need
For the US, expect UL or ETL listing for the LED module and the driver, with signs falling under UL 48 and low-voltage lighting systems under UL 2108. Many authorities having jurisdiction will not sign off a permit without a recognised mark, and a CE certificate will not substitute. For the EU, the luminaire falls under EN 60598, the LED module under EN 62031, and RoHS and the ErP ecodesign rules apply as well.
Ask for the certificate plus the test report, and check that the certificate names the exact model you are ordering. A certificate covering a different profile in the same family is not the same thing, and it is the most common documentation gap found in customs audits.
Total installed cost
| Cost line | Glass neon | LED neon flex |
|---|---|---|
| Material per metre | Moderate | Moderate to high |
| Transformer / driver | One per colour circuit | One per run, cheaper |
| Install labour | High — high-voltage, tube bending | Lower — low-voltage, cut and cap |
| Multi-colour | Multiplies every line above | Single run |
| Repair visit | Tube bender required | Swap the section |
| Energy over 5 years | Baseline | Typically 35–50 % lower |
On a single-colour red sign of simple shape, glass neon can still come in cheaper on material and the labour difference may not be decisive. On anything multi-colour, deep-lettered, curved, or installed at height, neon flex wins on total cost of ownership — usually by a wide margin, because every repair on a glass sign is a second visit.
When glass neon is still the right answer
Be honest with your client about the exceptions. Glass neon still makes sense for: conservation and heritage projects where the planning authority requires authentic materials; art installations where the physical depth of the glow is the point; very high ambient temperature environments where LED drivers derate badly; and single-colour, low-volume, simple-outline work where a local tube bender is already on site.
A checklist before ordering neon flex
- Bend direction — horizontal, vertical, or both in separate sections
- Profile size — smallest one that holds your letter radius without kinking
- LED density — higher pitch for tighter radii and dot-free appearance
- Voltage and run length — 24 V for anything over 5 m single-ended
- Jacket material — silicone for UV and heat, PVC only for indoor economy work
- End caps — factory-moulded and potted, not site-glued
- Certification — UL/ETL or CE naming your exact model
- Warranty terms — check whether it covers labour and whether pro-rata applies
We manufacture round silicone neon tube, side-view and top-view profiles, and 40 mm flexible neon for larger architectural work, all in 12 V and 24 V with cut-and-cap accessories. If you are bidding a signage project and want a profile recommendation with the bend radius and power figures for your letter shapes, send us the artwork and we will come back with a specification.