When you’re choosing light bulbs, start with the fitting, the output you need, and whether the lamp is on a dimmer. GU10, E27, E14 and bayonet light bulbs all do the same job, but the wrong cap or a non-dimmable lamp bulb is where the call-backs start. LED light bulbs are usually the first swap for most replacements. Filament or decorative versions make more sense where the fitting is on show and the look matters.
Knightsbridge LED Lamp - 4W 4000K 430lm G9 dimmable clear
4W cool white G9 LED lamp, dimmable, 430 lumens
Ali Industries LED BA9 Bayonet - 10mm x 23mm 24V green 1 chip LED
BA9 bayonet LED bulb, 24V green, 10x23mm, long life 30,000h.
Integral LED GLS Dusk till Dawn Sensor - 5W 470lm BC (B22d)
Integral LED 5W BC bulb with dusk till dawn sensor, 470lm warm white
Ali Industries LED BA9 Bayonet - 10mm x 23mm White 230V 4 chip
White LED BA9 bayonet bulb, 230V, 10x23mm
Lighthouse CFL Spiral Lamp - Daylight H125 x W48mm BC B22 15W 6500K
Lighthouse 15W CFL spiral daylight lamp, BC B22 cap
Tungsram Fluorescent Bulb - 26W 105V GX24q-3 4-Pin Hex Plug-in Dimmable 1800lm
Dimmable 26W CFL bulb, GX24q-3 base, 1800lm, 105V
Luxna LED Glass SMD Lamp - 4.5W 4000K 440lm GU10 Non-dimmable
4.5W GU10 LED lamp, 4000K neutral white, 440lm, non-dimmable
Goodwin Capsule G9 LED Lamp - 4.5W/40W 470lm 300D RA90 6500K Dimmable Clear
4.5W G9 LED lamp, 470lm, 6500K daylight, dimmable, clear.
Goodwin Classic GLS LED Lamp - B22D 6.5W/60W 806lm Clear 2700K RA80 300D Dimmabl…
6.5W (60W equivalent) dimmable LED GLS lamp, B22 cap, 806lm, 2700K
Netlighting Pygmy Incandescent Bulb - 15W E14
15W pygmy incandescent bulb, E14 base, dimmable
Start with the space you’ve got and how the lamp will be used, then narrow the light bulbs from there. A tight fitting or shallow shade rules out some shapes straight away. A dimmer changes the choice again, because not every lamp bulb behaves well at low output. Most call-backs come from the wrong cap or a bulb that looks right on paper but sits awkwardly in the fitting. If you’re replacing like for like, keep the cap and size consistent first, then decide whether you want a standard LED, a dimmable option, or a more decorative finish.
For most jobs, you narrow light bulbs by format before anything else. LED light bulbs are the usual pick when you want lower running cost and less heat, but the lamp still has to suit the bulb, and any dimming gear needs checking.
Bayonet light bulbs still make sense when you’re swapping like for like and want the same cap back in without changing the holder. Screw light bulbs, including e27 light bulbs and e14 light bulbs, cover the same sort of replacement work. E27 suits larger general-purpose fittings. E14 is more common in smaller decorative lamps. GU10 light bulbs are the one you reach for when the fitting takes a mains spotlight lamp, though the wrong type is less forgiving once it’s in hand.
The first check is the fitting and the lamp body around it. That tells you if you’re buying a straight replacement or changing the look of the job.
After that, check whether it needs to dim cleanly and whether LED light bulbs make sense for the running cost. A cheap swap that flickers on a dimmer gets called back.
Shape matters too. A shallow shade or tight lantern usually rules out the bulkier options. Decorative lamp bulbs are picked more for the finish than the output.
If the job is moving away from lamps altogether, Downlights are the next call. If you only need the light to come on when someone’s there, Motion Sensors may be the better buy.
Once you’ve settled the bulb spec, the next call is usually the gear around it - the fitting, any trim or screen, and whether the lamp needs a matching control or sensor. That keeps a simple replacement from turning into a second visit.
A lot of call-backs come from mixing the wrong bulb with the wrong fitting, or leaving the control side unresolved. If the job includes downlights or a timed circuit, sort those parts with the light bulbs so you’re not back chasing compatibility after the fact.














