I’ll admit there’s probably something wrong with me that I care this much about two $15 light bulbs. And the old me a few years ago would cringe at spending $15 on a light bulb. But there you have it.

I’m comparing the GE Link bulb (clear globe) with the Cree Connect (frosted globe). They’re both ZigBee bulbs, rated at about the same brightness, and are both compatible with some of the most popular home automation hubs (Wink, Smart Things, Staples Connect). I’m using both on a rooted Wink Hub. The parameters I’m interested in:

1) Electrical power usage and longevity

2) CRI and color temperature

3) Highest high (how bright?)

4) Lowest low (how dim?)

Here’s my readings for energy consumption measured using a Kill-A-Watt. I’m surprised that the bulbs draw 0.4 Watts when they’re in the off state (powered on, but no light output). Most of that is wasted power used to convert AC to the tiny amount of DC current needed for the zigbee microcontroller.

[Watts] High (Brightest) Low (Dim) Idle (Off) Cree 11.3 1.3 0.4 GE Link 11.3 1.0 0.4

Let’s assume we’re running a bulb for 5 hours a day at $0.08 per kWH electricity cost. A 60W incandescent would cost $8.70 per year, while these LED’s would cost $1.7 per year. The LED bulbs also have a much longer life expectancy, 25000 hours compared to 2000 hours for incandescent. Even if we halve the listed life expectancy for the LED’s to 12000 hours, that’s over six years bulb life. Over that six years, you’ll spend $42 less in electricity when using LEDs.

When CFL bulbs first came out, they had horrible life expectancy. Mostly I think because of the power electronics (probably capacitors) getting hot and failing over time. But they got much better, and I’ve had CFL bulbs in my living room (highest usage case) that’s lasted six years. It’s not too much of a stretch to believe that the component longevity would extend to these LED bulbs.

CRI & Color Temperature

The color temperature looks the same to me, and they’re both rated at 2700k. You can decide for yourself in the photos later. They’re all taken at 4200k white balance on a Canon DSLR (just happen to be at that setting for all the pictures). I should’ve set the color balance on the camera to 2700. Once I started, I wanted to keep all the settings the same, so I just left it as is. As a result, the pictures look really red, but that’s my fault. They’re both nice looking bulbs, and the 2700k rating is about right. I don’t have anything fancy to measure color rendering. They look sameish for CRI.

Highest high

You can decide for yourself. This is with the bulbs turned on manually, so they should be at the highest setting.

Lowest low

I took all these photos at these settings.

F/4.5

1/30 sec

ISO-400

30mm lens

Color temp: 4200k

To my eyes, both bulbs have about the same low level. The frosted lens on the Cree spreads the light a little differently than the GE, but they look the same if you’re sitting in the room looking around. I wish the bulbs could dim even lower. They’re much too bright as a night light. The low setting is bright enough to let you spot things on the floor before tripping over them.

Testing Details

One note about the low settings. I’m using aprontest on the GE Links to set the low to level=1. On the Cree, I was using the Wink app, which seem to set the low to level=3. Hoping that’s negligible since the value ranges from 1-255.