Read this and weep all you eco enthusiasts. Want to really be “green” and cut your power consumption massively? Then you need to think a little outside of the box and do something about that power hungry tall white box in the kitchen. Let the self sufficiency website be your guide for the day.
This article will tell you how to drastically cut down on your daily electricity costs and how to convert a chest freezer in to a fridge. You won’t break the warranty, you don’t have to touch any of the inner workings of a freezer to turn it in to a fridge, and the surprising thing that we have found is that a top opening fridge is actually more convenient. First a little background:
Why Turn A Chest Freezer In To A Fridge?
We run off solar so we have always used a gas fridge. It has a small freezer compartment and a standard sized fridge compartment. It has been giving off black fumes now and then for a while and the thermocouple is also broken. It was very expensive to run but we thought there was no alternative as conventional fridges, even A plus rated ones still consume vast amounts of electricity, much more than our system will supply.
The answer is to have a fridge that uses nominal electricity and will not consume all our electric needing us to turn on a backup generator.
And we found the perfect solution. Converting a chest freezer in to a fridge.
I will get to the power consumption in a minute but first let’s see why using a chest freezer as a fridge is such a good idea.
Why Chest Freezers Are So Energy Efficient
The fact is that chest freezers are super insulated. Designed to keep items frozen for extended periods they are so much better insulated than a fridge it is not even funny.
But the real benefit is that the lid opens up rather than out as on conventional fridges and many freezers. Why is this so much of a benefit?
Cold air sinks.
So when you open your fridge or upright freezer all the cold air falls out and it then needs to consume lots of power to get the temperature back down.
With a chest freezer you open the lid up. No cold air falls out, rather it falls to the bottom. This means you lose less cold air and it will not need to consume much electric to get the temp back down.
How To Do A Chest Freezer To Fridge Conversion
Basically we need to override the settings on a chest freezer so that it never freezes. We need to control the temperature so that it cools only as much as a normal fridge does.
After some experimenting I have set our chest freezer to maintain a temperature between 3 and 6 degrees. This seems about right and it means that the compressor seems to hardly ever run if the fridge is not opened.
It can be hours between when it kicks in for a minute or two to maintain the temperature.
How to do it.
Well, we are in Spain which meant I finally sourced a simple temperature controller from the UK. The company were helpful with my questions and as a way of saying thank you you can buy the controller very cheaply from them (see the resources at the bottom of this article). What you then do is simple. Get an extension lead and cut the wire. You then simply wire in the little temperature controller to either side of the cut wire.
Plug the freezer in to the lead which runs to the controller and then this plugs in to the mains. No messing with the temperature sensor of the freezer itself, everything is external. No voided warranties or anything like that. There are loads of settings on this gadget and one important one is that you can set a delay ( I set it to 10 minutes) for how immediately the compressor kicks in when it reaches the higher temperature. This will prolong the life of the motor.
For those in the US you have got a real easy job. Amazon sells a simple plug in device (see resources below). You don’t need to do any wiring at all. You simply plug in your chest freezer to it and set the temperature range.
I wish I could have found one for ourselves but it was no biggie doing a little wiring anyway. Both devices have a temperature sensor that needs to be placed in the freezer. I could not get ours through the drainage hole as it has a solid end so it goes in over the top. It doesn’t seem to have affected the seal so it’s all good. I taped it to the side at about midpoint to get an average reading of the temperature in the fridge for the controller.
How Much Does My New Fridge Consume?
We bought a brand new A plus rated Zanussi chest freezer of 260 l capacity, which is the same as our old Gas fridge and more than adequate. It consumes daily between about 150 and 180 watts, give or take a few. If you want to get all fussy as I know some do and I am always getting told off here for mixing power, energy etc the new fridge consumes 0.15KWh to 0.18KWh in any given 24 hours. Did I write that correctly? There is obviously a range depending on how often the fridge is opened but that is a pretty amazing set of numbers as far as I am concerned and for average daily use it is closer to the lower figure. This is in April of 2010 in relatively warm Spain. I imagine it will increase a little as the external temperature increases.
