Replacing my light fixture's GX32D tube with a regular light bulb

I have a 1980's vintage light fixture on the outside of my house.  It uses a two-pin GX32D-2 fluorescent bulb, which is unlike the modern CFL bulbs you see today.  These GX32D-2 bulbs are super-challenging to find, and expensive too.

Even worse than that, the GX32D-2 is a 22 watt bulb - that is a lot of electricity for a modern outdoor house light fixture.  And all that power is used for from dusk to dawn - about 12 hours a day.

My goal is to replace this decidedly old-school GX32D-2 bulb system with a traditional light bulb socket and a commonly available LED bulb.  Here's the fully story.

What is inside a GX32D-2 light fixture

My GX32D-2 light fixture has three major electrical parts: a ballast transformer, the 2-pin bulb socket, and the bulb itself.  If the lamp stops working, it can be due to a bad bulb or a bad ballast.   Usually I try a new bulb first, and if that doesn't work, I replace the ballast.

Nothing is inexpensive when it comes to maintaining these lights. Replacement bulbs, ordered online or from a specialty shop, can cost $15. A replacement ballast can be $12.  Bulb replacement is easy, but replacing a burnt-out ballast means removing the fixture and rewiring. Yuk.  I want to stop all that.

Original fixture setup, with ballast (top) and GX32D-2 socket (bottom)

My Retrofit Goals

My goal is to make a simple, clean and reliable conversion from the existing electrical components, with a minimum of spending.
  • Lower operational power expense by at least 80%
  • Ease maintenance by using a traditional bulb socket
  • Lower bulb replacement costs

Light Needs Analysis: Lumens versus Lux

I want to make sure that my new light set-up will provide as much light as the existing set-up.  The GX32D-2 bulb is 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. But given the GX32D's vertical orientation in my fixture, most of the light is directed sideways, bounces around the fixture and gets converted into heat.  A lamp that directs more light downward will be greatly more efficient, as it will be brighter where it counts. 

I have a this handy 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 I considered to fix the problem

So 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 light fixture and removing the old ballast and socket, but this simple $5 lamp holder socket is the only new part 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 robust.  New fixtures are generally poorly made, or if 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 socket adapter.  There are socket adapters that can convert a 2-pin 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 socket retrofit process

Here is the process I used to replace GX32D socket with a traditional socket.
  1. Removed the fixture from the house.
  2. Removed the baseplate that holds the ballast and socket
  3. Removed the socket and ballast from the baseplate
    • Repainted the baseplate a gloss white
    • Repainted the fixture a satin black
  4. Bought this Leviton lamp holder socket and screwed it into place.
  5. Wired up the new socket with a short (2 foot) length of lamp cord.
  6. Fed the cord through the baseplate and through the lamp.
  7. Reassembled and re-installed.
And there we have it! Now my light fixture uses a standard bulb and is at least as good as new!

The removed bulb, socket, and ballast

Same fixture, but now with a Leviton E26 socket retrofit.

Bulb Selection

Now that I had a fixture with a standard bulb socket, it was time to find the best bulb.

I started with the lowest wattage LED bulb I had laying around - a 3 watt LED bulb that I bought on Amazon.  I measured the light under my new fixture with my light meter, and it was at 169 lux... brighter than the original 22 watt bulb!  Although the LED is, over all, rated at 20% of the lumens of the original GX32D bulb, the new socket orients the new bulb in a very efficient way (downward) as opposed to the GX32D socket which oriented the bulb in the least inefficient way.  So my new 3 watt LED retrofit with a nearly optimal lamp orientation provides more light on the ground than the original 22 watt bulb that was in there!

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 bulb plus its ballast uses 23 watts, while the new LED bulb only uses 2.5 watts - that's a huge 20.5 watts in power savings. Doing the math, this retrofit will start paying dividends in less than three months.


