DIY vitamin d blog post featured image

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!

  • Does It Work?

I’ve officially finished the DIY build, and it works! See later in this guide for details on my regimen.

vitamin d test results

Since this setup also emits UVA, it should also be able to 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, emits more UVB, and it appears 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.

uv meter measurement ranges compared to sunlight
UV meter measurement ranges relative to natural sunlight

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. However, there are other options out there which I’ll link to below.

I’ve selected this light because it has the highest output UVB I could find at the time and Arcadia makes some pretty 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

arcadia uvb light product photo

You’ll need four of these total to fill up the light fixture below.

ReptiSun 46″ 10% UVB Bulbs

reptisun uvb lamp product photo

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.

AgroMax 75% UVB T5

75% uvb bulb

A reader of ours found this 75/25 UVB/UVA bulb! If you’re more interested in a pure UVB bulb this might be worth trying out!

Grow Light Fixtures

The fixture I used in this project was a 4-foot 4-bulb version explicitly built for 54w fluorescent T5-HO bulbs. However, you can get one-bulb or two-bulb versions as well if you’d like to try something less powerful.

4 Bulb T5 Light Fixture

vivosun 4 bulb fixture product photo

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.

2 Bulb T5 Light Fixture

2 bulb fixture product photo

1 Bulb T5 Light Fixture

one bulb fixture product photo

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.

mesh screen product photo

1/2 Inch Galvanized Welded Wire Mesh

This mesh is quite stiff and will work well to protect the lights.

zip tie mounts product photo

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.

  1. Remove the blue protective film from the reflective trays, this is pretty easy.
  2. 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.
  3. 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.

closeup image showing hook attachment to screw in stud
Just like that! Don’t mind the crack in the wall, it’s not that heavy, that’s just my amazing drywall work.

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:

the diy vitamin d lamp fully installed on the wall

Not bad!

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.

  • Tip

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.

closeup view demonstrating the cut corners of the mesh
Example of how the corners will look once you’ve cut them to shape.

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

  • Testing Information

I hope to purchase a professional UV spectrometer (>$2000) one day to improve this testing, in the meantime, this is the best I’ve got.

I used the UVA, UVB, UVC, and UVI meters from Solarmeter to test this light setup.

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).

the uv index over time at 25 inches from light
UV Index @ 25″ over a 15-minute time span

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 anyway.

UV Index Measurements

As you can see from the graph below, this DIY lamp is quite a bit more powerful than the Sperti lamp:

sperti uvi vs diy uvi bar graph
UV Index of Sperti lamp vs DIY 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.

  • Learn more

You can read our review of the Sperti vitamin D lamp here if you’re interested.

UVA Measurements

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.

bar graph of uva from sperti lamp vs uva from diy lamp
It produces boatloads more UVA than the Sperti lamp

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?

Kind of.

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.

uva and uvb vitamin d study screenshot

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.

UVB LED Options

Several studies have shown that UVB between 293-295nm is the most effective at triggering the production of Vitamin D. However natural sunlight has almost no light in this frequency range so I have concerns with trying to emulate this…

It’s not easy to find UVB LED products on the market just yet, but here are some of the options I’ve found so far:

Zoo Med ReptiSun UVB LED

reptisun uvb led

This might be the most legit UVB reptile light out there right now since they actually provide a spectral graph report:

reptisun uvb led spectrum graph

Looks like around 306nm LEDs for the UVB portion which may or may not work well, I’m not sure.

I’d try using these for a minute at 1-2 feet away to start? But I haven’t tried them myself yet.

Here’s an in-depth report I found.

Aiicioo Reptile LED UVB Light

Aiicioo Reptile LED UVB Light

I’m not sure what wavelength these UVB LEDs are but they’re a bit larger than the ReptiSun so the coverage might be a bit better.

The wattage still maxes out at 9w so overall they should be similar in output.

Chroma D-Light

chroma vitamin d light

By far the most expensive Vitamin D light on the market, but probably the most legit, safe, and effective way to get vitamin D there is.

The combination of red and Near-IR combined with narrowband 297nm UVB LEDs make this a powerhouse.

Use coupon code OYB5 for 5% off!

How to Use Your Vitamin D Lamp

Okay, so it’s built, and mounted, and you’re ready to stand naked in front of it.

But how far away? And for how long?