The beauty of the external temperature controller is that you can set the desired range very easily and it displays a readout so you can see how cold or hot the fridge is.
I also used a plug in meter so that I could see how much the new chest fridge consumed and these are definitely a handy device to have anyway. You can then easily see just how much power any device consumes in any given period. And if you are on the meter you can program then with the price you pay for your power so that you can see how much it costs you. See the resources below to get this very handy gadget.
Try one on your fridge that you currently run and you will be rushing out to buy a chest freezer and external temperature controller pretty soon. But is it all roses?
It’s pros and cons time.
Pros To A Freezer To Fridge Conversion
- It easily allows those with minimal solar systems to run an electric fridge rather than expensive to buy and gas guzzling gas fridges. Our new chest freezer was actually half the cost of our Gas fridge. And that is for an A plus rated Zanussi!
- Surprisingly it is actually more convenient to use. The lift out trays and the depth for storing bottles upright (it’s vino o’clock) make it easier than trying to find things at the back of a conventional fridge shelf
- Super energy efficient, it uses what a normal 100 watt bulb would use in less than 2 hours
- Lowers the carbon footprint, especially if you run a solar system
- Very easy to do the conversion
- If you desire it is simply a matter of unplugging the chest fridge from the extension that is wired in to the temp controller and you then return it to a conventional chest freezer if you plug it directly in to the mains
What is Bad About This System
- It means there is no freezer box
- You need space to lift the lid up
- The chest freezer needs more width than an upright for the same internal space
- You have to do some wiring if you are outside of the US, but honestly it is a matter of a few wires
- It makes you totally paranoid about how much power your appliances consume (not actually a con if you ask me)
Final Thoughts And Resources
What I do find rather amazing is that there are no commercial fridges available that have a similar level of insulation. Chest freezers by design are super insulated so why not use more insulation in conventional fridges to lower their consumption. It may bulk them out a little but worldwide it would save humungous amounts of energy.
And for that matter why is there not a plethora of funky designs for fridges with doors that open up rather than out. So much power is consumed each time we open a conventional fridge as the cold air floods out. I mean, we can design all manner of funky gadgets to close kitchen cupboards slowly, automatically lower loo seats etc etc. You can’t tell me someone could not design some cool gizmo for a fridge that had a door on the top that would then also raise up the trays . But really it is not that inconvenient anyway.
If You Want To Be A Copycat
Below I will list the items you will need if you want to do something similar and get the most energy efficient fridge it is possible to have. I will put UK and US resources below so it is an easy way to allow people from those countries to see what they need. I would seriously recommend that you buy a meter that allows you to read how much energy your current appliances consume. It will probably be a real eye opener for a lot of people.
Energy Meters to measure power consumption Very useful indeed
Johnson Controls Manual Thermostat Control Unit A simple plug and play device. No wiring for you lucky US folks. Simply plug in a freezer, set the dial to the temp you want and you are good to go.
Energy Star Chest Freezers Get ready to save some serious watts.
The digital thermostat package I bought. Now available from Amazon at a third of the price we paid! A few UK pounds gets you the abilty to change any freezer in to a fridge. Magic.
Efergy Esocket Plug-In Power and Energy Monitor Smart Meter 8 pounds allows you to monitor your appliances power consumption and see how great your new chest freezer is. Well worth having.
Discount Chest Freezers Get a high rated one to start on the right path but if you already have an old chest freezer then give it a go with that.
I hope you have found this interesting. I must say I am VERY pleased with the results. It works like a charm. Runs on minimal power and means we don’t have to buy as much gas. And it really is actually easier to use a fridge with a lift up lid and lift out trays than a normal fridge, which is not what I was expecting at all.
It’s like living in the modern age but cheaper. I still find it odd hearing the hum of an electric fridge after five years with a gas one. But I am not missing lugging big red bottles in to the house every 3 or 4 weeks. And we have an extra cupboard now as well.
Ooh yes! I want to be a copycat! I will be passing this on to my technical department (aka long suffering partner!) Thanks for great info and a literally very cool post.
