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.
V-TAC R39 Reflector Spot Light - 3W, 250lm, 6400K
3W LED reflector bulb, E14, 250lm, 6400K, IP20
Philips Master PL-S - 7W/840 4Pin 2G7 4000K Cool White
Philips Master PL-S 7W 2G7 compact fluorescent cool white lamp
Netlighting LED Filament GLS Lamp - 8.5W 2700K 1055lm B22 Dimmable Frosted
8.5W LED filament GLS lamp, 2700K, 1055lm, B22, dimmable, frosted.
Wessex LED Frosted Dimmable Mini Globe Bulb Lamps - 3.4W BC Cool White 470lm 4 P…
Dimmable 3.4W LED frosted mini globe bulbs, BC cap, cool white, 4-pack.
Knightsbridge LED Corn Lamp - 18W 4000K 2495lm E27 non-dimmable
18W LED corn lamp with E27 cap, 2495 lumens, 4000K cool white, non-dimmable.
Saxby LED SMD Lamp - 2W 4000K 200lm G9 Non-dimmable
2W G9 LED cool white lamp, 200lm, frosted polycarbonate, non-dimmable
V-TAC 4W A60 Filament Bulb with Samsung Chip - B22 clear cover, 3000K
4W A60 LED filament bulb with Samsung chip, B22, 3000K
Crompton Energy Saving 4-Pin BLD Light Bulb - 18W
18W energy saving 4-pin BLD light bulb, dimmable
Bell Clear Tungsten Halogen Lamp - 120W R7S 2700K Extra Warm White
120W R7s clear halogen lamp, 2700K extra warm white, 2250 lumens.
Kosnic GOLF - 4.9W E14 2700K
Kosnic GOLF 4.9W E14 LED bulb, 2700K warm white, energy saving
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.














