Worried about Vitamin D deficiency or seasonal affective disorder? Looking for a cheaper alternative to the Sperti sun lamp?
In this guide, I’ll walk you through step by step how to build your own vitamin D lamp!
Since this setup also emits UVA, it can also function as a tanning lamp for those of you looking for that.
Why Did I Build This?
I live in Michigan, so for several months of the year, the sun is too low for vitamin D production.
Why not use the Sperti lamp? Well, this DIY lamp is cheaper, more powerful, and safer.
Explaining the UVB to UVI Ratio
You see, reptile owners have done a lot of UVB light testing. And they’ve discovered a simple metric to determine how safe a UVB light source is.
This is the UVB:UVI ratio.
It’s a proxy measurement, but it’s a very useful one.
This ratio tells us roughly how much short-wavelength radiation is present in a light source, without using a $3,000 UV spectrometer (which I don’t have). Please Santa.
Here’s how we figure this out:
At a set distance, say two feet, you measure the UV index and the total UVB in uW/cm2.
As you can see above, the UVB meter detects longer wavelength light than the UVI meter.
If we get a UV index reading of 14 and a total UVB reading of 200 this gives us a ratio of 14.3, while if our total measured UVB was 350 at the same UV index, the ratio would be 25.
A lower ratio is indicative of there being more short-wavelength UVB than long-wavelength.
This is bad because natural sunlight doesn’t go much past 300nm, while lamps like the Sperti go down well into the 250-270nm range.
Here are the average UVB to UVI ratios for the Sperti lamp vs the DIY light I built:
- Sperti: 10.3
- DIY: 25.7
As you can see, the Sperti lamp is producing far more short-wavelength UVB light than our DIY lamp.
So in other words, at a UVI of 14 (where you are recommended to use the Sperti), both lamps have a drastically different amount of UVB.
- Sperti UVB at UVI of 14: 130 uW/cm2
- DIY UVB at UVI of 14: 360 uW/cm2
So you’re able to get exposed to almost 3x more UVB radiation at the same UV index. This is because the Sperti lamp is pushing out more short wavelength UVB, which is sending that UVI up.
It’s unclear if the DIY light will be more effective, but it’s likely that it will be, on top of that, because it has significantly less short wavelength UVB radiation, it will be a lot safer to use long-term.
Hopefully that all made sense.
Let’s build this thing!
The Parts You’ll Need to Build it
First, let’s go over the parts we’ll want to pick up to build our lamp.
Fluorescent UVB Lights
The most important part of this build is of course the lights. For these, I went with the 46″ Dragon D3 made by Arcadia.
I’ve selected this light because it has the highest output UVB I could find and Arcadia makes some really high-quality stuff.
They’re also quite large at 4 feet so we’ll be able to cover far more surface area than the Sperti lamp.
Arcadia 46″ 14% UVB Bulbs
You’ll need four of these total to fill up the light fixture below.
ReptiSun 46″ 10% UVB Bulbs
Here’s an alternative that can be purchased on Amazon if that’s more your style.
Note: I didn’t test these in my setup, but they should work just fine, ZooMed is a reputable brand.
Grow Light Fixture
The fixture we’ll be using is a 4-foot grow light fixture. This is explicitly built for 54w fluorescent T5-HO bulbs, the same ones we’ll be putting in it.
4ft T5 Grow Light Fixture
You don’t have to fill this whole thing if you don’t want to, you could just use two bulbs instead of all four.
It does come with 4 bulbs of its own that we won’t need, so you can recycle those if you want. I’ve been unable to find a fixture that doesn’t come included with lights.
The Protective Screen
The one possible downside to this setup is that it doesn’t come with a protective grate, which is nice to have because fluorescent UVB bulbs utilize mercury. You don’t want to break these bulbs.
If you live alone and aren’t worried about anyone breaking it, you can always skip this part.
The best option I’ve been able to come up with is attaching a metal wire mesh to the front.
1/2 Inch Galvanized Welded Wire Mesh
This mesh is quite stiff and will work well to protect the lights.
Adhesive Zip Tie Mounts
You’ll need something like this to attach the mesh to the light fixture.
Building the Vitamin D Lamp
Okay, now let’s put it all together!
Preparing the Light Fixture
Here’s what you’ll need to do with the fixture.
- Remove the blue protective film from the reflective trays, this is pretty easy.
- Play around with fitting the trays into each other, they come a bit loose but once you play around with them for a bit you’ll figure out how they fit together.
- Clean up any smudges.
Installing the Bulbs
Now carefully pull the bulbs out and install them one by one, these are bi-pin lights, so the connectors on either side install vertically into the fixture.
You may have to push the light fixture connecter out on one end to get the light pins to fit into the slot.
Once it’s sitting in the slot on both ends and is pushed down all the way, you can spin it to the right to lock the light into place.
Now repeat for all four lights!
Mounting it on the Wall
To mount the light on your wall of choice, you’ll want to start by installing a hook or screw of some kind into a stud at around 70″ off the floor.
Next, you’ll hang the light using one of the hooks it came with.
