A standard incandescent lightbulb produces roughly 90% heat and 10% light.  Compare this to a LED bulb which emits roughly 90% light and only 10% heat, you can see the potential for huge energy savings! But how do you pick the right LED and avoid that dreaded blue hue color that makes you feel like you should be wearing sunglasses inside?

Bulbs are rated on at least two critical indexes: CRI (Color Rendering Index) and degrees of Kelvin. Balancing these two numbers holds the key to creating warm light suited to you and your home.

CRI is measured 1-100 and rates the ability of light to show an object’s true color.  Sunlight is rated at 100. Look for compact fluorescent bulbs with a CRI rate of 80 or higher.  Look for LED’s with a CRI rate of 85 or higher.

Degrees Kelvin are used to describe how “cold” or white a light is.  Most office lights rate about 4,000 Kelvin. Since most homes aim for a more “warm” lighting, look for bulbs in the 2,700-3,000 K range.  (A standard incandescent bulb rates around 2,800 K.)

My personal favorite bulb is a LED with a CRI of 90 or higher and a Kelvin rating of 2700.  Even today it is still difficult to find a CFL above 80.  Added benefits of LED Bulbs:  No long warm-up phase as with most CFL’s, May be used in motion lights when instant on is critical.  Not conducive to attracting bugs compared to CFL’s or incandescants.  Very long life compared to CFL’s and incandescants.  LED’s generate very little heat that has to be removed by your air conditioning system.

2 replies
  1. mike grober
    mike grober says:

    very useful … i guess the latest generation of cfc’s are better than those manufactured a couple of years ago?

    • jonathan
      jonathan says:

      Yes, when CFL’s first came out, they were mostly what I call school house white. They gave off alot of light, but didn’t show true colors and really almost made you squint. Consumers, rightly so, hated them. Now, we have warm color CFL’s that most people can’t tell aren’t incandescent!
      The next step is LED lights. I just bought some and they are fabulous, but so was the price tag. Roughly $50 per bulb, they last 50,000 hours CRI of 92 and K of 2700. Very expensive now, but operate for just a fraction of what CFL’s cost to run. Good CFL’s were expensive in the beginning also. Just remember, CFL’s take about 60 seconds to reach their true light. So, closets, motion detectors and pantries are not good places for them.

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