Budget Intensity Measurements Part 2: TES 1333 Solar Power Meter

Budget Intensity Measurements Part 2: TES 1333 Solar Power Meter

What is the best way to measure intensity of red light therapy panels at home? 

In our last part in this series about the Tenmars TM-206 we detailed how we have sent several cheap solar power meters to our 3rd party lab to develop correction calculators so you can take accurate measurements at home!

This time we will look at the 2nd most popular solar power meter used by manufacturers and self-styled experts - the TES 1333 Solar Power Meter!

To save you even more money, we bought the General Tools DBTU1300 Solar Power Meter on Amazon, which is an even cheaper rebranded TES 1333.


solar power meter intensity accurate recalibrate red light therapy measurement

We confirmed the TES 1333 and General Tools DBTU1300 solar power meter measure similarly, so these calculators can be used for both tools.

Correction Calculators:

Like last time, just follow these steps:

  1. Turn on the Solar Power Meter
  2. Press the "Set" button to make sure the units are in W/m^2
  3. Measure the intensity of your panel
  4. Input the whole number into the correct calculator below.
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Recalibrated Solar Power Meter for Instant Accuracy?

The TES 1333 model (including General Tools brand, but we will just call them both TES 1333 for the rest of this blog) includes an interesting feature to re-calibrate the sensitivity!

In the wrong hands, this is dangerous because we can now increase the sensitivity to display even more falsely high intensity numbers.

However, now if you want to impress your friends at parties or pretend to be a red light therapy expert online - you can re-calibrate the sensitivity lower to display instantly accurate numbers!

For example, since we know from the data the TES 1333 measures falsely high by about 2x, then we simply adjust the sensitivity factor down to 0.547 for Red+NIR. For Red-only set it to 0.83 and for NIR-only set it to 0.386 based on our data.

Here is how to re-calibrate it:

  1. The device needs to be OFF.
  2. Hold the SET button while pressing the ON button to turn it on.
  3. Release the SET and ON button rather quickly otherwise it just boots up into normal operation.
  4. When the first digit of the calibration factor is blinking is when you can make adjustment.
  5. Use the Up and Down arrows to adjust the number.
  6. Use the Right arrow to select a different digit.
  7. Press the SET button again to resume normal operation with the new calibration setpoint.

Of course there are drawbacks that this linear sensitivity adjustment does not account for the non-linear measurements that the solar power meters take.

So still the most accurate way to use the TES 1333 is use the standard sensitivity (1.0) and put the numbers into our calculators above.

What do with these calculators?

Once again you might not even need to buy your own solar power meter. If a manufacturer shows you pictures of their measurements with a TES-1333 then you can just put those numbers right into the calculator.

To be clear, the consumer should never have to measure their own intensity, similar to how you shouldn't have to measure the horsepower of your car to see if you have been scammed by an automotive dealer.

To expand on this metaphor. Lets say you got a Truck that lied about horsepower. However, you never measured it yourself and the Truck worked well for your activities for years. You enjoyed the truck and never had any issues with it. Were you scammed? If you get a red light panel that lied about intensity but you enjoy it anyway, is that a scam? Yes, of course it is.

You can note that MitoRed had extensively catalogued their intensity measurements with the Tenmars TM-206. So you should use our first calculator in the other blog to get an understanding of their realistic intensity outputs.

However, now they seem to be telling people that their advertised measurements were taken with a TES 1333. Which only reinforces how meaningless MitoRed's intensity claims really are if they can flip flop between wildly disparate tools.

Imagine if the effort manufacturers use to deceive people was applied to offering honest information instead? We could be in a golden age of red light therapy if that happened.

So look carefully at the model of solar power meter when manufacturers take pictures and videos, because it is important to use the correct calculator to get an accurate result.

How Much Intensity Do You Need?

Head back to our first blog with tips on how to re-calibrate your mindset to understand that no red light panels on the market deliver the fabled "100mW/cm^2". And that seeking 100mW/cm^2 would likely lead to undesirable results anyway.


Using these solar power meter correction calculators are the best way to take intensity measurements for yourself at home. They are cheap and easy to use, and you can finally understand realistic intensity numbers for safety and efficacy.

Unfortunately, many manufacturers and brands initially used Solar Power Meters without knowing that they measure Red/NIR wavelengths falsely high by about 2x. So they gleefully reported these unrealistically high numbers without any technical scrutiny that a real engineer or scientist would apply towards a measurement tool.

Since 2016 the so-called "experts" and consumers have only been presented with a single narrative about how ">100mW/cm^2 at 6 inches away" is the gold standard for red light therapy administration. It has established a strong bias for all consumers since this is the first and only narrative they have ever seen.

It is clear that only when these biased companies and individuals can face the truth about accurate intensity and non-contact delivery that the real science around proper understanding of dosing of red light panels can even begin to happen. Until then we will still be in the dark ages dominated by false narratives and marketing fallacies - and when that fails  - resorting to attacks against GembaRed's credibility.