Semi-Deep thoughts o UTH with a question.

[Boomerang]

So Most of us seem to use UTH for our various setups.
Per ZooMeds recommendation in the directions they actually say that mounting to the side of a tank is preferred over underneath the tank; No explanation for this that I could find.

I attached mine to the side because my tank was placed directly on a table and the directions say it can cause the table to fade/lose varnish or whatever.

Someone here told me that it does nothing to have it on the side because it does not affect the tanks internal heat. This is not true if you know how convection works. It heats the glass and thus provides a temperature rise to the air on the other side of the glass.
I removed the UTH from the side and immediately lost 3-5 degrees of internal tank temp from the side it was mounted to (heat may rise, but obviously a pad application of heat to the glass provided the environment with thermal difference).

I put the UTH under the tank on the cold side underneath the snake hide and the temp still remained lower overall.

So my question, figuring some of us understand how heat really works and is transferred is concerning temp measurements.

I see people putting their thermal probe under the tank, in direct contact with the UTH. How is this an accurate judgement of real time temperature if you're measuring the heat from the UTH and not what's being transferred through the glass to whatever you have on top of the glass to the snake? I just don't see how this could be accurate at all. The glass will distribute the heat as far out as it can as it is dissipating the heat (basically the way a radiator works -spread out the hot water over a large surface area provided and it cools the engine). Aren't you basically measuring the immediate release of heat and not what's being transferred?

Moving the UTH to underneath the tank did nothing for internal temps of the enclosure except lower them. Am I missing something here with this kind of application?

[aLittleLessButter]

The reason for the probe between the UTH and the glass is just for the thermostat. Thermostat probes need the most accurate reading for what the UTH is putting out, NOT what your inside temp should be. Inside the tank you keep track of temps via digital thermometer or heat gun and adjust your thermostat accordingly. To get an internal temp of 90, the thermostat may need to be set to 95 because like you said, heat is dissipated by the glass. Also there is no right or wrong when it comes to back heat vs belly heat but the UTH is not made to provide ambient temperature regardless of where it's placed. It is to provide a hot spot. Yes it radiates a bit so you will see a slight increase in ambient temps (more so if it's on a tub) but simply put, a heat pad does not put off enough power to heat an entire tanks ambient airspace. If it did, it would be a fire hazard. If you are using a UTH, you will need a secondary heat source (lamp or Che) for ambient temps and make sure you are using a thermostat

[kitedemon]

UTH are radiant heat sources. The objects they heat in turn are convection heat sources. The concern of heating from the bottom is thermal blocking and liability of the corporation. Back heat works just fine it will heat the hides and objects in the enclosure but tends to not heat the substrate, avoiding thermal blocking altogether. Radiant heaters all heat a handful of degrees 3-5 seems quite normal and reasonable. I also see about this same 'lift' in ambients with all radiant sources it is how they work. They heat objects not air the objects pass heat along by convection. A true convection heater will have a much greater 'lift' CHE and many bulbs (IR projection bulbs are an odd one) I find even typical fluorescent liner tubes to have a far greater effect than radiant source will on ambients. (5-10ºF)

The probe placement on the UTH is inaccurate. There is no way around it. The set point never matches the internal temp, most manufacturers also say not to place the probe against a power line and basically a carbon resistive element is a power cable of sorts. There is a hot debate on probe placement. Some say internal placement will be influenced by the snake and cause a run-a-way temp. I believe this can be controlled, and prevented. A thermostat probe must never move from its placement. If it does the stat cannot regulate the temp and will overheat if allowed.

If internal placement is to be used, the probe needs to be exceptionally firmly placed.

I would also suggest no high density heater ever be used in such a system, only low density elements that never exceed 100ºF. I have never seen a need for any heater ever to run beyond the 100ºF mark.

The third thing is to use a fail safe, if the probe becomes effected by animal action the failsafe would kick in.