I also went ahead and attached the bottom to the wall using a couple of 3M sticky pads.
Here’s what the finished product will look like:
Installing the Protective Grate
Now for the protective grate, should you want it…
You’ll need tin snips for this part!
Cut off a 49″ long section of the mesh, and begin to make it flat so it’s easier to work with.
Next, place the mesh against the panel and start bending the top portion over, it’s pretty stiff and tough mesh so this isn’t the most effortless process.
Once you have the top done, you can move on to the sides.
The trick here is to bend the sides just a bit, near the top, so that you know where it will need to be bent all the way down.
Once you have a reference point, take the mesh off and bring it over to a flat surface with an edge (like a table or counter) and bend the mesh all the way down on both sides using that edge, it’s much easier this way than trying to do it on the lamp.
Make your bends just a bit more than 90 degrees, this way once it’s attached to the light, the metal won’t want to pull away from the zip-tie mounts.
Once it’s all bent to shape, you can cut out the corner sections that aren’t needed.
And that’s about it! It’s a little bit of a pain, but once it’s done it’s done.
Just stick your zip tie mounts onto the light and start zipping the mesh into place!
Testing the DIY Light
As soon as I began, I realized it was going to be a little challenging, because, unlike the Sperti lamp, this one ramps up to its max within the first 2-3 minutes (if it’s warm).
As you can see, it then slowly comes down to baseline over the next 15 minutes or so.
It’s a bit harder to compare the two because of this.
But I tried anyways.
UV Index Measurements
As you can see from the graph below, this DIY lamp is quite a bit more powerful than the Sperti lamp:
This means that while you get a UVI of 14.3 at 15″ from the Sperti, the same UVI is reached at 24″ for this light.
If you’d like to take a deeper dive into the measurements for this light as well as the Sperti, the google sheets document can be found here.
You can read our review of the Sperti vitamin D lamp here if you’re interested.
Since the UVI pretty much only takes into account UVB and lower, what about UVA?
Well, the DIY light puts out way more UVA than the Sperti light does.
Is this a good thing or a bad thing though?
Well, natural sunlight does produce quite a bit more UVA than UVB, so this seems to mimic sunlight in that regard better than the Sperti.
Of course, this can also double as a tanning lamp as well if you spend more time in front of it.
You may not want this much UVA, perhaps you’re only interested in the UVB aspect, if that’s the case you’ll want to skip this. I’ll see if I can create an affordable narrowband UVB light in the future.
Does UVA Affect Vitamin D Production?
In this study, in which 75 participants total finished. The researchers compared vitamin D production in 4 groups.
UVB only, UVA only, UVB+UVA, and a control.
It was observed that almost no differences were seen in the full spectrum UVA+UVB group when compared to the UVB-only group.
In fact, the full spectrum group actually had a higher mean change in serum D3 than UVB only.
They do note that under longer duration times (≥9 min) UVA may decrease pre-vitamin D3 production. Which is fine, UVA does act as a D3 modulator in nature.
So I don’t think there’s anything to worry about here. In fact, it’s likely a good thing as UVA is useful for nitric oxide production, blood flow, and increasing endorphins.
How to Use Your Vitamin D Lamp
Okay, so it’s built, mounted, and you’re ready to stand naked in front of it.
But how far away? And for how long?
The Warm-up Period
If you use this sporadically, the lights do take a few minutes to warm up.
So if you don’t use it often just give it 5 minutes to warm up first. Once the lights are all shining uniformly it’s good to go, you’ll see what I mean.
However, if you use it every day or every other day, they warm up very quickly.
How Far Away Should You Stand
I recommend placing a piece of tape on the floor about 26″ away from the wall.
This is about where you should stand.
Grab a pair of UV glasses before using this!
The metal mesh grate decreases the UV output by about 10-15%.
If you have the protective grate on, stand on the tape.
If you aren’t using the grate, stand behind the tape.
This will give you a UV index of about 14, just like the Sperti does.
How Long Should You Use the Light
How you react to ultraviolet radiation depends on your personal situation.
Depending on your skin type, diet, genetics, and all the rest, the time to erythema will vary.
Erythema is, for those that don’t know, just reddening of the skin. If your skin is getting very red, you’re standing too close for too long.
Simple as that.
Didn’t get red at all? Feel free to increase the time or stand a little closer. Just only change one variable at a time so you know what is and isn’t working for you.
The Best Time for UV Exposure
The best time to use this would be in the middle of the day, preferably after some infrared exposure. As infrared is protective against UV damage.
For most, the best routine would be to use some kind of infrared light therapy in the morning, followed by a UV light session when they get home from work.
You don’t really want to expose your skin to UV first thing in the morning because it’s just very unnatural. I would think this might have a negative effect on your skin and potentially cause problems with circadian timing and hormone rhythmicity.
Alright, that’s it!
I’ve personally used the Sperti and I can confidently say that my DIY sun lamp feels much better.
It feels warm and powerful like the sunlight I’m so fond of standing underneath when I can.
Hopefully, this has inspired you to build your own!