Decorative Filament Lamps

The decorative filament lamp sits in a different category from a standard LED bulb. Its purpose is as much visual as functional: the glowing filament element inside the glass is part of the fitting's aesthetic, not something to conceal behind a diffuser. This guide covers what to look for when ordering, the fitting types used in Harbro's pendant and chandelier ranges, glass finish choices, and how dimmer compatibility works with LED filament lamps.

What is an LED filament bulb?

A standard LED bulb uses a chip or panel positioned behind a frosted diffuser that produces uniform, directionless white light with no visible source element. An LED filament bulb uses a narrow LED strip arranged to replicate the appearance of a traditional tungsten wire. The strip glows visibly through the clear or smoked glass envelope, producing a warm amber light and a visible structure that becomes part of the fitting's design. The Edison bulb style, which takes its name from the original nineteenth-century incandescent lamp, is the most widely recognised example of the type.

LED filament technology combines the visual warmth of incandescent lighting with the energy efficiency and rated lifespan of modern LED. The filament element draws the same low wattage as a standard LED chip while producing the amber glow associated with traditional lamps.

Wattage, lumens and incandescent replacement

Traditional incandescent lamps in decorative fittings were typically 40W, 60W or 75W. Their LED filament equivalents draw a fraction of that wattage while producing comparable light output. When replacing existing lamps, use the lumen figure in the product listing rather than the wattage to make a like-for-like comparison:

For multi-arm fittings holding six or more lamps, a lower-wattage 2W to 3W filament bulb at 200 lumens per head is usually sufficient: the combined output across all positions is considerable. For single pendants used as the primary light source in a kitchen or dining room, a 6W to 8W lamp will typically be more appropriate.

Cap fittings: E27, E14 and B22

Cap type is determined by the pendant or fitting you are installing into. Confirm the lampholder specification before ordering, as a bulb with the wrong cap cannot be fitted regardless of style or wattage.

• E27 (large Edison screw) is the standard cap for the majority of decorative pendants in the UK, including single-pendant and multi-arm bar fittings. The Melville antique brass pendant and the Ursem multi-light bar from the Inspired Lighting range both use E27. The widest selection of filament shapes and glass finishes is available in this cap size.
• E14 (small Edison screw) is the smaller format used in multi-arm chandeliers and candelabra-style fittings where multiple lamps are visible simultaneously. Candle (C35) and small globe forms are the most common E14 filament shapes.
• B22 (bayonet cap) is the standard UK domestic fitting. Decorative filament bulbs with a B22 cap offer the same warm vintage aesthetic in a format compatible with the widest range of UK ceiling roses and standard lamp holders.

Colour temperature for decorative filament lamps

Filament bulbs are almost exclusively available in warm and extra-warm colour temperatures, which is consistent with their decorative and atmospheric purpose. Colour temperature is measured in Kelvin (K):

• 2200K (extra warm white) produces a deep amber, candle-like light. This temperature closely matches the original incandescent filament and is the defining characteristic of the Edison bulb aesthetic. Well suited to period-influenced interiors, bar and restaurant settings, and any application where atmosphere takes priority over task illumination.
• 2700K (warm white) is the closest match to a standard halogen lamp and the default choice for living rooms, dining rooms and bedroom pendant lighting. This temperature sits in a comfortable middle ground: warm enough to feel residential, bright enough to function as a primary light source.

Avoid mixing colour temperatures within the same fitting or across fittings in the same open-plan space. The difference between 2200K and 2700K is clearly visible in use and inconsistency will be noticeable.

Glass finish and filament shape

Glass finish and filament arrangement define the visual character of a decorative lamp in equal measure. The two choices interact: a squirrel cage filament in smoked glass produces a very different effect from the same filament in clear glass.

• Clear glass puts the glowing filament on full display, making the lamp itself part of the fitting's visual design. Best suited to open-shade pendants and exposed lampholder fittings where the lamp is intended to be seen.
• Smoked glass uses a dark-tinted glass envelope to soften the visible filament, reducing the direct intensity of the glow and producing a richer, more intimate ambient light. Well suited to antique brass, aged bronze and dark metallic finishes. Note that light output from a smoked glass model is lower than an equivalent clear glass model at the same wattage.

The main filament shapes available in this collection are as follows. Exact stock availability by shape and cap should be confirmed from the product listings above:

Dimmable LED filament bulbs

Not all filament bulbs in this collection are dimmable, and fitting a non-dimmable LED to a dimmer circuit causes flicker, premature driver failure and occasionally audible buzzing. Every dimmable model in the range is marked as dimmable in its product specification. When specifying a dimmable installation, the dimmer switch itself also matters.

Trailing-edge (electronic) dimmers are broadly compatible with LED loads and are the recommended choice for filament lamp circuits. Leading-edge (phase-cut) dimmers were designed for tungsten halogen loads and frequently misbehave with low-wattage LED drivers: flickering at low brightness levels and incomplete shutoff are common symptoms. If you are replacing incandescent or halogen lamps that were previously on a leading-edge rotary dimmer, a dimmer replacement at the same time as the lamp upgrade is strongly advisable. If a dimmable filament bulb on a compatible trailing-edge dimmer still flickers at low settings, adjusting the dimmer’s minimum-load trim resolves the issue in most cases.

Pendant fittings compatible with decorative filament lamps

A filament bulb performs its full visual role only in a fitting that exposes the lamp. Enclosed shades and frosted diffusers conceal the filament and defeat the purpose of the lamp style. The pendant and chandelier ranges below are available through Harbro and take E27 or E14 filament bulbs directly:

Why buy decorative filament bulbs from Harbro Electrical?

Harbro Electrical is an independent trade wholesaler established in 1994 and based at our 10,000 sq ft warehouse and showroom at 5 and 6 Whitworth Road, Peterlee, County Durham SR8 2LY. We carry over £500,000 of stock and supply electricians, contractors and facilities teams across the North East and the UK. Decorative filament lamps are a consistent seller across our pendant, chandelier and decorative lighting ranges, which means reliable stock depth, competitive trade pricing, and a team that understands how these products are specified and installed on site.