CFL v Halogen capsule

[John]

I have wanted to be energy efficient and had replaced the candle bulbs with CFL having also tried LED. The CFL is 9W and isn't bad. Today I bought a 42W halogen capsule version to see how that performed.

At first I thought "wow" because it was so much brighter but then the CFL warmed up (ok so it took over 4 minutes) and it is now pretty much neck and neck. I would say the halogen is about 5% brighter and the light is a bit sharper but it does use 4 times the power. Humm, think the CFL will go back in tomorrow.

[Andrew Gabriel]

I normally quote a 1:4 power ratio between CFL and filament for equivalent light output. There are several things that can affect this quite dramatically though.

Yes.

If there was some reason you really wanted halogen, then 12V is much more efficient than mains, but still not up there with CFL.

[John Rumm]

Tests made by looking at the light are often rather inaccurate. I have a three lamp fitting in my hall with two ultra compact candle CFL lamps and one 40W incandescent. Looking at the lamps they all look similar in brightness. However when the conventional lamp fails you really notice it. Sticking a light meter under it you realise you get 36 lux from the three, but with just the two cfls you are down to 14 lux!