Even worse than that, the GX32D-2 is a 22 watt bulb - that's a lot an electricity for a standard outdoor house light fixture. It's simply a light to help guide the way, so it doesn't need to be bright enough to read by. And it's on for 12+ hours a day.
My goal is to replace this 22 watt bulb system with a traditional light socket and a commonly available LED bulb.
What's Inside the GX32D fixtureThe light fixture has three major electrical parts: the ballast transformer, the bulb socket, and the bulb itself. If the bulb stops working, it is usually either due to the bulb or the ballast. Replacement bulbs, ordered online or from a specialty shop, can cost $15. A replacement ballast can be $20. Bulb replacement is easy, but replacing a burnt-out ballast means removing the fixture and rewiring. Yuk. I want to stop all that.
My Retrofit GoalsMy goal is to make a simple, clean and reliable conversion from the existing electrical components, with a minimum of spending.
- Lower power expense by at least 80%
- Use a traditional light bulb connectors
- Ease maintenance
- Lower bulb replacement costs
Light Needs AnalysisI want to make sure that my new light set-up will provide as much light as the existing set-up. The GX32D bulb is generally rated at 1200 Lumens, but I don't need to replace it with another 1200 Lumen device to get the same brightness.
Lumens is the measure of all of the light leaving a bulb, but lux is the amount of light falling on a particular spot. One thing about my outdoor light fixture is that the light is supposed to shine light mostly downwards in order to illuminate the ground. A lot of the light ends up inside the fixture and gets converted into heat. A lamp that directs more light downward will be greatly more efficient - and possibly brighter.
I have a light meter, so I can measure the actual light output to test different options.
Therefore, in order to get a baseline of the existing set-up, I measured the light output under the lamp at a distance of 1 yard. The meter reports 160 lux. Any new bulb should shine 160 lux under the lamp.
Some options to fix the problemSo at this point I know what I want, but now the question is how to do it. There are lots of solutions. Here are the three that I looked into:
Replace the socket. This is the solution I chose. It means taking down the lamp and removing the old ballast and socket, but a simple $5 lamp holder socket is the only new parts that is required.
Replace the fixture. Another solution is to completely replace the fixture. But I actually like my old fixture's style quite a lot. It's made out of heavy cast aluminum, and so it is quite tough. New fixtures are generally poorly made, or it they're not poorly made, they're very expensive. It's a shame to go throw this one away when the only thing wrong with it is the bulb it requires.
Install a bulb adapter. There may be adapters that can convert a GX32D socket into a traditional socket. But you still have to remove the ballast from the circuit, and the adapters are hard to find and expensive too. This seems like the worst solution.
The processHere is the process I used to replace GX32D socket with a traditional socket.
- Remove the fixture from the house.
- Removed the baseplate that holds the ballast and socket
- Removed the socket and ballast from the baseplate
- Repainted the baseplate a gloss white
- Repainted the fixture a satin black
Bulb SelectionNow that I had a fixture, it was time to test the light output of various replacement bulbs. Of course not everyone has to do this, but I figured I have the equipment, so why not.
I started with the lowest wattage LED bulb I have laying around - a 3 watt LED that I bought on Amazon. I measured the light under my new fixture at 169 lux... brighter than the original 22 watt bulb! It turns out that the fixture oriented the GX32D bulb in a very inefficient way, and so my new LED retrofit with a nearly optimal lamp orientation provides about the same light on the ground.
Since this was the lowest wattage bulb I had, and since it threw plenty of light, I went with it.
Just for fun, I measured the actual power usage of the old and new bulbs on my kill-o-watt power meter. The GX32D light and ballast uses 23 watts, and the new bulb only uses 2.5 watts - that's a huge 20.5 watts in power savings.
- The basic relamping cost about $8 (for the socket and the wire) and took about 15 minutes
- The repainting cost about $6 (for spray paint)
- The LED retrofit saves me about $40 a year in electricity costs
- The LED retrofit provides the same light