The Warm-up Period

You’ll see the lamps aren’t evenly lit up when first turning it on, they take a few minutes to fully warm up.

So wait until they are uniformly lit to use the lamp.

How Far Away Should You Stand

I currently use my lamp at a distance of around 14-16 inches.

I’d start at two feet for safety.

  • Tip

Grab a pair of UV glasses before using this!

How Long Should You Use the Light

How you react to ultraviolet radiation depends on your personal situation.

Getting my vitamin D from 23 ng/dL to 39.2 took about a month, and I spent about 10 minutes per day in front of my lamp about 5-6 days a week on average.

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 very unnatural. I would think this might harm 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!

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  1. Hey Derek, thinking about building my own – would the 22″ bulbs and matching enclosure be pretty much the same process and specs, if I wanted something smaller like the sperti for primarily torso/back exposure? Do you think it would be a bit risky to use this set up without testing with all the UVA/B/C meters or pretty safe since it’s from a reputable brand (Arcadia)? Thanks for the write up, it’s very illuminating.

  2. Hey Derek – thanks so much for this, brilliant as ever. I agree its much cheaper than my Sperti d lamp and more powerful obviously and a larger surface area for tanning means less time and more comfort. The only thing bothering me is the UVB/UVA mix. I am not sure I want a higher UVA content, it’s unclear to me whether this is an advantage or not. It more closely resembles natural sunlight for sure, but its not full spectrum either so uncertain if this is a benefit. UVA rays do not contribute to vitamin D production, its clear that stops at around 310nm, but they do contribute to skin damage and possibly malignancy as the rays travel much deeper into the skin. I am not interested in getting a tan, so really want to maximise the UVB benefits of D production in the skin. After 30plus years of observations, I am certain that D3 from a bottle is nothing like D3 made in the skin.
    I am only 1 week into the Sperti but will update my results here after a month or so. I won’t be relying too much on the test levels as supplementing with 10K of D3 for many months raised my levels to high but did precisely nothing for my health and well-being I will be going on symptoms being relieved and my well being. That is obviously much more important to me than numbers on a sheet.
    My observations so far with the Sperti are that 3-5 mins every other day does seem maybe to be too little – I am maintaining a clear limit at 15inches. I will do 5mins a day back and front for a while and then hopefully switch to a maintenance programme of hopefully 5mins every other day. I know I am still very deficient so need a kind of loading dose to catch up.
    BTW the link to the fitting fixture says no longer available. However you can buy the desert lamps with the full kit, you get a fitting with each tube obviously but it still works out way way cheaper than a Sperti and you could choose to use 3 tubes only say and still get the much improved coverage. Hope this helps someone.

    1. Good to see you read it Tom!

      I hear you on the UV ratio, it was something I was unsure of at first, but I’m quite happy with it. While it’s true that UVA doesn’t contribute much to vitamin D, it does contribute to nitric oxide production, as well as endorphin release.

      I can say with absolute certainty that this lamp feels more like genuine sunlight and I have a feeling that’s from the endorphins.

      In this study, they took 14 UV bed users, and had them use tanning beds with UV light and with UV light filtered out. The heat was kept similar, just the UV was filtered out, so blinding was in effect.

      The beds UV spectrum was 4% UVB and 96% UVA, so quite a bit more UVA than our DIY light above.

      Even though the beds they were using were blinded, they still chose to continue using the bed with UV. Showing that UVA was producing a noticeable positive effect in these users.

      Very interesting if you ask me!

      So yes if you’re only interested in vitamin D production, narrowband UVB will do that better than a fuller spectrum light source like the one used here.

      However, I’m of the mindset that there are copious benefits to full spectrum UV beyond just vitamin D.

      1. “However, I’m of the mindset that there are copious benefits to full spectrum UV beyond just vitamin D.”
        I am without doubt you are right – that boost you get from a summer hol by the sea is unbeatable and vitamin d is just a part of that. I suspect sea bathing is infusing your body with minerals that go straight to the bloodstream transdermally I also suspect that UV light oxygenates your blood and ozone is involved too. Probably as you say a whole bunch of things going on. I will give the Sperti light 60 days and then I may make the Desert T5 version myself.

          1. Negative ions, ozone, transdermal minerals – lots to talk about – cant wait – this is true health.

          2. Could you shine a quick light on your experience with negative ions, do you have experience with generating them at home with an air filter or something? What are the effects?