It is definitely worth doing. I have even heard of people having good results using second hand chest freezers rather than new A rated ones. Not as efficient but still much cheaper than using a conventional fridge. Get the tech department on to it, it was a very quick job to do.
Thanks for that Jeff. Nice to have some more technical info, it is never my strong point. The energy meters really are well worth the price. I wish I had bought one years ago rather than to just confirm the new chest fridge really was using minimal power. I think if everyone plugged a fridge in to one they would be considering doing a conversion.
Another thing to put on my to-do list.
As you mentioned chest freezers are certainly better insulated, but more important is the fact that they also have the condenser tube wrapped all around the outside of the cabinet to dissipate heat more efficiently. This also helps eliminate the problem of condensation around the lid seal gasket. In a conventional refrigerator/freezer an energy wasting heater strip is used around the lid or door seal to keep condensation from forming and freezing the door shut.
I’ve been using one of those Energy Watt Meters for a few months to educate some close friends about how much power they are using on common household appliances. You can verbally tell people of all the facts and numbers for the amount of energy they are using or could save, but until they see an actual number on a display does it really make them think about other options available and maybe making a few changes. It’s a great inexpensive “teaching” tool.
Thanks for another great post!
The down side to the condenser tube wrapped around the whole freezer is you can’t simply add more insulation. I’ve often wondered if one could get a cheap! chest freezer with a heat dissipation plate, so one could add 6-12″ of insulation all around and REALLY have it save energy.
Very cool! (get it?) Only I need more FREEZER space, so how do you convert um a broken computer into a freezer?
You are very clever, and of COURSE fridges should be made this way.
It is working really well still. I am afraid my technical prowess is not quite up to your request though. Sorry 😉
Here’s an idea for a cool gizmo for a fridge that had a door on the top that would then also raise up the trays . A hinged sytem like a fishing tackle box
Checking to see if y’all fell off the cliff… no updates for a while.
Regarding the freezer/fridge conversion:
I first ran into a mention of it on an Australian site about a year ago, but your mention of using a beer fridge controller is perfect (he wanted to sell homemade units for $100 AU). His selling point was that his controller ran on DC power, but I believe that the first year’s energy savings would buy a big enough solar panel and inverter to run both the controller and f/f on AC.
I like Michelle’s idea for a hinged tray lifter; there would have to be a counterweight setup and gas shocks to keep the hinges from dying and the door from slamming. I think that maybe she intended to leave a link but I’m not seeing it.
My daughter uses a chest freezer for freezer-type things; she hangs her pots and pans on the wall above it.
I’m close to San Antonio, TX, trying to do something similar to your self-sufficient life but I haven’t gotten the moneymaking thing worked out yet…
Adios for now.
Johanna, the conversion is still working great and we are loving not needing to use the gas fridge any more. The AC use for the controller is so minimal that the savings are still absolutely enormous.
I hope you continue to be more self sufficient, but yes, finding a way to support yourself is not always easy.
Thanks for the comment. Will be back soon with new articles.
this sounds like a neat idea….when I have a place of my own I may try to implement it….though if this place in question is an apartment I may need permission to do so from the complex managers
I was wondering about the electricity usage of the digital thermistor when the chest freezer/fridge is not being powered. How much does the meter itself consume. I was thinking about doing this conversion myself. I just used a kill-a-watt device on my old fridge, used 4.4KwH in a 24hr period. 🙁
I was thinking of getting this pre-wired device from amazon.
Anyone experience problems with temperature variation between top and bottom being too great or having a moisture problem?
Laura I had to use something different to that as it is for US systems but I think the usage is very minimal, my temp controller is less than half a watt so that is pretty good. Wow, the fridge you have uses a lot, you can easily get down to less than 10% of that. This unit is a little cheaper than the one you linked to but I think they do the same thing, maybe one is a newer model.
The temp difference has not been noticed by me but there is moisture in the bottom quite often. We just open the drain hole or clean it out before we put a big shop in the chest. But the main thing is it uses such little power and I actually now prefer the lift up lid design to normal fridges. Hope this helps.