Replacing the GX32D-2 socket in my outdoor lamp with a traditional bulb socket and a 3 watt LED had many advantages and no known disadvantages.
  • saves about $40 a year in electricity costs
  • provides more usable light under the fixture
  • easier and cheaper to maintain, as the new set-up uses commonly available bulbs
  • parts cost was about $8 (for the socket and wire) and took about 15 minutes
The one thing I didn't do was install a photoelectric sensor.  If I ever have a reason to open up this fixture again, I might do that.  Or, imagining the colorful possibilities at the holidays, maybe I'll install a so-called smart bulb.

Update - Two months later

My updated fixture has been running for over a few months and is working perfectly.  It's winter as I write this, and now I see another huge advantage of the LED over the GX32D - light output in cold weather.  The old GX32D-2 bulb would get noticeably dim in freezing temperatures, but the LED is as bright and effective as ever.


When is the best time to do laundry?

I think about energy efficiency a lot, so my question of the moment is... when is the best time to do laundry?  For me, my laundry consists of machine wash and machine dry.

Washer Efficiency
With the wash, the question is when is the best time to use a pretty much fixed amount of water and energy.  I think that's when electricity production is at its most efficient, which is at night and on weekends.  That's because the energy companies use their most efficient electricity generators 24 hours a day, but add less efficient generators as load increases.

Dryer Efficiency
With the dryer, the question is when is it easiest for the dryer to remove moisture.  I think that's during low-humidity times.  Dryers draw in air to work their magic, so the more dry the air is, the more quickly the laundry will dry.

Also, note again that dryers suck in air, and exhaust warm moist air outside.  During extremely cold or hot weather, a heating system or air conditioning system will need to heat or cool this new outside air.  It's good to minimize this expense too.  Therefore, it is best to avoid doing laundry during very hot or very cold weather.

So I try to do laundry on dry nights and weekends.  If it is particularly hot, cold, or damp outside, I'll put off laundry for another day.

Buying the right LED bulbs

With so many LED bulbs on the market, it's hard to choose a good one.  And sadly, no retail web sites that focus on selling bulbs help.

Faceted bulb selection

The sellers of light bulbs should offer a faceted selection tool, allowing the customer to locate the best bulbs they can find.  With over 1000 bulbs on the market, not offering such a selection tool makes it nearly impossible for a customer to find the right bulb.

Here are the facets that all adequate retailer should offer:
  1. Socket Style (traditional E26 Edison, etc)
  2. Bulb Shape (Traditional, Globe, Spot, Candle, etc)
  3. Average Life Minimum  (25k hours, 50k hours, ...)
  4. Light color (warm white, daylight, blue, etc)
  5. Special Features (wet, smart, etc)
  6.  User-specified Lumen Range (350..600, 150..1000, 150..350, etc)
Just a note about numbers.  It is STUPID to offer discrete facets for things like bulb life or lumens.  There are thousands of different possibilities. RANGES are the only non-stupid way to allow such a selection.

From there, once a customer selects one or more facets, a list of products could be produced, sortable by either energy consumption or price tag.

With that, I can say "show me all the bulbs, sorted by energy consumption, that use an e26 base and that outputs at least 225 Lumens".  Pretty simple, eh?  Shockingly, NO RETAILER OFFERS SUCH A SIMPLE TOOL.

