GU10 CFL's - 2700K V's 4000K

[GaryMo]

Has anybody any experience of using both 2700K and 4000K GU10 CFL's?
I'm ordering 11 x 7watt 2700K lamps for my bedroom due to them being giving a warmer light but not too sure what to order for an en-suite. There will be 4 fittings, probably go for 11watt but not too sure how 4000K will look. Would they produce a noticeably crisper, whiter light?

 

[tim west]

compared to your bedroom yes, sure you want to be confronted by such a contrast in lighting when visiting the loo during the night?

 

[GaryMo]

compared to your bedroom yes, sure you want to be confronted by such a contrast in lighting when visiting the loo during the night?

lol, that's my argument against but in reality I wouldn't be switching the bedroom lights on unless I had a death wish
Think I'll go for matching 2700K though. Thanks

 

[Steve]

Gary, I'd fit some LED lights too in between the CFLs. The CFLs take a good 4-5 mins to reach full brightness and you want something to give light in this time. Also 11 CFLs may be too bright when they do reach full brightness, so interspersing a few LEDs wont hurt anything.

 

[Stoday]

Would they produce a noticeably crisper, whiter light?

No. It'll be a very much colder light that will clash with the 2700 degK lamps. A 500 degK difference in adjacent rooms is quite significant.

 

[viewer]

As a test for a new kitchen we recently set up a number of comparisons. Room uses 10 downlights fixed GU10s.

Rough results:-

LEDs great and best light, but to be big enough for the job were £30 each!
Smaller ones good for bedrooms, bathrooms and study. Light colour good.

7W Megaman from TLC very yellowish and gave the feeling of dim rather than warm.

9W as above much better but a bit butterish.

11W as above very good, bright and still warm. Very attractive. These are roughly equivalent to 50W halogens.

Settled on 11W and very pleased.

As stated by supplier these are longer than halogens so stick out of fitting if the "fixed-roof" type of fitting is used. (Longer legs can be put on easily)
No problem if using fitting which holds bulb via a spring (such as Screwfix adjustable type). May be important en-suite.
In bathroom we have 2 11W plus 5 No 1.5W LEDs. The LEDs give a blueish effect to the ceramics, but are attractive. As Steve says, the 11W s are slow to full brightness, but this may not be a problem as with a bathroom, how much light you need varies according to how long you spend in there.
The biggest problem with downlights is that they can have a distinct spot effect so you need to be getting a good cover to avoid the "beam me up Scotty" effect which can be a problem for shaving, make-up etc.
HTH
V

 

[Stoday]

The power rating has nothing whatsoever to do with the colour of the light.

You can't say that because one 11W lamp has a buttery colour, another will, even of the same make. It all depends on the phosphor used in the lamp.

Trouble is, most retailers don't understand colour temperature so it's pot luck what colour you get. Buying off the internet is better because some do give you a choice of colour.

For a dwelling, I would suggest keeping below 3500 deg K otherwise the light will look far too cold.

 

[Space cat]

If you want to know what a particular colour temperature will look like you can use filament lamps as a guide. Their colour temperature is their real temperature!

A standard filament bulb is about 2800K. This is a very yellow light. You might not notice this but a camera certainly will. Try taking a colour photo of a room with a filament lamp in it through the window just as daylight is fading. Include plenty of the outside scenery in the frame. See how orange that bulb is! (This is something to consider when choosing paint colours. )

Halogens run hotter - up to 3400K - so their light is whiter but still distinctly yellow. Fluorescents can be made in a wide range of colours up to and including UV by changing the phosphors inside the tube. Most have a strong green tinge that we don't notice but film does. Sunlight is about 6000K.