Thanks, yeah that was very helpful. I just ordered the chest freezers and will be converting 1 to a fridge. Thanks for the link. I will check out that unit as well.
love this site! wish you had lots of pictures!!! dr. b
Got the freezers working like a charm. I am going to borrow the power meter from the library and get some reading. As of now the freezer/fridge is on maybe fore 10 minutes every 2 hours.
Nice one – we are sooo happy with ours, its just so efficient.
We are also in Southern Spain and run on solar power and have a gas fridge/freezer. We need more freezer capacity for freezing surplus vegetables. I’m finding it difficult to obtain a gas freezer here. Have you any ideas?
Sorry we have no experience of gas freezer’s but check out you might find you can run a chest freezer on your electric set up anyway. We have various friends that do, and we have just about managed to run a borrowed one (but only in the summer as our solar set up is smaller). Just check out confort for cheap A rated small chest freezers.
Our very old standard style refrigerator used 1600 Kw of electricity in a year (about 4.4 Kw/day), which was a total of 17.5% of our yearly household electricity consumption costing us around $260 / year.
I have run some tests on our new setup. We bought 2 chest freezers, one to act as a freezer and one which we converted.
The standard chest freezer uses on average (over a 3 day period) 0.0509192 KwH, which would be 446 Kw/Year and cost $71.37 at current rates of $0.16 / KwH.
The converted fridge is using 0.0209302 – 0.0220 KwH on average (so far only 36 hours), at it’s high end would be 193.08 Kw/Year and cost $30.89 year to run. I think I can shave this down a dollar or two as we have the temperature probe on the roof of the lid, so when the lid is open, it triggers another cooling cycle. This is partly by design to make sure everything keeps cool inside, but it most likely runs sooner than it normally would due to loss of cooling. We have a thermometer inside the fridge that almost always reads 39F. We set the temperature control device to trigger on at 40F and off at 38F. It is a very tight range that could probably be expanded a bit to allow more fluctuation. Also we might try a week of mounting the probe in the middle of the freezer to see if the temperature fluctuates much and what the energy savings might be.
So I am expecting to save 961 Kw ($153.76) a year with this new setup. We will use only 639 Kw/Year for the freezer/fridge instead of 1600 Kw with the old fridge. We spent $720 for both freezers and less than $80 for the cord + temperature controller. In energy savings alone, we will see our return on investment ($800) in 5.2 years should electricity prices remain constant, sooner if the cost increases. This doesn’t take into account the spoilage from our old fridge. With the constant temperature and minimized fluctuations, our food is keeping fresher longer, much, much longer than previously.
Thanks for such a comprehensive comment. Much better with the stats than I am ever am and it is appreciated 😉
We just have our sensor taped to the side of the freezer and I am sure that will save you a little more.
Glad to hear from someone else that has a system like ours, I am so pleased with it, especially as we no longer have to lug heavy gas bottles about the place like we did with our old gas fridge.
Homebrewers use freezers with controllers all the time. I do. One problem is since there is no frozen section there is nothing to remove moisture from the fridge freezer. This can lead to moisture problems. Normally in a freezer moisture is frozen out of the air or removed by a fan system but a freezer being used as a fridge doesn’t have that.
See thread http://www.tastybrew.com/forum/thread/138252. I and others use a open bucket of desiccant like “Damp-rid”.
Just food for thought.
Good idea, that is the one thing with fridge-freezer to fridge conversions, they do need a regular wipe-down as there is condensation. And, funnily enough after a split bag of squid incident I was starting to think a desiccant would be a good idea, and would help with smells too.
I have just popped a bowl of baking soda in there for now, but think something more powerful might be better.
I have been doing this for 3 years. I actually replace the original thermostats with a universal thermostat for a refrigerator or chiller.
After 2.5 years my first unit failed. A hole in the aluminum evaporator coil developed. I think this was a result of too much moisture prematurely corroding the coil.
As mentioned in a few previous posts, when a freezer freezes, it removes moisture. Since the converted units don’t freeze the moisture is always there.