Personally I have always used an internal placement on everything other than a rack. I set the hot spot temp I want and I get it with no variation. With the room temperature variation I see externally mounted systems have a variation that is beyond my tolerance.

There are a lot of issues with thermometers, having one that has certified accuracy and small deviation is important if you don't have an accurate set up. Either with probe placement, or the stat itself. It is common for keepers to rely on thermometers that potentially could read 4ºF off of correct (an 8ºF range).

[200xth]

I see people putting their thermal probe under the tank, in direct contact with the UTH. How is this an accurate judgement of real time temperature if you're measuring the heat from the UTH and not what's being transferred through the glass to whatever you have on top of the glass to the snake?

Does that matter?

For example (these are just sample numbers, not based on anything real): If the heat loss between the UTH and the inside, bottom of the enclosure is 5 degrees, it should permanently stay a difference of 5 degrees, correct?

Knowing that, if I want the hotspot that my snake can reach to be 90 degrees, I would set my thermostat at 95, let the hot spot the snake can reach average around 90 and be all set.

You afix the probe to the UTH (or heat tape) for the most stable, consistent temperature readings, but use a temp gun to measure the hotspot periodically, particularly when setting up the enclosure to determine the variance.

At least, that's what I do, and it seems to work out okay.

[kitedemon]

200xth The problem I have had with this method is it is not always 5º. If the room is warm it might be 2ºF but when the room cools the walls of the enclosure drop and the deviation changes. I see a variable of 5ºF up or down. At times I see only 1ºF at other times I see 6ºF. My hot spot if the probe is on the UTH the temps may range between 90-85ºF this can change in as short a space as 24 hours. I don't like having that little control. I am an odd case my room temp is unstable and changes all the time.

[200xth]

200xth The problem I have had with this method is it is not always 5º. If the room is warm it might be 2ºF but when the room cools the walls of the enclosure drop and the deviation changes. I see a variable of 5ºF up or down. At times I see only 1ºF at other times I see 6ºF. My hot spot if the probe is on the UTH the temps may range between 90-85ºF this can change in as short a space as 24 hours. I don't like having that little control. I am an odd case my room temp is unstable and changes all the time.

It was just a sample number, and yes, the variance does vary as well.

I will say something that will probably have people disagree, but I think we worry too much about maintaining perfect hotspots, or even general room temperature (at least on short term basises).

I can only speak for myself and my situation and what I've seen. I frequently have hotspots at 86 degrees. Mine seem to vary between 86 and 91. I honestly, don't care anymore, unless they are way out of whack or the heater is unplugged somehow, in which case things get too cool (obviously). I try to keep a 87 to 88 degree hotspot, but if it drops a couple of degrees (which is cooler than most people keep), I generally don't care anymore.

I've embraced the fact that this species has existed for 70+ million years, and can handle short term fluctuations in both temp and humidity. If you keep it 70 or even 75 all the time, it will end up a problem, but if the hotspot is 86 to 91 or 92, from what I've seen they do fine.

It's weird because I'm nuts about tracking snake weight and food weight (more for my information and curiosity than anything), but not nuts about keeping a strict temperature. Generally, though, mine really don't seem too concerned if the temp swings 5 or even 6 degrees. I just try to remember that even in Africa, there are abnormally cool nights.

[kitedemon]

I'll agree with you there. I am sure most of us worry about keeping things spot on all the time. For me I don't like seeing 5 or 6 degree variation in hot spot temps during one short period. It feels wrong. Temperature changes are gradual not quick and sadly I see fast changes odd dynamics of my place. But day to day morning to night large changes. I object that I cannot control the temp as much as the change. It is why after two weeks of my first snake I changed to internal and ever since. No variation at all. I can choose to change it or ramp it but I choose not my draft old wall. I am the keeper, I balance heat and humidity, not the environment I live in.

[Boomerang]

Thanks for the replies, this all makes sense.

I've had a heck of a time keeping my temps stable as well because the room temp fluctuates so much.