Watts a Lumen ??

Ey up my faithful blogworms, What's (Watts) a Lumen ??

You may well ask ...... I thought it was worth following up on my COB lighting blog with an attempt to clear up some of the pure gooble-de-gook that's written on the side of light bulb boxes

You will see all sorts of rubbish written on the side of LED light bulb boxes, how the hell do you figure out which bulb it is that you need for your lights at home......

 1)  Right, lets start with Energy ratings, if you're looking at Gu10 bulbs in your ceiling like the ones shown in the pics, you're normally these days looking at LED's to save energy and money.
Fact: All LED lights save energy because they're low wattage, you've got to be a 'muppet' not to realise that 5 watts burns less energy than 50 watts !. So largely you can ignore the energy rating cos that's common to them all.

 2) Next: the wattage, this does not  tell you how bright they are, it used to with the old tungsten lights but it doesn't really help any more. The wattage simply tells you how much energy you will be using when you switch them on.
Believe it or not, a 4w, 4.5w, 5w, 6w, 7w & 8w can all give the same light output !! ..... "Give me a break!" I hear you say, how on earth can that be possible ?? I'll explain in a minute.



 3) Hours rating for bulb life:  generally a total bloody guess, if it says 50,000 hours on a bulb packet. 50,000 hours at 8 hours a day is 17.12 years, how the hell did they test that ?? The main factor, as I understand it that governs bulb life is heat ie: how hot a bulb gets while it's switched on.
The cooler the bulb runs, the longer it lasts and the less energy  you lose to heat. So then, 50,000 hours is no real judge of the reliability and longevity of a bulb. The only way to ensure you get a good lifespan on a bulb is to buy known and reputable brands, you buy cheap imports they will blow in no time at all and you've only got yourselves to blame for buying rubbish in the first place !! Remember: Buy cheap, buy twice, there's a reason they're cheap !! TIP: avoid Chinese writing on the box !

4) The next piece of info you get is something that says 2600K, 3000K, 4000K or whatever. This info can actually be useful in your bulb selection cos it tells you how warm or cool the light is. Generally 2800K to 3200K is accepted as a 'warm' white light and 4000K as a 'cool' white light. 
As a rule of thumb, the number gets smaller it gets warmer and higher it gets cooler. This can help you choose how the overall atmosphere in the room looks.


5) This is where we get to the really important bit ....... How much light am I going to get out of the bulb ??.
OK, this is where Lumens comes into it, Lumens are the amount of light output you get from any given bulb. Simply put, the higher the number, the more light you get out of it.

You will see in the pic, left, 110 Lumens ( poor output) the one above 160 Lumens ( better but still hopeless), the energy smart one at the top of the blog 200 Lumens ( getting better but you'd still need a lot of them in your ceiling to light a room up !!)

Now compare these to the COB lights I talked about previously where Cob light output is 400 Lumens for warm white and 430 Lumens for cool white and you really begin to realise that when you're looking for new bulbs to give a good light, change you're thinking and look for the Lumens rating. Nowadays you simply cannot rely on wattage figures like you used to !

If you've not read my blog about COB yet, then read "COB but no corn" from my list, a lot more of this weeks blog will make sense.

I hope this has helped you to re-think how you look at buying your bulbs and gone someway towards explaining what to look for and what to ignore on the box.

Your faithful servant, as ever. Jules