I waiting to see if the other units fail at 2.5 years plus.
Recently purchased a new 150L chinese brand freezer for $185 US and then the freezer to fridge conversion termostat home brew for approx $60 US.
Conversion was pretty easy.
Power usage over the last 5 days averaged 98 Watts per day, yes you read that correct 98 Watts per DAY.
I made incubator using digital temperature controller. I’ll try to convert chest freezer to fridge using this concept. Thank you very much. This article is very helpful.
Hey guys I have a question, I’m thinking of doing this same thing with a remote cabin without electricity, I’m wondering what size solar panel would I need to power just the fridge freezer if I went with a small freezer (5.1 Cu. Ft.) similar to http://www.sears.com/shc/s/p_10153_12605_04619502000P?sid=IDx20070921x00003a&ci_src=14110944&ci_sku=04619502000P
I have a 90 watt panel on a 10 amp charge controller that I use on a camp trailer, would a setup similar to that be enough to power a chest fridge?
That sounds fine as long as you have good battery storage and that the sun actually shines for a decent amount of time 😉
okay, good deal, on my camper I use 2 120ah batteries, and I’m in Idaho, and would be using it mainly in the summer, where we get a good amount of sunlight (with sunrise at 6am and sun set at 10pm)
Hey this is an old thread but I thought I’d check in now that you’ve been using the fridge for a while. Any updates? Concern about moisture? Premature failure? Mostly I’d love to see a post on your organization system and why you prefer it to a regular fridge. Whaddyathink?
Hi Brad. We still love the freezer to fridge conversion. Mostly because it is a lot less hassle than a gas fridge, and uses such a small amount of electricity that our small solar system copes with it just fine. Moisture is a concern, but a good wipe out each week sorts that out. Keeping a cool box inside it provides another insulated area which is good for frozen foods for a day or so, plus another shelf for storing items!
It is more hassle to clean out than a vertical fridge, simply because you have to lean right down in there, but overall definitely a winning eco living item!
hello, the link for the uk thermostat isnt working, could you please advise where you got yourse from. cheers rob
robin it looks like they are down for maintenance, hopefully they will be back up soon. We got ours from them.
you could buy two freezers (use one broken one easier to come by)cut hole in sides run insulated duct and a fan connecting them
to kick fan on have it rigged to the temp control to kick on when temp rises above so and so
for a fridge side with a freezer side only running condenser for freezer side forced air for the refrigerated side
no premature failure
very nice article and uptodate. i was researching the same thing and came up to you. so to keep a long story short i think we should give credit for the idea where is due
this guy was the first one i found to propose such a thing
Hi, great info! well done!
I find that the UK link is still down for maintenance.
Please can you tell us what model your unit is, the picture you have posted is blurred and I am unable to read any useful information like the model number or brand.
I am going to hazard a wild guess that it is a “STC 1000″…. probably from “Elitech”?
any information would be very helpful.
sean that sounds about right. I don’t have access to it at the moment but that does ring a bell. That site does still seem to be down so I would say check out Amazon instead, I see there are a few options there.
we are living of grid with a normal frigde freezer, its an old type and uses only 130w The secret is putting a timer on your fridge that way you save your batteries during the night when it is cold anyway. this works even in the south of spain.
This is interesting as I have trying to get for years a fridge that would work fine for cheese. But why starting with a freezer instead of starting with an all fridge -freezer less fridge- that you tweak to go to higher temperatures for cheese keeping?? Some under the counter ones inside/outside will go up to 50F/10c witch is not quite perfect but closer to the preferable temperature of 55F. An other option is to use a small wine cooler that go up to 60F but those blow dry air detrimental to cheese. You can add a bowl filled with water to help but it is not perfect. I believe an all fridge without a freezer going up to 50F is the best solution. I would buy a all freezer fridge anyway.