        1. I notice too you cite this book

          The Ultimate Guide To Red Light Therapy: How to Use Red and Near-Infrared Light Therapy for Anti-Aging, Fat Loss, Muscle Gain, Performance Enhancement, and Brain Optimization

          A while ago I built a red light therapy device with a mixture of 1w leds in the 660-850nm range. I am wondering if you have experimented with this wavelength of light and if so what benefits you noted. The commercial offerings seem very very expensive for what is essentially a box with a bunch of LEDs and a fan. They of course claim almost miraculous powers however.
          Of course this wavelength of light is a big part of sunlight and may help to explain some of the benefits of real sunshine and maybe how this part of the spectrum prepares the body for UV light later in the day. Its all very fascinating for sure and a much more complex picture than most would understand I guess.

          1. I couldn’t agree more. I haven’t played around with wavelength specific IR therapy myself yet, as you said it’s very cost prohibitive.

            I have used incandescent infrared, much of this peaks in the IRA range so it contains a lot of beneficial infrared radiation for relatively little cost.

            However, the one downside to blackbody infrared is that it also puts off quite a bit of IRB and IRC. Since natural sunlight is filtered through the atmosphere, water vapor actually absorbed a lot of this.

            So sunlight is quite heavy in IRA and quite low in IRB and IRC.

            You can mimic this water filtered infrared phenomenon by simply shining incandescent light through water! This is called wIRA and is actually used medically, however there are no real viable commercial devices.

            I’m still trying to figure out an easy way to create one, as I think it would be the ideal infrared therapy device.

        1. Yeah it is, that’s why I ended up making my own 😅

          So for that bulb it would depend on the fixture or reflector used. It would work though, can’t say how well or anything, but yeah you’d make vitamin D No doubt about that.

          Really wish companies would provide better information. The product box likely shows UVI at various distances, but hard to say without knowing that.

  3. Hey Derek!

    Thank you and much love for all the incredible info you’re giving away for free.

    Could you speak a little bit to how Vitamin D Sun Lamps fit in with the rest of your lighting setup?

    Do Vitamin D sun lamps replace Light Therapy lamps for you? Do you use them synergistically with full spectrum light bulbs?

    It gets to be a lot– there seems to be benefits from wake-up lights, Vitamin D lights, Light Therapy Lights, Full Spectrum Lights, UV Lights, IR Lights, evening lights, etc…


    1. Hi again 😀 I know there’s a lot to learn and incorporate!

      So for us, the vitamin D lamps come out around maybe late December to February to help make up for the lack of UV light. We try to use it once every other day or every few days in the afternoon after exposure to some infrared as would happen in nature.

      This lamp doesn’t replace a bright light therapy lamp though! Although it can be quite bright, we don’t use this in the morning, and thus it doesn’t full-fill the roll of being a visual light therapy lamp.

  4. Hi – this feels like a stupid question, as I’m sure that I’m just missing something, but I saw 75% UV-B (25% UV-A) T5 bulbs on Amazon, so I’m wondering if there’s a reason not to use them??

    They have a spectral map showing that almost all of the light is >300nm and starts around 280nm, while the Sperti is 250-400nm.

    Is there something I’m missing?

    1. Definitely not a dumb question! That’s a great find! Not sure how I never ran across those, I’m going to add them to the post for others to see, so thank you 😀

      I would just make sure to be more careful with these as they’ll definitely be more powerful than the ones I originally used obviously due to the higher UVB content.

      But I don’t see why you wouldn’t be able to use these.

      1. Looking for some advice form someone who knows nothing about this except that I need vitamin d to get through this winter. Any thoughts on using the 2 lamp fixture , with one agro max bulb and one of the dragon bulbs? Not sure if you can even do that.. trying to buy some materials and dont want to waste my money! Im short on space so i think 2 lamp would be better in my home.

        Thank you!

  5. Really awesome and inventive idea. You mentioned in your Sperti review that it had low magnetic and electric fields past 6 inches. Did you perform a similar test with this DIY setup? Would be very interested to know how it fares. Thanks for the great content.

  6. Hi Derek,

    How can we calculate approximately how much Vitamin D we are making per minute exposed to the lamp? I’m using Arcadia 46″ 14% UVB Bulbs at the distance you recommended for 7 minutes per side, 14 minutes total. Thanks!

