Incandescent vs. compact fluorescent vs. LEDs vs. halogen
In 1996, I worked at an environmental foundation on the coast of Maine that was an early adopter of compact fluorescent bulbs. At the time, they were expensive, and they flickered when you turned them on. After a long winter of getting flickered at every time I turned on the light, I started avoiding compact fluorescent bulbs.
Last week, one of my energy-zealot friends gave me a 1200 lumen compact fluorescent bulb after I commented on how quickly her CF lamp turned on.
I now have the 1200 lumen CF bulb in one of the overhead lights in my house. There is an identical lamp on the same circuit that still has an incandescent bulb rated at 1280 lumens. Both lamps have glass enclosures around them, so this is not the strongest argument, but neither my friend Aaron nor I can tell the difference between the two lamps– same brightness, same color, no flickering, and no buzzing. The CF does seem slightly dimmer for the first 30 seconds after a cold start, and I have been able to hear buzzing when the CF bulb is in an open socket less than six inches from my ear. These are the most minor of objections– overall, my previous opposition to CF bulbs is now gone.
Now that I work at a renewable energy engineering company, I’ve been looking at the options more closely. Below the costs compared for the bulbs I have in my house. Compact fluorescent is the clear winner. In my calculations below, I assume electricity costs of $0.20/kWh, which is what I pay in Massachusetts, but CF’s now beat incandescent even with free electricity.
Incandescent (GE Reveal 100, #48690)
Cost for bulb: 1280 lumens, $1.25 ea. in qty. 4, 750 hours, 100 W: $0.014/lumen-year
Cost for power: (0.100 kW * 24 hours * 365.25 days * $0.20/kWh / 1280 lumens ) = $0.137/lumen-year
Total cost: $0.151/lumen-year
Compact fluorescent (Maxlite Micromax Spiral MLM20S)
Cost for bulb: 1200 lumens, ~$6 ea. in qty. 1, 10000 hours, 20 W: $0.004/lumen-year
Cost for power: (0.020 kW * 24 hours * 365.25 days * $0.20/kWh / 1200 lumens ) = $0.029/lumen-year
Total cost: $0.033/lumen-year
Out of curiosity, I decided to compare a halogen bulb from the drugstore down the street and an LED bulb I found on the global netweb to the bulbs I have. The LED bulb is almost competitive with the CF on cost, but it only produces 60 lumens, so you’d need 20 of them to light a room, which would cost $500. They would last for eternity, but I think I’ll wait a few years for the cost to drop before I buy those.
Halogen
Cost for bulb: 830 lumens, $7 ea. in qty. 1, 2000 hours, 50 W: $0.037/lumen-year
Cost for power: (0.050 kW * 24 hours * 365.25 days * $0.20/kWh / 830 lumens ) = $0.106/lumen-year
Total cost: $0.143/lumen-year
LED (CC Vivid Plus)
Cost for bulb: 60 lumens, $25 in qty. 1 (on sale, even!), 60000 hours, 1.3 W: $0.061/lumen-year
Cost for power: (0.0013 kw * 24 hours * 365.25 days * $0.20/kWh / 60 lumens ) = $0.038/lumen-year
Total cost: $0.099/lumen-year
January 1st, 2007 at 4:06 pm
Nice work. Now what if you buy power company subsidized CF bulbs for $0.33 each in Northborough, MA?
January 20th, 2007 at 9:28 am
It is amazing how much cheaper and better the new CF bulbs are compared to those made even four years ago. This is particularly interesting to me now as I am learning about lighting in my architectural curriculum at the moment.
Also: Given that incandescent bulbs are efficient heaters that happen to give off light why not use them in the northeast winter?
January 21st, 2007 at 9:00 am
Hi Alex,
I’ve thought about the lightbulbs-as-heaters. In Massachusetts, where my bulbs are located, electricity is about 4 times as expensive (0.20 $/kWh) as natural gas per joule delivered to my house. Even if the bulb emitted all of that energy as heat (which is close to true, though a little energy escapes as light through the windows), our gas boiler is more than 25% efficient.
In a place where electricity is cheap and natural gas is expensive (Canada– lots of hydro?), incandescents might be a more economical solution. I don’t know much about the environmental impacts of natural gas collection and delivery as compared to electricity.
January 31st, 2007 at 9:31 am
I read your article on round cube, and it seems you’ve succesfully installed it.. This is hardly the place to ask a question, but I’d appreciate it if you answered.
I haven’t been able to log-in successfully. To help diagnose where I went wrong let me show you the changes to the main.inc.php, and the db.inc.php.
For the db.inc.php (no .dist i removed that)
mysql://user:pass@mysqldatabasesubdomain.krusnix.com/databasename
For main.inc.php
$rcmail_config['default_host'] = ‘mail.krusnix.com’;
// TCP port used for IMAP connections
$rcmail_config['default_port'] = 38;
–
$rcmail_config['smtp_server'] = ‘mail.krusnix.com’;
// SMTP port (default is 25; 465 for SSL)
$rcmail_config['smtp_port'] = 63;
// SMTP username (if required) if you use %u as the username RoundCube
// will use the current username for login
$rcmail_config['smtp_user'] = ‘%u’;
// SMTP password (if required) if you use %p as the password RoundCube
// will use the current user’s password for login
$rcmail_config['smtp_pass'] = ‘%p’;
So those are all the changes I made for the actual file.
I headed over to the roundcubedatabase phpinfo site, and imported the initial mysql file. Then I clicked users, clicked insert then left the function blank and for value added krusnix@krusnix.com for mail host I yet again left the function blank and added mail.krusnix.com, for alias I just put krusnix. Then I clicked go.
*note that I have a krusnix@krusnix.com email already set-up at the dreamhost cpanel. So when I head over to the roundcube url, and enter krusnix@krusnix.com and the password set at the dreamhost cpanel it says my log-in is incorrect, it does the same thing when I just leave it at krusnix, and enter the same pass as above.
Any help would be appreciated.
March 3rd, 2007 at 10:41 am
[...] I was surfing around trying to find out what the relative cost of various lighting types is to determine if paying for LED lighting would be worth it. I ran across this posting, which does a nice job of comparing the various types. It’s still pretty up to date (Dec. 30, 2006), but it’d be interesting to track this over time. [...]
December 16th, 2007 at 9:09 pm
Actually, LEDs are not as efficient as many people think. It is a common myth that they do not even produce any heat! Also, if the LED device is rated for, lets say 60 lm, well that might be the initial output. After several thousand hours of use, this will start to fall out dramatically. However, the generated heat remains, so the LED bulb becomes less efficient. While doing an energy efficiency calculation for LEDs, be sure to account for this degradation over time.