I meant to say “I would NOT buy an all freezer”. An all fridge without a freezer is much preferable to modify; or buy one that goes up to 50F/10c and live with it. Now a few semi-commercial fridges are convertible from all freezer to all fridge. They are full size units (Frigidaire) too big for a dedicated cheese fridge for me but they may work for other people making cheese for example. In any case my experience with two wine coolers was not good. They were very noisy and consumed a lot more electricity than my big 4 doors 4 temps Samsung fridge. Putting water inside did not really help with moisture and was not good for the wine coolers.
cool idea..literaly 🙂 i was thinking the same thing and here i am reserching….. heres my thaughts when using solar panels….charge your batteries fully first befor you turn your freezer on…then use the exess/dump load to run your freezer for as long as you can…..freeze water in the bottom of the freezer if you can…..then use it unpowered like an old ice box…no thermostat required….and you are using energy that is otherwise unused….you could ague it cost you $0.00 to run.
there are power losses in converting solar into cemicaly stored energy(battery charging) so try not to use stored energy.
there is a big loss in a inverter 12v dc to 110/240v ac ..so im looking for a chest freezer that runs on dc.
Great article. I would like to do the same thing. What size/brand inverter do you have? I was told that there was a start up surge when a fridge fires up. I just want to make sure I get the right size inverter to handle the surge.
sid, we have a Studer pure sine wave 1300 which runs the house. Not a huge capacity but it is fine for just running the usual appliances. We already had this though before we did the conversion, there is a bit if a spike when it starts, but nothing too huge.
Hi just a quick question what setting do you have your freezer set to with the controller and when it is running how long should it run for? Mine runs about 15 min which seems a little long to me. Thanks…
Jason, I think ours is set pretty high (3-6 degrees), it ony stays on for a few minutes at a time. I would have a play with the temp until you get it to shut down after a few minutes. Of course the room temp will make a difference so I would try to ensure you site it in the coolest place possible.
Thanks for your reply. I’ll try your suggestions. I learned about this conversion from your site and i appreciate your time.j
This is great. Been needing a refrigerator, but trying to get into a more self sufficient life and was wondering how that would work with a electric hungry fridge. When you say that it stays at 3-4 degrees, is that C or F? I have medication that needs to be refrigerated, but can’t be that close to freezing if it’s F. I’m guessing it’s C since you’re in Spain, but I don’t want to assume and convert everything to find that it’s not going to work for what I need. I’m off now to check your site for alternative air conditioning. I like to be cold. Might just need to move up north, lol!
Hi Sam, Yes everything here is metric so centigrade it is!
hi, the link for the digital thermostat source seems to be broken – was it this type? http://www.amazon.co.uk/Temperature-Controller-Probe–Great-Refrigerator-Temperature-Controlled/dp/B007THWZJG/ref=sr_1_4?ie=UTF8&qid=1370274033&sr=8-4&keywords=digital+thermostat
or do you have the company name?
nick that does seem to be the one. Much cheaper now too, which is great. I will update the link, thanks for that.
Good Article, there are some things that should be mentioned. I’ve had a 15 cubic foot fridge and 5 cubic foot freezer set up like this for over a year.
Chest Freezers are cheaper than new upright fridges
Vegetables and fruit last way longer due to the increased humidity and relatively low temperature change
Keeps beer at the perfect temperature
Near-Endless amount of space compared to fridge of same size
When opened, cold air stays inside, does not pour out.
Have to wipe condensation alot. It’s actually not too bad, I just leave a rag next to the fridge.
Requires cleaning at least every month, I leave old towels on the bottom and change them every 2 weeks.
Food freezes if it touches the sides of the freezer with the freon cooling tubes.
Have to be crafty and “invent” containers to stack and store food; have to have multiple layers.
Have to remember what is in your fridge, it’s not all at eye level anymore
Looks like you’re hiding bodies in your kitchen.
Let me also note I do not live “off the grid”, I just didn’t see the need to buy a $2,000 french door fridge that draws unreasonable amounts of power. My fridge and freezer combined draw half of what my previous fridge/freezer drew. That may not be surprising but my previous fridge/freezer was only 14 cubic feet total, so I gained 6 cubic feet overall and half of the power consumption.
Tip: The more things in your fridge, the less it will cycle. An empty fridge will draw the most power.
