energy use with a johnson controller

I've got an older spare fridge in my basement right now thats not in use due to the fact that it costs alot to run 24/7. I was wondering if using a johnson controller on it and using it to ferment in would use less power than running it all the time?

i have no personal experience with johnson controllers, but one would think it should be cheaper to run. Not sure how much cheaper, though. I imagine another factor involved would be the ambient temp of the basement. If it's really hot down there then chances are it'd still have to run more often than if the temp in the basement was close to ferment temp.

Like Donner, I don't have any practical experience with this but just based on the fact that it's not operating all the time I would think it would have to reduce energy costs.

What I will add though is make sure you go through and vacuum off the condenser coils. Build up of dust and dirt on the coils insulates then and just destroys the efficiency since they can't get rid of the heat.

It will certainly use less power running part time than it would running full time, but a refrigerator should not be running full time anyway if it's operating properly. The exception might be if it were in location where it could not keep up with the ambient temperature, but that would be rare especially indoors. The real advantage of a controller is to be able to operate the refrigerator at a higher temperature than the built in thermostat will typically permit. Most won't let you run them at much above 45 F or so and this obviously would be too cold for use when fermenting ales where you want to be in the 60's usually. It won't cost much to run in the 60's so long as you aren't fighting high ambient temps. Mine hardly runs at all when my basement is in the low 70's and I have it set for the low 60's.

Johnson controller uses (literally) zero power.

Using the Johnson controller set at anything higher than 40 degrees will undoubtedly use less power than the refrigerator just running with it's own regulator.

Thanks for the answers. I'm thinking of getting one because I want to start fermenting lagers and I'd also use it for ales.

my basement is high 50's to low 60's in the winter and high 60s to low 70s in summer

passedpawn said:

Johnson controller uses (literally) zero power.

Using the Johnson controller set at anything higher than 40 degrees will undoubtedly use less power than the refrigerator just running with it's own regulator.

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+1 on this

I use a Johnson Controller on my fermentation cabinet. It uses no power at all itself, it slaves out the thermostat control to the Johnson controller box. What is using the energy is your fridge/freezer compressor.

I shouldve asked if the compresser is on a lot less when using a johnson controller.

Yes, the compressor should run less if you have the controller set above the minimum of the refrigerator thermostat which should be the case if you are using it as a fermentation chamber. I can't think of a situation where using a controller could make it run more than it would without one. The typical configuration for cooling would have the refrigerator thermostat set on max cold and the controller would shut down the compressor at whatever temperature setting you chose.

BeerPressure said:

I've got an older spare fridge in my basement right now thats not in use due to the fact that it costs a lot to run 24/7.

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Based on your description, it sounds like the fridge is on its way out. No external controller can fix a failing compressor.

You'll have it set at a higher temperature than normal, even for fermenting lagers, so it will run less. If you use it for lagering though, it will be much the same as using it as a fridge.