Questions on LED

oldwiring

Q 1.
I have a 4 spotlight fitting in the kitchen. Can I replace the existing bulbs with LED ones, as each fails, or must I replace all at same time?

Q 2

I have seen LED bulbs rated 25 lumens, all Cool White and same fitting, but some say 4w and others 3w.
Would I perceive any difference in the output and quality of each?
Why would the maker make different claims?

Gerry1

A2. You'll see 806lm bulbs rated at 100W and 6W. The latter are more efficient because they're LEDs. LEDs also vary in efficiency e.g. depending on their drive circuitry. If they're 25lm they're 25lm so they should look the same.

However, you might want to think twice about Cool White because that gives a very harsh industrial appearance, but that comes down to personal preferences.

One thing seldom mentioned is that LEDs can ruin radio reception, both analogue and digital. Sadly the only way to find out is by trial and error, and the purchase price is seldom a guide.

Talldave

You can replace bulbs one at a time, but you'll probably have a mismatch in colour temperature (how yellow or white/blue the light looks) that may look weird. And similarly if you don't buy the new bulbs at the same time, they may not match.

oldwiring

Gerry1 wrote: »

A2. You'll see 806lm bulbs rated at 100W and 6W. The latter are more efficient because they're LEDs. LEDs also vary in efficiency e.g. depending on their drive circuitry. If they're 25lm they're 25lm so they should look the same.

However, you might want to think twice about Cool White because that gives a very harsh industrial appearance, but that comes down to personal preferences.

One thing seldom mentioned is that LEDs can ruin radio reception, both analogue and digital. Sadly the only way to find out is by trial and error, and the purchase price is seldom a guide.

I'm using cool white in a warm white ex-halogen standard lamp, which had a warm white bulb. I seem to be able to focus better, when reading.

As tp radio, we have new bedhead light, bulbs from Sainsburys, and the digital radio is very close. Perfect sound!

victor2

I replaced 9 halogen spotlights in our kitchen with 9 LED spots (and added two more pendant lights as well) all at once, rated at 4W cool white. We deliberately chose cool white (about 6000K) as we wanted a daylight look in a kitchen with not much natural light in it. The lights tend to be on even during the day, so the reduced power consumption was significant.
As Talldave says, it is better to buy them all at once to get the same colour, and they're reasonably cheap these days, so won't break the bank. Don't buy off "a well known auction site". They'll come from China, won't be the same colour and won't last long IME. Even if buying from more reputable suppliers, don't believe the stated life of 10 years, 10,000 hours or whatever huge number they quote. In my experience, they last nothing like that. Nearly all our house has LED bulbs and they usually last 2-3 years at best.
We've ended up with mostly 5W LED bulbs in our kitchen now and try to go for "wide beam angle" bulbs to get good coverage. Many different types, as they keep improving the technology, but all cool white.
I always buy two or three when I need some, so I can replace a few bulbs and keep the old working one(s) as spares.

Gerry1

victor2 wrote: »

Even if buying from more reputable suppliers, don't believe the stated life of 10 years, 10,000 hours or whatever huge number they quote. In my experience, they last nothing like that. Nearly all our house has LED bulbs and they usually last 2-3 years at best.

The 11W Osram GLS LED bulb I obtained on 24 Sep 19 flickered and died tonight. It was a replacement for one bought earlier in the year that had also failed. It was in the kitchen, not even a porch light.

It seems that the claimed life is reduced by about a factor of five if it's used cap upwards, and the same again if it's a semi-enclosed or enclosed fitting.

victor2

Gerry1 wrote: »

...
It seems that the claimed life is reduced by about a factor of five if it's used cap upwards, and the same again if it's a semi-enclosed or enclosed fitting.

Actually switching them on seems to dramatically reduce the claimed life too. :rotfl:

[Deleted User]

i replaced my 8 ( 2 x 4 pendents lights ) with 8 x 5watt LED s..meaning all 8 on are only 40 watts..I used small screw adapters a few years ago because finding the bayonet fitting was difficult.. Its not now.
Please do not buy your LED s from any Ebay source from China, only from recognised sellers like Screwfix..
Cool white are fine for kitchens and bathrooms but warm white needed for lounges and bedrooms ..
Personally I would nt go for anything less than 5 watt LED s

Cardew

oldwiring wrote: »

Q 1.
I have a 4 spotlight fitting in the kitchen. Can I replace the existing bulbs with LED ones, as each fails, or must I replace all at same time?

https://www.lightbulbs-direct.com/article/replacing-12v-halogen-mr16s-with-leds/

GunJack

re: the cool white/warm white thing....we've got 4x 5W cool white spots in the kitchen (to replace 4x 50W halogens) and it's far better for cooking/food prep, whereas we've got warm white in the lounge which we find better for loungy-type activities

Try both if you don't mind a few quid extra, and see which suits you best. Oh, and Home Bargains do a pretty good range of LED bulbs at reasonable prices.

Talldave

I'm currently replacing halogens in the kitchen with 3000K LEDs - my first attempt with 2700K was too "orangey" and it turns out the halogen themselves claim to be 2950K. But as they're AR111s it's an expensive project and there's a frustrating range of wattage, colour temperature and beam angle to dabble with. Since I've stuck to Philips bulbs I've never had to replace one.