Infrared Temp Guns - NECCESARY, but MUST BE CALIBRATED - Here's how!

[dakski]

Frequent contributors on this site and also those with experience who post (or both) are always talking about using IR temp guns for accurate ground temps.

They are are a must. Thermostat probes can be off and only get air temp (except for UTH where they can read off the UTH - but it's under the tank, not in the tank), and normal thermometers with or without probes also only get air temps.

If you want to know what temp your reptile is actually at, you need ground temps. This can accurately be achieved with a temp gun. They range from about $14 to $200 and you can get them at home depot, amazon, etc.

Here's the thing that many people do not know! YOU MUST CALIBRATE YOUR TEMP GUN and pretty much every time you use it.

Temp guns, can be off, and may not give you an 100% accurate temperature.

First, a few rules for using an IR temp gun:

1. Calibrate the temp gun before use (see below for instructions).

2. Try to shoot the IR beam straight down from the where the beam comes out of the temp gun. Don't do at an angle, or far away either. Try to put the temp gun with the beam facing straight down close to and with a consistent distance from the area you want to read.

Again, consistency is key and as little angle and distance as possible. You can hit the same spot at 2 inches and 2 feet and you will see they read differently. BE CONSISTENT with DISTANCE and ANGLE!

3. When reading temps in a tank, take multiple readings in each zone throughout the temp gradient (hot side, ambient, cool side). It takes about a second to get an accurate reading. My tanks are mostly 6X2's and I get 3 readings on the hot side (bang, bang, bang - front to back), 3 in the middle, and 3 on the cool side. It takes about 15 seconds a tank to do this. Heat tape, UTH, etc. can create different contact points and different temps (slightly) throughout them. For example, in my BP's tank, she has a RHP and Heat Tape on the hot side. The tank is 2FT deep and the heated area about 1-1.5FT wide. I hit the middle of that zone at the front of the tank (not under RHP) and it reads about 87F, in the middle it reads about 88F, and in the back, fully under the RHP and over the heat tape, it generally reads 88-89F.

4. Always take multiple readings in each spot, especially when first using the temp gun.

You can hit spot A when you first use the gun and it can read 82F. 2 seconds later you can hit the same spot at the same distance and get 78F. Not sure why, but it my experience, temp guns can need 2-3 "shots" to dial in. Once I've used a few times, it seems to be ready to go. However, first pull with my gun(s) often read much higher than they do 2 pulls later. When I get a consistent reading; 77F, 77F, 77.3F, etc. I know it's ready to roll.

​How to Calibrate a Temp Gun:

Calibrate that temp gun by shooting the beam at your room thermostat (or reliable thermometer) and adjusting accordingly.

If room thermostat reads 70F and the temp gun reads 71F, subtract 1F from whatever reading you get from the temp gun. Shoot the thermostat at the same distance (as close as possible) as you shoot the ground of the enclosure. Try to keep the beam as straight as possible (up/down) and avoid long distances or angles, if possible.

This works conversely if the temp gun reads low. If the room temp is 70F and the temp gun reads 68F, you would add 2F, instead of subtracting.


Why do I have to do this?

Simple, and again, temp guns can be off and can vary by how much. You need to know on that day how off (literally in degrees F) your gun is that day.

I have an $81 Raytek MT6. Top of the line temp gun. It consistently reads 3-4F high. Before using it, I hit a reliable thermometer in my house. Today, the thermometer read 72.5F in the reptile area. I hit it with the temp gun and the temp gun reads 76F. When I shot in the tanks today, I subtracted 3.5F from each reading.

In other words, 93F on my BP's hot spot, is really 89.5F (93-3.5F).

It's very important to calibrate so you do not overreact and make adjustments that aren't needed, or too drastic an adjustment, to your reptiles temp.

Also of note, when adjusting temps, do so very slowly. Adjust thermostat (MANDATORY ON ALL HEATING ELEMENTS) 1F at a time, or at most, 2F.

Why get an expensive temp gun?

I am not sure. I paid $81 for mine and it's consistently off. However, it's consistently off by 3-4F (reading high). Maybe I paid for it to be consistent at being off?

We also have a $14 temp gun for Esmeralda, our Leachie, who lives in Katies office and temps are not as important to her since she lives happily at room temp.

Today it was off 2.5F. Who knows?

Frankly, if you calibrate properly, and before use, you should be good to go with any IR temp gun, IMO.