I used this controller:
good idea. Anybody knows or have heard about which controllers to use in germany? we have 220-230 Volt, 50 Watt and secured with 16 Ampere.
Any Ideas, links, Forums?
Thanx in advance & geetz2All
Here is a concern from another site…I think on here vance mentions it too so I myself am nobody in the world of self sufficiency more of a dreamer but Lord willing want to get it right when I do start… correct me if I’m wrong the two cons with this method are condensation and the pipes getting corroded now if we use refrigerator pipes and whatever this guy says then should we be on a winner?
Sorry to burst your bubble on this project, but the freezers pipework is metal so when you are using it as a fridge it will keep the evaporator pipes wet and at a high pressure,normally low pressure and frozen so it won?t be long before you loose all the gas charge due to rusted out pipework, but don’t worry I’m making one for my father in law for fish in fish bins, I’m using a fridge evaporator and electronic controls and the freezers internal condensor, I will document the whole lot so every one can build one. I’m a appliance serviceman with loads of refrigeration experience so I know what I’m talking about. Just go to any appliance service centre and ask for a throw away, I landed a throw away only a week old!, I will give the photo’s to prove it. ?
I dunno if he did come back to show his work but I’m sure you guys know what he’s on about and can guide us in laymans terms n direct us to get the job right?
adam that all sounds a lot more technical and advanced than we are used to. All I can say is that 3.5 years after doing our conversion it still works. Sure, you do get a little bit of water building up in the bottom after a few weeks, but it is nothing that a little wipe down won’t get rid of. Not perfect obviously but for the non-technical a simple system that I described is a decent compromise I think.
Thanks for the info, it does show that there is more to this than you first assume if you want it to be a perfect system. But us layman have to stick together, right! 😉
waste says:January 24 at 4:46 pm very nice article and uptodate. i was researching the same thing and came up to you. so to keep a long story short i think we should give credit for the idea where is due this guy was the first one i found to propose such a thing http://mtbest.net/chest_fridge.html
I found the above comment on your blog so went and checked this guy out and sure enough he has done the same thing.
He seems like a clever guy and has written books on all sorts. Healthy living cooking etc. I can’t say I agree with everything he says about going vegetarian or vegan but he sure has some amazing ideas.
Like using bubble wrap for bubble grazing in the winter and he made it look good too?
I thought I’d ask the man himself ‘Tom Chalko’ if he had suffered any problems with the chest freezer conversion?
This is his reply;
“People use my thermostats for ~10 years and no one has ever reported problem with freezer.Tom”
Its a hobby of mine researching and thats why I try a and look at all angles and be open minded that way you can appreciate many things in life and find some amazing things that could benefit you or others around you.
So correct me if I’m wrong but is he saying that he and those who have bought his thermostat don’t get this problem at all or is he like yourselves keeping on top of the moisture issue? If so how? Is it the wiping down or?
Forgive me for prolonging the issue but you have got to do the job right.
I copied this from his website
Dr Tom Chalko holds MEngSc in Mechanical Engineering since 1975 and PhD in physics (Laser Holography) since 1979. He is an author of 3 books and numerous research articles. Prior to his retirement in 2001 he was an academic at the University of Melbourne in Australia for nearly 20 years. Since 2001 Dr Chalko focuses on setting an example of energy-efficient lifestyle, relying ~100% on renewable/sustainable energy sources and living with the minimal possible footprint on the environment. His research interests span from geophysics and astrophysics to physics of Consciousness and the Purpose of Existence.
