Are there any pre-built dual stage temp controls?

I've seen one sold by a mom and pop retailer - I forget where but it had Guy Fieri style stickers on it and was about $90 IIRC. I think it used the $22 eBay STC-1000 controller and a $6 Radio Shack hobby box. If not having to do the wiring is a big deal then that's about as cheap as you're likely to find them.

If you do want to try to do it yourself it's really, really simple to do and there are diagrams on HBT.com on how to wire it. I've done two of them (one for my kegerator and another for my fermentation box) - they work great.

 

I thought the Johnson single stage controller works both ways you just have to open it and move a jumper to switch directions.

 

You can but you don't have to. I rigged mine up (basically) and outlet attached to/inside the Radio Shack box. The fridge/heat source power supply plug directly into the project box, so you don't have to mess with the guts of the fridge or get into the fridge/thermostat wiring.

Here's an example I found online from some random guy.
http://lh4.ggpht.com/_jZlSilsUoAk/TDpuP4NaCDI/AAAAAAAAAP8/l3lc5W-8dPQ/s400/DSC_6729.JPG
I don't know that the STC-1000 is rated to handle 20A, so I'm hoping that guy just had a spare 20A outlet lying around and decided to use it.

The STC unit automatically switches from heating to cooling modes (you can preset the delay, and how much you want to let it stray from the set temperature before it energizes the heat/cool outlets.

 

I've got a Ranco dual stage controller that you have to crack open and swich jumpers to change from cooling mode to heating mode.

It's a real pain in the ass.

I wish there was just a switch on the outside.

 

Ranco two stage: http://www.etcsupply.com/ranco-etc211000000-stage-p-105.html

I have this and love it. Keep in mind, if you are only running one stage at a time, that is, only heating in winter, cooling in summer, you only need a single-stage controller that can switch (for example, Johnson Controls A419), but if you want to run heating and cooling at the same time, you need the two stage controller.

ETA: I realized that I linked to the non-pre-wired version. Here's the wired version: http://www.etcsupply.com/ranco-etc211000000-stage-prewired-temperature-controller-p-110.html

Plug n play baby.

 

I doubt it's the best, but it has to be the cheapest. It's very well regarded on Homebrewtalk.com and you can't beat the price. You'd need the hobby box and the controller, a grounded plug (it could be any old grounded plug, like a power supply from an old computer, a couple of feet of wire to make the various connections/jumpers, wire nuts and electrical tape.

Here's one schematic:
http://www.homebrewtalk.com/f51/stc-1000-ebay-temperature-controller-build-330427/

 

Check out Rebel Brewer. They might have what you want. Digital Dual Function Refrigerator Thermostat
But if I understand your question your going to walk a very fine line. If either your heating or cooling isn't buffered and works too well it can take you into where you'll trigger it's counter part and it will be an never ending battle.

 

This is a really good point. You will have to set at least a few degrees span where the temperature can fluctuate up and down without having both the freezer and heater running constantly at the same time. At a certain point it's not going to be worth the cash to control fermentation temperatures if you're going to still have significant fluctuation. Might make more sense to just ferment in the house at ambient. Could you fill the freezer with water bottles or styrofoam or something during the fall and spring to help hold the temperature steady over night (or during the day) and only run the heat or the cold?

 

I use the 1-stage version of the Ranco controller (see NathanJohnson's post) because I feel like I can get by with just heating or just cooling. You can switch back and forth between heating and cooling modes with a simple toggle button. I recently just bought a third one that I got prewired; I'm in your camp on that point.

I wired the first one I got myself. I don't have a lot of experience with that sort of thing. It's conceptually very easy to follow the wiring diagram and various on-line instructions. It took patience and dexterity to actually get the thing wired so that the wires were held down tightly. Having eventually succeeded the first time, I got a second prewired unit. I wired it up and put it to work, and all was good for a short spell. Then I moved the unit, plugged it back in and I as I walked away, I heard the crackling noise of a small electrical fire. Sparks were flying when I turned towards it. The wires came loose when I moved it and shorted. I fried the electronic guts of the thing and blew $50+.

So I got the replacement unit pre-wired for an extra ~$25. And I didn't burn down the house. I learned that I'm not homebrewing's answer to MacGyver and it's OK to pay someone for skills that I lack. And that first unit that I wired by myself? It's running my beer cooler. Is it a ticking timebomb? Probably not. I hope not. I'm pretty sure its fine. I've had it for several years. Nothing to worry about, right? I don't touch it though. I don't even look at it. I have a hard time sleeping at night now. But at least I have cold beer.

 

That's the one I was thinking of - good find!

 

I have a couple of these. Love them!
Granted I don't need that second stage nearly as often, but it is nice to have.

 

Here's another option for a pre-built dual stage.

http://morebeer.com/view_product/16664