Please feel free to add to this thread and/or comment.

This is my personal opinion from using temp guns for years and owning 8 reptiles in 7 tanks currently (plus Esmeralda - who technically is Katie's) and keeping reptiles for over 20 years.

My hope is that this helps keepers to use temp guns and to use them properly.

[Godzilla78]

Dual laser temp guns are far more accurate as the dual laser compensates for distances measured, much like binocular vision.


Sent from my iPhone using Tapatalk

[Godzilla78]

How do you know that your temp gun is off or your thermometer you read with the temp gun is off?



Sent from my iPhone using Tapatalk

[Bogertophis]

dakski, your post is very interesting, as my temp. gun (about $30) often gives different readings a few seconds later, so I usually have to repeat it to get an
accurate read...glad it's not only mine. Nowhere in the package instructions did it mention all that you did either, so thanks!

[jmcrook]

I’ve always calibrated my temp gun by measuring the temp of a glass of ice water. It should read 32*. If your temp gun doesn’t show 32* for a glass of ice water then it is inaccurate by however many degrees it reads above or below 32*


Sent from my iPhone using Tapatalk

[dakski]

How do you know that your temp gun is off or your thermometer you read with the temp gun is off?



Sent from my iPhone using Tapatalk

Good point. Historically, analog mercury thermometers are the most accurate and in a room with stable temps, will give the best/most accurate reading. If the temp is constantly changing (hopefully not in your living room), that's another story as they do not adjust as quickly as a IR temp gun.

That's why I use my home/room thermostat and shoot it with the temp gun at the same distance as I measure in the tank. However, I also have a digital thermometer in the room, and the discrepancy between how off the IR Temp Gun is on one versus the other is usually de minimis. So, now that I know that, I can pretty reliably use either one.

Is it perfect, no, but I still wouldn't rely only a the temp gun by itself for temp measurement without some basis for how on the ball it is. Try two different temp guns on the same spot back to back. Do you get the same reading?

[dakski]

Frequent contributors on this site and also those with experience who post (or both) are always talking about using IR temp guns for accurate ground temps.

They are are a must. Thermostat probes can be off and only get air temp (except for UTH where they can read off the UTH - but it's under the tank, not in the tank), and normal thermometers with or without probes also only get air temps.

If you want to know what temp your reptile is actually at, you need ground temps. This can accurately be achieved with a temp gun. They range from about $14 to $200 and you can get them at home depot, amazon, etc.

Here's the thing that many people do not know! YOU MUST CALIBRATE YOUR TEMP GUN and pretty much every time you use it.

Temp guns, can be off, and may not give you an 100% accurate temperature.

First, a few rules for using an IR temp gun:

1. Calibrate the temp gun before use (see below for instructions).

2. Try to shoot the IR beam straight down from the where the beam comes out of the temp gun. Don't do at an angle, or far away either. Try to put the temp gun with the beam facing straight down close to and with a consistent distance from the area you want to read.

Again, consistency is key and as little angle and distance as possible. You can hit the same spot at 2 inches and 2 feet and you will see they read differently. BE CONSISTENT with DISTANCE and ANGLE!

3. When reading temps in a tank, take multiple readings in each zone throughout the temp gradient (hot side, ambient, cool side). It takes about a second to get an accurate reading. My tanks are mostly 6X2's and I get 3 readings on the hot side (bang, bang, bang - front to back), 3 in the middle, and 3 on the cool side. It takes about 15 seconds a tank to do this. Heat tape, UTH, etc. can create different contact points and different temps (slightly) throughout them. For example, in my BP's tank, she has a RHP and Heat Tape on the hot side. The tank is 2FT deep and the heated area about 1-1.5FT wide. I hit the middle of that zone at the front of the tank (not under RHP) and it reads about 87F, in the middle it reads about 88F, and in the back, fully under the RHP and over the heat tape, it generally reads 88-89F.

4. Always take multiple readings in each spot, especially when first using the temp gun.

You can hit spot A when you first use the gun and it can read 82F. 2 seconds later you can hit the same spot at the same distance and get 78F. Not sure why, but it my experience, temp guns can need 2-3 "shots" to dial in. Once I've used a few times, it seems to be ready to go. However, first pull with my gun(s) often read much higher than they do 2 pulls later. When I get a consistent reading; 77F, 77F, 77.3F, etc. I know it's ready to roll.