My Facets for Selecting Bulbs
Here is what I generally care about:
  1. QUALITY.  Buy only highly rated bulbs.  No-name bulbs without a track record are not worth the investment.  They might be great... or they might look awful and last 6 months.  Only buy bulbs that have a real warranty and a good reputation to lose. If in doubt, stick with the hugely popular name brands.
  2. COLOR.  Stick with the same light color, and buy in lots.  LEDs have many different color options, such as "warm white" and "cool blue" and many others.  It looks a bit silly to have many different colored lamps in proximity to one another, and so if you're outfitting a room, stick with the same color bulb and preferably use bulbs from the same package.  My personal choice is to use warm white bulbs with a color between 2600K and 3000K.
  3. LIFESPAN.  Buy bulbs with a long life.  Buy bulbs that are have have an estimated life of at least 22 years or 25,000 hours. Anything less suggests that the bulbs are poorly designed.  Of course, being an average, some bulbs will not last as long as promised, and some bulbs will last considerably longer.  I write the date on all of the bulbs I install so that I can determine if a bulb fails prematurely.
  4. CONSUMPTION.  Go with the lowest actual wattage that is adequate for your needs.  I find that 3 watt bulbs offer plenty of light for many uses around my home.  In hallways and bedrooms I go with the 3 watt bulbs that produce about 225 lumens.  In the kitchen, living room and bathroom, I use 5 watt bulbs that output about 500 lumens. Strangely, many LED retailers focus on bulb brightness, and leave wattage as an afterthought.
  5. QUANTITY.  Minimize bulb count.  Some fixtures can use two or three or more bulbs.  Do you need them all?  Generally, more bulbs means less efficiency.  If a fixture can accept two bulbs, can you instead go with one?
And there you have my criteria for buying LED lightbulbs.  Now that I've outfitted my house with bulbs that are supposed to last 50,000 hours, I won't have to buy too many more bulbs in my lifetime.  After all, at 3 hours per day, that's more than 45 years.


Using Recovery Mode on my Lux Thermostat

I've had this Lux programmable thermostat for years, and it's worked perfectly great for me.

But this week I just learned about enabling Recovery mode, and it both works great and should save me more money.

What is recovery mode?

Normally, a programmable thermostat is a device that is used to turn on the heat at a user-specified time in order to meet a user-specified temperature.

In contrast, a recovery mode programmable thermostat is a device that ensures that a user-specified temperature is met at a user-specified time.

The difference seems subtle, but in the real world, recovery mode makes a big positive difference in terms of living comfort and heating efficiency.

When using a thermostat, it can take a variable amount of time for your heat to come up in the morning.  Let's say you want to be up and about a 7 AM with a house temperature of 68 °F.  When should the heating system come on?

Well, that depends on your heating system, how cold it is outside, and how cool your house is.  If it was warm last night, with a low temperature of 67°F, it will take only a few minutes of heat to get to temperature.  But if it is cold, say down to 60°F inside and 20°F outside, it could take an hour for the heating system to suitably warm up the place.

A thermostat's recovery feature automatically figures out when the heat needs to come on in order to reach the programmed temperature at the right time.

I generally want to keep my house at 68 °F during the day (from 7 AM), and I set the thermostat to 60 °F at night.  I don't want the heat to turn on at 7 AM - I want the house to be 68°F warm at 7 AM.  With recovery mode, I just program my thermostat to "68 °F at 7 AM", and from there my thermostat works to make sure that's true.

The thermostat uses the current temperature, the goal temperature, and the recently recorded speed of the heating system to figure out when to turn on the heating system.  Today the thermostat might calculate that the heating system needs to come on around 6:42 AM to reach 68 °F at 7 AM.  When it is much colder next week, the thermostat might determine that the heating system needs to be turned on at 6:35AM.

In all, this means that the thermostat will work as efficiently as it can in order to keep my house at the right temperature for me.  All this in a $50 thermostat.  Pretty nice.


Recovery Mode is working perfectly on my Lux thermostat.  Now that it's really cold out, the thermostat turns on the boiler one hour before my morning settings.  That's the maximum amount of time the Lux will pre-start the boiler.

Out in these parts, with my heating system, my building, and brutally cold weather, an hour isn't enough time.   But it's better than no additional time.

I currently set the night temperature at 64 degrees.  By setting it at 65 or 66 degrees, the house would get to temperature in less time.  It's rare that the boiler comes on over night, and when it does, it is generally colder than 10 °F outside.  At that point, my energy savings plan goes out the window.

The Price of Electricity

I'm sitting at home here looking at my electric bill.  My bill says that electricity costs 21¢ per KWH.  But that's not true. The ...