    1. Hi Amber!

      I’m not quite sure to be honest! It would depend on skin tone and various other factors. Although you could try one of these D3 meters. Perhaps I’ll get one some time to check my lamp.

      The DIY lamp I built puts out around 4-5x the UVB at similar distances as measured by the UVB meter I used at the time.

      Sperti saw a 1000 IU per day average when using their lamp for 5 minutes, three times per week over a 4 week period. So I’d expect your regime to be far higher than 1000 IU per day!

      The only way to know for sure would be to keep track of your usage and do before and after blood testing to average out the increase.

  7. I picked up some of those Agromax Pure UV bulbs. For anyone curious, their UVB to UVI ratio comes out to around 10.3. I suspect they use a similar internal configuration to the Sperti bulbs. Other than that, they’re super strong and focused specifically on UVB with very little else.

    Derek, how much of a deal breaker do you think that’d be in terms of safety and effectiveness? I really like the bulbs otherwise, but that one factor does make me question them a bit. I’ve had a tough time finding additional info on the UVB to UVI ratio. Would you be able to provide some more resources on that?

    1. Thanks for sharing that Joe! So the UVB-UVI ratio thing is just a proxy measurement since I lack the necessary equipment to test the actual spectral power distribution.

      This ratio is often used in the DIY reptile lighting sector for determining the safety of bulbs for folks similarly lacking the funds to measure accuracy with a higher end spectrometer.

      Since it’s only a proxy, we can’t say for sure if there’s any merit to safety concerns.

      You may be correct that these emit a similar range to that of the Sperti bulbs. I hope to one day buy a full range UV-VIS-IR spectrometer so I can officially test and document these things fully.

      But until then we’re mostly guessing unfortunately.

      1. Hey, enjoying your content and how it may positively benefit health and wellbeing.
        I would and maybe others support your projects. If you could set up a payment or funding page so we are able to contribute for you to purchase equipment which we all will benefit from?

        1. Hi Saf! Thanks so much for the support 😀

          I currently have a paypal donation link on my database pages that would work!

          Maybe I should see about making something a bit more obvious? It would certainly help as there’s definitely equipment I would like to buy that I cannot currently afford! haha

          Thanks again and I’ll keep this in mind!

  8. you sure the sperti goggles work to protect the eyes with this setup? tried mine today for the first time and my eyes have been hurting all day. I even had them closed while looking at the light. Are they possibly not suited for this setup because of wavelength variations or because of the uva?

    1. No the Sperti goggles should be blocking all UV, checked them myself, and used them on my lamp with no issues. If they were on all the way it’s either placebo or coincidence. However you can always buy another pair or get some black out glasses if you’re concerned.

  9. What’s the average time people are spending in front of their lamp? I’m a Fitzpatrick type II and have been doing 9 minutes per side (x2) = 18 minutes total standing at 26” away. Do others spend more or less time in front of their lamp? I haven’t reached erythema yet at 9 minutes per side and I’m not wanted to get burned. Thanks!

    1. I haven’t heard of anyone hitting erythema yet! But I also haven’t heard too many protocols, so I’m not sure how long others have pushed it.

      That’s pretty good for a type 2 though! I’m a 3/4 and so I’ve also never had any burning from this. Either way I would think a 9 minute session is more than enough for an effective dose so I’m not sure if pushing it further is necessary, but everyone is different so the only way to truly know is to experiment!

  10. Thanks Derek for this valuable information. I was planning to buy a spectri until I saw this article. I’ve got all the parts on order but the 4-bulb fixture still hasnt shipped. Are there fixtures at Home Depot or Lowe’s? Or Prime 2-day shipping? What specifics should I be looking for? Thanks again!!

  11. Hi, Derek

    I’m excited I found this DIY on the UV Lamps. I have a question, I’ll like to build a system like Yours including two bulbs.
    What I’m looking for is, Tan my skin but also Vitamin D production, so I’ll like Your opinion and advice on which of the 3 bulbs You have mentioned would be best for what I’m looking for. If mix and match two of the three bulbs You have mentioned and which one?

    Thank You in advance.

    1. Hey Milo! To be perfectly honest, I’m not sure! This is all very experimental. I’d have to imagine the 14% Arcadia might be the go to since it’s right in the middle of the others.

      I’m hoping ot one day get my hands on a professional UV meter and really test these to narrow down the best bulbs for these purposes but for now we only have the preliminary data to go off of as well as the claims of the manufacturers.

