Energizer LED Spotlight Bulb MR16 3.4W Non-Dimmable - Cool White 4000K

This MR16 spot gives 345 lumens from 3.4 watts, which the pack sets against a 35W halogen of the same shape. The cap is GU5.3, the two pin base used on MR16 fittings, so it goes straight into the holder an old halogen came out of. The light is 4,000K cool white: a clean, neutral white with none of the yellow a filament lamp gives, and it leaves the lamp in a 36 degree cone. The body is white with a clear faceted lens across the front.

A 36 degree beam is the general purpose angle for recessed spots: wide enough to cover a worktop from ceiling height, tight enough that the light stays where you aim it. Cool white at 4,000K keeps surfaces and printed detail looking crisp, so it earns its place in a kitchen, a utility room, a home office or a garage. It works for display too, over alcove shelving or a cabinet of glass. If you want a room to feel restful in the evening, a warmer 2,700K or 3,000K lamp is the better choice; 4,000K is a working light.

There is no dimming here. Both the specification and the pack say non dimmable, so wire it to an ordinary switch and keep it off a dimmer circuit, where it can flicker or fail early. The energy rating is E, and the pack prints a 15,000 hour life, which it also gives as 15 years. The IP rating is IP20, so it belongs in dry indoor fittings. Each unit is one boxed bulb, and the minimum order is 12, sold in multiples of 12, which suits relamping a whole ceiling at once. It sits alongside our wider range of LED bulbs in other caps, including GU10 spots and B15 candles.

Will this fit my existing MR16 downlights?

It takes the GU5.3 two pin cap, the low voltage base used on MR16 fittings, which are fed from a transformer or LED driver rather than straight off the mains. Check that your existing supply is the low voltage type before ordering, as the manufacturer does not state a minimum transformer load here.

Can I put it on a dimmer?

No. Both the specification and the retail pack say non dimmable, so it needs a plain on and off switch. Fitting a non dimmable lamp to a dimmer circuit can cause flicker, buzzing and a much shorter life, so take it off the dimmer first.

How bright is 345 lumens in a spot?

Lumens alone undersell a spotlight, because the 36 degree cone concentrates the output into a pool rather than spreading it round the room. The pack sets this against a 35W halogen of the same shape, which is the comparison most people will recognise from an older downlight.

What does 4,000K cool white actually look like?

It is a neutral, slightly crisp white, brighter looking than the 2,700K warm white of a filament lamp and much less yellow. It suits kitchens, workshops and offices, where you want to see colour and detail accurately rather than create a soft evening glow.

Can I mix these with my remaining halogen spots?

They will work on the same circuit, but you will see the difference: halogen sits near 2,700K and reads distinctly yellow beside 4,000K. If the spots are in one visible run, change them all at once so the line of light stays consistent.

How long should it last?

The pack prints a 15,000 hour life and expresses that as 15 years, which assumes a few hours of use each day. Ordering in multiples of 12 makes it easy to keep spares from the same batch, so a later replacement matches the rest.