​How to Calibrate a Temp Gun:

Calibrate that temp gun by shooting the beam at your room thermostat (or reliable thermometer) and adjusting accordingly.

If room thermostat reads 70F and the temp gun reads 71F, subtract 1F from whatever reading you get from the temp gun. Shoot the thermostat at the same distance (as close as possible) as you shoot the ground of the enclosure. Try to keep the beam as straight as possible (up/down) and avoid long distances or angles, if possible.

This works conversely if the temp gun reads low. If the room temp is 70F and the temp gun reads 68F, you would add 2F, instead of subtracting.


Why do I have to do this?

Simple, and again, temp guns can be off and can vary by how much. You need to know on that day how off (literally in degrees F) your gun is that day.

I have an $81 Raytek MT6. Top of the line temp gun. It consistently reads 3-4F high. Before using it, I hit a reliable thermometer in my house. Today, the thermometer read 72.5F in the reptile area. I hit it with the temp gun and the temp gun reads 76F. When I shot in the tanks today, I subtracted 3.5F from each reading.

In other words, 93F on my BP's hot spot, is really 89.5F (93-3.5F).

It's very important to calibrate so you do not overreact and make adjustments that aren't needed, or too drastic an adjustment, to your reptiles temp.

Also of note, when adjusting temps, do so very slowly. Adjust thermostat (MANDATORY ON ALL HEATING ELEMENTS) 1F at a time, or at most, 2F.

Why get an expensive temp gun?

I am not sure. I paid $81 for mine and it's consistently off. However, it's consistently off by 3-4F (reading high). Maybe I paid for it to be consistent at being off?

We also have a $14 temp gun for Esmeralda, our Leachie, who lives in Katies office and temps are not as important to her since she lives happily at room temp.

Today it was off 2.5F. Who knows?

Frankly, if you calibrate properly, and before use, you should be good to go with any IR temp gun, IMO.





Please feel free to add to this thread and/or comment.

This is my personal opinion from using temp guns for years and owning 8 reptiles in 7 tanks currently (plus Esmeralda - who technically is Katie's) and keeping reptiles for over 20 years.

My hope is that this helps keepers to use temp guns and to use them properly.

I wanted to add something here.

I went to Home Depot today and for $3, bought a proper thermometer. Analog, not digital, but supposedly pretty accurate as it relies on a chemical reaction, not a probe sending digital signals.

I nailed it to the wall next to the reptile tanks. Because it's analog, it's hard to read except for even degrees (as opposed to 1/2 degrees), but I used to check my digital thermometer and my temp gun.

The digital thermometer said the temp gun was off about 3 degrees (Fahrenheit). The analog thermometer showed the temp gun off 1.5-2F instead.

My point is two fold and in response to Godzilla78.

1. Spend $3 and get an accurate thermometer from the hardware store (link from Home Depot below) to base/calibrate your temp gun with.

2. Temp guns still need to be calibrated and should not be relied on verbatim.

Link to thermometer at home depot: https://www.homedepot.com/p/AcuRite-...SBA2/100659742

[Godzilla78]

Yeah I agree with you Daksi, I have been keeping mercury thermometers for a long time. Very accurate and MUCH cheaper then the digital junk that runs out of batteries, and gets ruined by water!

Mercury thermometers and dual laser temp gun works perfect for me.

[SVT Wylde]

I just bought a Fluke 62 MAX temp gun and it's spot on. It's within 0.2 degrees of my home thermostat and that's good enough for me.

Some temp guns have an adjustable emissivity and 0.95 is a good setting for our hobby. If your gun is set to 0.80 it might read a few degrees off.

[Reinz]

There is something to keep in mind when calibrating with your wall thermostat.

The glass/plastic viewing window is reflective. And even the bezel is reflective on mine.

This reflection can really throw readings off. I just now shot my Tstat with the temp gun and got a 11 degree higher reading. If I had three hands I would take a pic of that.


As you see, there is a reflection of me in the window.

One time, 3-4 years ago I got a 33 degree differential. I have 4-5 temp guns from when I used to have tanks scattered all through the house. And of course I keep the high dollar one in the shop. All reflective readings are skewed with each gun.

Funny thing is the el cheapo is the most accurate of all of my guns. I sure am glad prices have come down since I bought my first one 11 years ago.

Anyway, my remedy is simple, I just shoot the wall next to tstat and I get accurate readings that way.

I just wanted to bring this up for those that were unaware of the potential reflection problem.