Osram LED Lamp | Base: E14 | Cool White | 4000 K | 4 W | Replacement for 40 W | LED Retrofit CLASSIC B, Double-Pack, [Energy Class E]

Great product fits perfectly and has a nice white/warm colour to it came in perfect condition

I received the 2.5W cool white 4,000K version for review. It’s a very good compromise between warm and daylight white – just right for reading or task lighting, without any tendency towards blue. We’ve used it in a bedside light. It does seem as bright as a 25W incandescent. The CRI of 80 isn’t the best but is fine for most purposes.This is made in China, just like nearly all the LED bulbs you’ll find. I feel, though, that with a western brand I can at least trust the specs. Osram doesn’t seem to be suggesting unrealistic lifetime or exaggerating the CRI. I’m very happy with this and would buy again.

LED's have very much become the standard for light bulbs over the last couple of years and for good reason too - they are so much cheaper to run than conventional bulbs and last so much longer too. For example, this bulb uses 2.5W of power and has a stated light output of 250 lumens. To achieve a similar light output from a tungsten bulb, you would need a bulb with a power rating of 17W. As such, this bulb will save 14.5W of power for every hour of runtime.If it is assumed that electricity costs about 18p per unit (kW/h), this means that this LED bulb will save about 0.26p for every hour it is used. Whilst this might seem tiny, it very quickly mounts up i.e. £2.61 over the course of a year (assuming 1000 hours of use per year), at which rate, the bulb should last 15 years. Accordingly, the initial investment of this bulb should be very quickly recouped and very quickly provide significant savings.As mentioned, this bulb is equivalent to a 17W tungsten bulb and as such, it is quite dim, probably only suitable for ambient lighting. It is also quite similar in size to its tungsten equivalent (3.5cm in diameter x 10.0cm in length) and as such, it should be suitable as a like for like replacement in most circumstances.One consideration which is relevant to LED bulbs which wouldn't have been relevant to tungsten bulbs is the colour temperature. There are broadly three main colour temperatures which LED bulbs are produced in, these being 2700K (warm white), 4000K (cool white) and 6500K (daylight white). This particular bulb has a colour temperature of 4000K (warm white) and personally, this is slightly cooler than I would like but still perfectly acceptable.Whilst in use, the bulb remains reasonably cool to the touch and given that heat is probably the biggest cause of premature failure in LEDs, this provides reasonably confidence that the 15,000 hour lifespan should be achievable. Clearly, this is not something which I can confirm as yet (otherwise my review wouldn't be available for quite a number of years).As a final point, the title of this product makes reference to this bulb as having a colour temperature of 2700K (rather than 4000K). Whilst a version of the bulb may be available with this characteristic, it is incorrect for the version of the bulb which I have received. Accordingly, make sure you chose the correct option on the Amazon product page, to avoid getting a bulb which is different than expected.

This was really poorly packaged and arrived completely damaged and unusable. Really disappointing.

I am a big fan of LED and the whole house is now converted to one kind or another. It's a no-brainer, really. Energy consumption is low and the light they give off (and instantly) is massively superior to the old "energy-saving" bulbs that for a time it looked like would condemn us all to a life lived in twilight. This build doesn't disappoint on those fronts. It looks well made not too heavy and looks quite attractive with its two-pronged appearance. I am a little unsure about the description "warm white", though. I have put it in a fitting with two other bulbs, from another manufacturer and alongside their slightly orangey warmness, this bulb looks much, well, whiter...almost a blue light.That said, I'm happy with it and I'm looking forward to not having to replace it for a good few years.

The product is non-dimable whereas the product it claims to replace offered this feature. This difference is not made clear in the advertised specification.

The bulb is quite a cold white light, it’s not very warm in my opinion. However it is a lot more energy efficient which I like and supposed to lay for years so we will see! I wasn’t to pleased with its protective packaging, there wasn’t much. It was just the bulb box inside a cardboard envelope but luckily the bulb works fine as far as I can see. No issues with the bulb!