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thermostat vs rheostat

E

ernie55

New member
I have been told by the place I bought them that ultratherm uth did not need a temp control device. That is not so, as mine got too hot. Going to have to get a thermostat or rheostat. How does a rheostat work? Which is cheaper?
Got 2 okeetee's from SMR, one an extreme male the other a non extreme female. Thanks!
 
Lamp dimmer/rheostat: These decrease the current to the UTH, lowering the temp. They do not measure the temp, so you have to fiddle with them when the room temp changes.

On/off thermostat: you set a temp, usually with a dial. The stat measures the temp and turns the power supply off when it reaches the set temp (but the UTH temp will continue to rise a degree or two) and then the stat turns the power back on when the temp falls below a certain level. There is some swing in high/low temps, about 2-4 degrees of what you have set. You do not have to change your setting if the room temp gets warmer or cooler. The one I would recommend would be the Alife thermostat, available from The Bean Farm. Under $30.

Proportional thermostat: You set a temp, usually digitally. The stat increases the power to the UTH to raise the temp, but decreases the amount of power supplied as it nears the set temp, so the UTH does not go way over the set temp. When it reaches the set temp it stops supplying power, and when the temp drops to .5F of what is set, it turns back on, usually supplying 10% of the available power, increasing to 30%, 50% or even 100% depending on how fast the temp of the UTH is falling. This stat will keep the temp within a degree or two of what you have set. You do not have to change the setting if the room temp changes. The one I like is the Herpstat basic model, just over $100, or the Herpstat ND, about $125-135, which has more bells and whistles, such as a high/low temp alarm and a replaceable fuse. The owner of the company, Spyder Robotics, is a member here. Herpstat has EXCELLENT!!!!! customer service. This is the only kind of thermostat I would choose, because I want accurate temps, no fiddling with it, just set and forget, and reliability and technical support.

The third component of the heating triangle is the probed thermometer. This is important because if you purchase a decent thermometer, it will be more accurate than the cheaper thermostats, and you will set your rheostat or on/off thermostat according to the reading on the thermometer, not the stat. It will also give you a warning should the stat probe become dislodged and the stat behave erratically. You can also tell at a glance if your UTH has failed (which they do, occasionally).
Click to expand...

In terms of Price a Rheostat is probably cheaper, and you can also just get a standard lamp dimmer (which is what a Rheostat is) from Walmart, Home Depot, or someplace like that.
 
Also you WILL NEED a thermometer to measure the temp. A digital one with a probe is best and do NOT get the stick on ones or the analog ones.
 
Rheostats are really cheap. Like $10 or less at any hardware store. It is just a light dimmer switch. It is a proportional controller that only allows so much power to the item on the other end. It's biggest drawback is that it has to be self regulated as temperature fluctuate in your house (this depends on the location, as some rooms have little fluctuation). A thermostat can be proportional control as well or on/off control. Both units will have a probe that you put near the heat source to control the temp. The on/off will fluctuate between its setpoints as it heats and cools trying to maintain the temp you input. The proportional thermostat will will self regulate temperatures of the heat source to maintain the input temp you put in as the setpoint. You have to figure which will work best based on your location. But usually the more sophisticated the controller the more you pay.
 
Whew! So glad I don't have to retype that! Look at this thermostat. You may be able to find or make something cheaper, but this is a simple, reliable device that will save you from the fairly frequent adjustment that a rheostat/lamp dimmer requires.

I have not experienced a failure with this device (yet).
 
If you need a quick temporary fix, you can put a heavy ceramic tile over the UTH. That cuts the heat down and makes it safer while you wait for a better device to be shipped.
 
I picked up a $2 extension cord and a $4 doller dimmer (My first one I picked up the more expensive ones, second one I went cheep haha) and put the dimmer in line of the extension cord. Thats what I use to control my UTHs and so far works fine. How ever if your homes temp goes up and down you will have to adjust it once in a while. I Mine usually don't change to much unless my house goes up or down at least 5 degrees Fer. Now thats not to say it will work as well for you, but so far it has worked fine for me.
 
I have my snakes in the basement, where the temperature stays fairly constant. Rheostats work fine in this case, and are cheaper.

Thermostats are more expensive, and can get quite pricey for fancy ones ($300+).

If you have temperature fluctuations, get a thermostat. I would buy one in the $30-50 range if you are looking for cheap.
The more expensive ones will record lowest and highest temps and let you vary the temps for day vs. night.
 
ernie55 said:
Think I'll run to Lowe's & get a lamp dimmer & try - maybe later the alife on off thermo.
Click to expand...

These are what I use, I have 6 corns, and once in a while I have to adjust the slide on the dimmer. What you are looking for is a dimmer with an electrical outlet on one side (to plug the UTH into) and a cord with plug to plug into a wall socket. Before you get your snake take 2-3 days to fiddle with it to make sure you have the right temps. I found that my slides usually are correct right in the middle, so slide it there, wait a few hours and check the temp.

Here is what I bought, you can get them quick at Lowes or HD, I order mine off of Amazon.

http://www.amazon.com/gp/product/B0000BYEF6/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
 
I got two second hand Zoomed reptitemp rheostat deluxe 500s off ebay for about 34 dollars total. They can each fit two UTHs. I have the 40g on one, since it's mat is too big to couple with the smaller ones (one or the other will be too hot or two cool because of different wattage requirements). The two 15s are hooked into the same rheostat; they have a slight difference of a few degrees, as one is slightly bigger than the other, placement on the glass, and small difference in vertical placement. Before I moved them, one was about 2.5 feet off the floor and the other was about 8 inches from the floor, and had a very noticeable difference in temperature.

Now that they moved across the room and are closer to being level, it's easier to keep them both within a few degrees, both inside the optimal temps for corns.

All the tanks have their own digital probed thermometers placed over the hot spot, and I rarely adjust them, pretty much only when I have my window open or there's a big fluctuation in ambient temperature. I might bump it a couple of degrees when digesting if the ambient temps bring them down to 80 instead of 83-86. Otherwise they are hands-off for me. It took some time to get them adjusted to their best setting, but otherwise, they are great.
 
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