Reptile & Amphibian Forums

Hi,
I have been wanting to get a good thermostat and have been leaning towards a proportional. I want it for a single RHP to heat my Prehensile-tailed skink cage. I am not sure what size or wattage of RHP, but I am guessing I will need at least a 12" by 24" RHP. I think that is over 100 watts. I am planning of buying one for Pro Products soon.

First off, do I really need a proportional thermostat for this purpose?

Which proportional thermostat would be the best one to get? I like the Herpstat made by Spyder Robotics. It seems to be the least expensive and I have heard good things about it. The Helix proportional seems to be good, but it also seems to be the most expensive. Does anyone have anything to say about the Big Apple proportional thermostat? Does anyone recommend any other proportional thermostat?

Thanks for all of the help, Josh

You may not need a proportional as long as your animal and setup are OK with the hysteresis of the ON/OFF thermostats commonly sold.

Example of an ON/OFF thermostat:
You set it at 85 deg. Heater is ON FULL until the probe senses 85 deg, then the heater is OFF. After the probe senses a drop of the hysteresis value (like 4 deg), the heater is ON full again. So the temp varies from 85 to 81 to 85, etc. If your cage is insulated, the change is slow. Usually fine for most reptiles.

The hysteresis value is usually 4 deg for the less expensive models (the $29.00 ones) and is adjustable down to 2 deg for Ranco and Johnson ON/OFF models.

Example of a proportional:
You set it at 85 deg. Heater is ON full until about 10% below the setpoint of 85 deg, then the heater is ON partially (pulsed like a dimmer) until the probe senses 85 deg. Then it stays darn close to that. Your heater is not fully ON or fully OFF most of the time, so the heating elements are not stressed as much = longer life in all probability. True for light bulbs anyway.

I have a few models including the ones you've mentioned, and all work very well. The Spyder Controls one is great. I like the analog dial of the Big Apple proportional controller (from Big Apple Herp.) Good luck.