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.
Integral R63 LED Bulb - 9.5W E27 3000K 700 lumens 54W equivalent 80CRI 120°
9.5W R63 LED bulb, E27, 700 lumens, 3000K warm white, 54W equivalent
Megaman 4.2W LED GU10 PAR16 - Warm White
Non-dimmable 4.2W LED GU10 lamp, warm white, 410 lumens, replaces 35W halogen
Knightsbridge LED Lamp - 4W 2700K 390lm G9 Dimmable Clear
4W LED lamp, 2700K warm white, 390lm, G9, dimmable, clear
Luceco 4-Pin DD LED Light Bulb - 18W 2000lm 4000K Electronic
18W LED bulb, 2000lm, 4000K, for 4-pin magnetic ballast
All LED GLS B22D - 9W
9W dimmable LED GLS lamp with BC (B22) cap
Bell 4W BC Filament Golf Bulb
4W filament golf ball bulb with BC bayonet cap
Forum Large Decorative Lamps - 6W 2000K
Forum 6W LED large decorative filament lamp, 2000K, E27
ALI Industries LED BA9 Bayonet - 10mm x 23mm Red 230V 2 Chip
Red LED BA9 bayonet lamp, 10x23mm, 230V.
Integral LED GU5.3 - 8.3W
8.3W dimmable LED MR16 lamp, GU5.3 cap, 36° beam
Status Filament LED Light Bulb - 5.5W B/C round daylight single
5.5W BC round daylight filament LED bulb with visible filament
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.














