Next we have LED lighting – after compact fluorescent – after halogen – after incandescent.

Following are some of my thoughts on lighting. Any experts or professionals who disagree, feel free to comment, but you are wrong.

Incandescent and Halogen

Incandescent worked but was not very efficient in that a lot of the power went into heat. Back then the lamp hung down from the ceiling and you got to use all of the light produced; unless you chose to put some stupid lamp shade on it. You also got to keep the heat produced in the room, so on a cold day it was probably close to 100% efficient.

Halogen was just a bad idea right from the start. They produce as much, if not more heat than incandescent and most of the lamps and fittings squirt what light they do produce in one narrow direction. Most of the heat went up though the silly light fitting into the roof space where it was actually a safety hazard if the fittings were not installed to cope. The solution was to install lots of fittings; 4 or 6 or 8 – 50 watt lamps in a room that once had a nice bright 100 watt incandescent. But that was what the “expert” lighting designer told everyone was the best thing to do. You had 200 or 400 watts of light replacing a 100 watt light – progress at last.

Compact fluorescent lamps (CFL) took a while to get going but are currently a leader. The original claims of 15W being equal to a 100W incandescent were exaggerated, but the light output has now improved. The CFL is functionally a better replacement for a incandescent, not so much a halogen. A 20W CFL hanging clear in the middle of the room is very similar to a 100W incandescent. Put the CFL in a modern recessed light fitting and you are wasting half of the light produced. If you ignore the mercury content and premature electronic driver failures and leave the lamps exposed, they do well.

Warm white and cool white. I hate warm white because I want as much light as possible from the watts to see what I’m doing. They should be called dim yellow lights. But for some reason there are far more “dim-yellow” lights available than the brighter cool white variety. This applies to LEDs and fluorescents.

LED lighting

LED lamps are currently where CFLs started out; expensive and/or not bright enough. This will improve as volumes increase and prices drop.

LED light output is deceptively rated. A LED due to it’s construction naturally sends the light in one direction, unlike a incandescent that send it in all directions. If you measure the light level at one point in front of the LED it will be as bright or brighter than the incandescent. But the total amount of light produced is much less because it’s only lighting one small area at a time. Therefore you need a lot more LED lamps to achieve the same overall lighting effect.

Because LEDs are relatively efficient you can have lots of them (wallet permitting) and still use less power than the incandescent and slightly less than the CFL. A true 5 Watt LED does get very hot and would destroy itself without a heatsink. If a current generation LED lamp doesn’t run quite warm with a heatsink, then it’s a toy.

Running costs

Our local paper (Upper Hutt Leader 4-4-12 pg-27) had a article stating that a LED light is so efficient that it can last up to 50 years. That just means it’s long-term reliable; nothing to do with efficiency. They also say that a $1 incandescent costs $25/year to run and a $8 CFL costs $5/yr. Power currently costs about $0.25 per unit (KWh). Lets assume 6 hours a day, every day average; that’s 2190 hours per year.

• Incandescent 100W (cost $2 & lasts 1 year) = 219 units = $56.75
• CFL 20W (cost $6 & lasts 3 years) = 43.8 units = $12.95
• LED 10W (cost $30 & lasts 10+ years) = 21.9 units = $8.48

The total cost is per year and includes the cost of the lamp. I’ve assumed 10W of LED = 20W of CFL; a pretty good LED light.

So there is a big saving in using CFL rather than incandescent and a smaller saving with LED if you can afford the initial high cost of LED.

As for the electricity suppliers who say that it doesn’t cost 25 cents per unit… bull crap. Once you add daily line charges and tax it does cost that much. (early 2012, NZ$)

It’s a bit like solar electric panels; good in theory but not ready yet – that’s a rant for another time.

Update

I bought some cheap 3W LED lamps on Trade-Me to try out; about $7 ea. Each had about 48 LEDs and went into a ES mains fitting. The light output was pretty pathetic and dropped off after a very short time.

Eventually I pulled a couple apart and replaced the LEDs, one with white and one with yellow. I didn’t have enough white LEDs to do two. The white one is now useful, although not bright and the yellow one is not much use but looks nice.

I’ve also noted CFL failures here.