  12. Hi Derek. I made the light with the AgroMax bulbs. After 20 minutes front and back with a BioMax 600 Ir/Nir I stood with my back to the UVB/UVA light at 4′ for 4 minutes. I have never had such a “sunburn” as I get from that one exposure! It took me about a week to recover to a tad darker than normal before I did the same process but at 4′ for 30s. That seemed fine. I can’t afford the Solarmeters right now. Do you know anyone whose built the same light that’s been able to make the UV Index calculation?

    1. Oh wow! Thanks for reporting back! This is the first I’m hearing of it! Sounds like a very effective bulb haha

      Good idea using the infrared first, that should help. Once I get my hands on a UV spectrometer I’ll be testing all of these bulbs a bit more in depth so we can really see what the best setup is…

      For now we’re all experimenting 😅

      Thanks for this though!

  13. Great stuff Derek. I appreciate all you hard work and easy to follow instructions. How do you think the output would be different if I were to just have 2 46” Arcadia Bulbs? Could we assume about 50%?

    Ty again

  14. Hey Derek, thanks for all this amazing work you do!

    What’s your opinion on using IR and the UV lamp at the same time?

    I’m considering pairing this up with 4 or 6 incascent infared heat lamps, and as far as I can reason this is only like the exposure you would get from natural sunlight.

    1. You’re welcome Liam! I think that’s a great idea! Infrared with the UV is definitely more consistent with sunlight and would be healthier. I haven’t done this on my setup yet but I would recommend it if you can find a way.

  15. this is great!!
    I want to build one of these.
    Can I pay you to build me one?
    I live near you in Brighton?
    I have friends that would want one also once I show them!

  16. Hi Derek! Thank you for this article.
    Im curious, how does the Arcadia 14% UVB bulb compare to the natural sun? I believe the sun is 95% UVA/5% UVB, correct? Is the Arcadia bulb 14% UVB and 86% UVA or am I misunderstanding? Thanks

    1. That’s correct! It’s referring to the ratio. Arcadia does sell lower UVB output bulbs, so you can definitely get closer to the Suns natural ratio. It’ll just take longer for vitamin D levels to rise.

  17. Hey Derek,

    Thanks so much for taking the time to create these instructions in such an organized and accessible manner. All of this information is incredibly invaluable. I’ve been a teacher for 25 years and can spot a natural from a mile away. You have a great talent in regards to you ability to instruct. I think you’d make a fantastic teacher.

    Back to the subject at hand, i was hoping to get some clarification/advice…if possible. I am extremely deficient in vitamin D. I also love the sun and have always wanted a home tanning lamp. Do you think it would be possible to also run regular tanning bulbs in the 4-bulb fixture (are there fixtures with even more bulbs?)? I get lost in the technical jargon and was hoping you could help me find some decent tanning bed bulbs that I could switch in so I can get some good color. Any guidance or specific suggestions would be much appreciated. Again, I really appreciate you for taking the time to educate us. I recognize the time commitment something like this takes and am truly thankful for all your efforts. I hope to hear back from you soon.

    stay well,


    1. Hi Anthony,

      Thanks for saying so 🙂 I quite enjoy learning and then distilling that information into the most practical information I can think of. It’s always a pleasure to see my hard work genuinely appreciated so thank you!

      I will say that the 14% UVB Arcadia bulbs definitely tanned me during use, so I think they can easily function as a tanning bulb since they have a ton of UVA in them. However you can certainly buy lower UVB bulbs with higher ratios of UVA in them as well. You can buy standard tanning bulbs online but they won’t fit in the same fixture as the higher UVB reptile bulbs I use for vitamin D unfortunately.

      You can also get much larger than 4-bulb fixtures, they also come in 6-8-10 variations. A good tanning setup might be two 4-bulb fixtures in a mild V shape or four 2-bulb fixtures in a wide U shape? Something like that? Then you could just split the time front and back. I’ve not tried this but some variation like that would work well I think.

      Either way though the 14% bulbs I have work very well for both tanning and improving vitamin D levels!

      1. Hello, again! Thanks so much for replying so quickly. I’m going to trust your superior knowledge and level of experience. It looks as though I’m going to have an awesome project to complete over my district’s upcoming spring break. I’ll share some photos once everything is all done. Thanks again for the insight and inspiration.