Raising ambient temperatures

[towelie4365]

So I'm considering using flexwatt heat tape to raise the ambient temperatures in a rack as opposed to using a space heater.

Would I be able to use 12" flexwatt (23 watts/ft) with 4" flexwatt (6 watts/ft), and have the thermostat probe on the 4" flexwatt maintaining 95F (or whatever I need for a hotspot), and simply use a dimmer switch off the thermostat output to control the temperature of the 12" flexwatt? (12" will maintain ambient temperatures) Both would be connected to the same thermostat, regulated by the temperature on the 4".

[The Serpent Merchant]

Flexwatt and other UTH's do very little for ambient temperatures. They are designed to transfer heat through conduction not convection.

Further you cannot put 2 different sizes/wattages on the same thermostat. That is asking for disaster.

[jedidiah578]

I have thought about something similar using 2 strips of heat tape to maintain a hot spot & cool spot temps. I don't think its a bad idea but the 2 strips would have to be controlled independently. I would think if you used a herpstat 2 it might work fine.


Where are you planning to put the 12" at? like the other responder said the heat tape wont really add to ambient temps. My plan was to use two strips for belly heat.

[kitedemon]

Flexwatt and other UTH's do very little for ambient temperatures. They are designed to transfer heat through conduction not convection.

Further you cannot put 2 different sizes/wattages on the same thermostat. That is asking for disaster.

Aaron, I thought that too but was quite obviously pointed out that flexwatt is a radiant heat source. 'calorique radiant heat systems' in either event it still is not convection and does not heat air well.

The set up you are describing is actually what I use I have 4 inch for the hot spot and the low wattage 17 inch for the cool area. I need to use a herpstat pro (herpstat 4) to control it. I also found the the top and bottom due to the cool room temps very different (10º) So I needed to heat the top 3 and bottom 2 separately. Why the 4 tstat probes to control one rack. Top and bottom warm and cool. This however only added a few degrees to the air temps adding insulation added a few more. The kicker for me is a huge amount of effort but it added 5 or more degrees.

Where the tub slides on all but the bottom, a routed a channel 1/8 deep and wide. I marked where the tub sits and from about 2 inches from the back to the same on the front this is how long the channel is. At the ends of the channel I drilled a hole through. In my case the 'shelves' are 1/4 thick so I had to redesign all of them to take a thicker material and change the rack body to work with it. I have 3 channels on each layer. The open top is covered with Al tape the flexwatt is over that. The openings to the channel are the two holes from the lower layer air can circulate though the channel become warmed by the tape and exit mine runs well enough that you can feel with a wet finger the air moving. As the flexwatt is regulated the air temp varies with it as well.

It can be done but is not a easy solution. The simpler solution is to heat the room and if this proves to be far too costly (mine is) I might give thought to giving up on the rack all together and using an enclosure system that has other heating options aside from strictly radiant heat.

[PitOnTheProwl]

Flexwatt and other UTH's do very little for ambient temperatures. They are designed to transfer heat through conduction not convection.

I keep seeing this and then I o back in my snake room and check my hatchling rack.
Back heat is keeping it a 91 degrees in an 80 degree room.
I don't know where it is conducting through as the tubs are not touching the tape at all?

To the OP, You would need two thermostats as the back heat will need to run hotter than the belly.

[snakesRkewl]

The flexwatt touching the tub will transfer plenty of heat into the tub.
My room is about 75 and my hot spot is 95 and my ambient temperature is about 87 on the warm end and 78-79 cool end.
If the flexwatt isn't creating that 87 degree ambient temperature then what is and why is the cool end of my tubs 3-4 degrees warmer than the rooms ambient temperature?

If it was that cold in a room I'd use 4 inch for the ambient under the cool end and use 11 inch under the hot spot and control them with 2 thermostats.
I'd also be using closed racks or enclosing them if I had open design racks.

[kitedemon]

The flexwatt touching the tub will transfer plenty of heat into the tub.
My room is about 75 and my hot spot is 95 and my ambient temperature is about 87 on the warm end and 78-79 cool end.
If the flexwatt isn't creating that 87 degree ambient temperature then what is and why is the cool end of my tubs 3-4 degrees warmer than the rooms ambient temperature?

If it was that cold in a room I'd use 4 inch for the ambient under the cool end and use 11 inch under the hot spot and control them with 2 thermostats.
I'd also be using closed racks or enclosing them if I had open design racks.

Jerry and Rob I see what you are saying. Radiant heat heats objects that then will heat air This is you 87º being heated by the substrate/hide tub sides ect. Agreed. My point is this if flexwatt directly heated the air the whole thing would be close to 90 with no cool end at all. To my mind the ambient temp in Jerry's example that is indirectly heated by the flexwatt is 78-9 only 3-4ºF over ambient that is about what I'd expect. In my case with ambient room temps averaging 63-66º this time of year 3-4ºF isn't doing much of anything.

Perhaps it is a definition of very little for me less than 10% is very little if it is under 8ºF increase it is very little. If Flexwatt could raise ten degrees to the air there would be no gradient possible with out a cooler system.

Radiant heat heats things not air. This is why it is used in skating rinks and out door cafes in the winter. Tt heats the humans sitting under it but not the air so it is efficient to use for this purpose, unlike having a forced air system to heat something like a rink is crazy and counter productive.