Light bulbs: Compact Flourescent Lights (CFL) versus Halogen

Light Bulb

I came home late last night and flicked the hallway light on.  Instead of being greeted by a warm cozy glow, there was a harsh, dim, blue-white light…  that got brighter and harsher a few minutes later once it kicked in.  What the heck?!

I’d just replaced my hallway lights with new CFL lights and at that moment was sorely disappointed.  Yes, they’re supposed to be highly energy efficient but why do they have to cast such an ugly light?  And take so long to kick in?

But.. since I’m growing an even bigger eco-conscience these days … it told me to give the CFL another chance.  So what is a CFL and why do “green” builders have it on their proud list of things that make their product green?  (It also happens to be on my own list of things that are making my new small house extremely energy-efficient, too).


English: Compact fluorescent light bulb

– The compact fluorescent light bulb (CFL) is different from the halogen bulb in one major way:  it requires almost four times less electricity to produce the same amount of light.  In terms of physics, the energy efficiency of a light bulb is measured in lumens per watt – meaning, how many watts of electricity does it take to produce x lumens of light.   A 75-watt halogen bulb produces 1100 lumens of light.  However, a CFL bulb requires only 22-watts to produce 1100 lumens of light and is therefore more energy efficient.

– The CFL also produces much less heat.  The old fashioned halogen bulb takes electric energy and uses only 10% of that energy to produce light.  So what does it do with the other 90%?  It turns it into heat.  So, I did a little test that goes against everything you learn as a kid:  do not touch a burning light bulb.  Well, I touched the burning CFL in my bedside lamp after it had been burning for an hour and guess what?  Ok, it was still hot, but definitely not scorching.   The CFL converts 70% of electric energy into light, and only 30% to heat which is why it is much cooler.

– the CFL lasts 8 times longer (8000 hours vs 1000 hours).  This translates into far less replacement cost and also eight times less that you’ll be getting up on that ladder to change light bulbs (or eight times less you’ll be nagging hubby to do it 😉 )


Halogen incandescent light bulb

– So what about the color?  This is where the halogen light bulb wins.  While certain CFLs labeled as “soft white” have a warmer glow than the others, it’s still not as warm and fuzzy as the halogen bulb and definitely not as warm and fuzzy as the standard incandescent bulb.

– Another con to CFLs is the start-up delay with certain types (those packaged as flood lights, for example).

– Lastly, they contain enough mercury to require hazardous waste collection.  Do not just throw a used CFL out with the regular trash.  Call your city’s waste management department and ask how they collect residential hazmats. Broken CFLs can leach mercury into landfills.

So what do I think?  I think CFLs win hands down, purely because of their superior energy efficiency.  Plus, I found a CFL that actually does produce a warm glow (it was top rated in by a guy who’s job it was to test all these light bulbs and report on the best ones).  That one is the GE Reveal Spiral CFL.  Try it out!




DeGroot, Paul.  Energy-Saving Light Bulbs. Fine Home Building.  Winter 2013: 86-91.


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