Greetings from the north shore of Long Island NY, I want to thank you for this article and tell you your information may be the savior of the commercial hand harvest shellfish industry on Long Islands north shore. Starting this year from May 1st to September 31st NYS is requiring all oysters and clams harvested from the waters off Oyster Bay to be placed into refrigeration or iced on board to prevent the growth of vibrio. This past month I was contacted by a fellow member of the North Shore Baymen’s Association to research mobile reefer units online for possible use on our small boats of 19 to 25 feet to comply with the new requirements and was shocked at the of prices $6000.00 and up, plus we would need to custom build coolers. Then somehow I found your website and realized from your information that we could use off the shelf chest freezers ,the Johnson controls and a small generator to create affordable refrigeration for on board use that would not take up much space and weigh under 200 pounds. We estimate the average clam digger using this setup will spend well under $1000.00 , final cost would be determined by the size of the freezer and generator purchased. This will be a trial and error thing, over time we will have to work out the kinks such as durability with proper weatherproofing, but we will be happy if we can get a season out of the setup. We have put together a pamphlet on how to do it and are now in the process of spreading the word among our fellow baymen. Once again thank you for this valuable information you have provided!
Thank you so much for making this article. I just bought the Johnson Digital controller. I bought a chest freezer for a home kegerator and was ready to ditch it for a mini fridge because I couldn’t get it to maintain non freezing temps. Great review and how to! Thanks again.
I picked up a Haier 148 litre chest freezer with a 3.5 star rating… which for the time being is about as high as they go….
And in lieu of a wiring and thermostat conversion / addition / modification – I just turned it to the highest “freezer” temperature, which is about -5*C, and added a Kambrook mechanical timer, and that switches in for 15 minutes per on switch.
So I figure that running it at an average on time of about 30 minutes a day, in two sessions, ought to keep it all just fine… It might need 2 or 3 x 15 minutes in summer and perhaps 1 x 15 minutes in winter….
Because the bottom is an odd shape, I might stick in 2 x 20 liter water containers to fill the bottom odd space, then a level bottom shelf and a small 12V circulation fan, to pump the warmer top air, down to the bottom, past the water tanks.
A year down the road… $60 Johnson Controls A419 temperature controller (familiar with it and didn’t want Chinese junk) was added to new $168 GE chest freezer from Home Depot.
Temperature is set at 30F, compressor comes on at 34F, and probe is in free air space apx. 4″ above lowest point. Settings below these points results in food beginning to freeze in lower areas.
Interior temperatures/operation verified with calibrated Cooper instrument.
Interior condensation forms as ice in one lower interior corner and its only been defrosted once since installation.
Exterior condensation forms on bottom of unit and feet/base should be added to raise unit off the floor to prevent accumulation/damage to floor.
Power cycles are nearly invisible on graph display of whole-house energy monitor so I didn’t investigate beyond checking that current draw was within manufacturer’s claims.
Common sense says to add fan to circulate internal air but temperature only varies a couple degrees from top to bottom.
Saves energy and food stays colder/lasts longer. Adds convenient/additional flat surface in kitchen.
Visitors: “Where’s your refrigerator?”
Thanks for a great idea. I’m in the US, getting ready to order TWO of these things (WIN 100 by Lux):
One will be for a freezer>fridge conversion as y’all describe.
The other will be to keep my homemade hot tub at a steady temperature. The WIN 100 plugs into an extension cord, you plug your appliance into the WIN 100 — I don’t want to deal with hooking up wires. The problem is that the temperature probe is about an inch from the unit, and the unit is for indoor use only, or needs to be carefully protected from moisture etc.
Rather than splice the probe wire to run outdoors, I’m thinking about bringing the tub to the unit, so to speak. The tub will be just outside a window. Maybe a pipe or tube to bring some waste heat from the tub in through the window to warm the sensor area.
(That would solve the temp range too. Some of the heat will be lost before it reaches the sensor, so when the sensor reads 90F and shuts the heater off, the water temperature will actually be, say, ~107F etc, depending on how much heat I allow to be lost.)
Any ideas what I could use to bring the heat in through the window? A pipe or tube for steam might get the sensor too moist. Maybe using conduction, for example through a copper rod with an insulating sheath?
Did anyone ever work out if you can butcher these things to run on 12v or 24v without the use of an inverter. Keen to put one in the back of my van conversion and the moterhome products have ridiculous prices!
Great thread. It should be a stand alone topic.
Sorry guys. this is a no go.
Freezer cooling systems and compressors are designed for a specific range of environmental factors.
The freezer needs to cool the food to freezing, but also COOL THE COMPRESSOR.
The freezer will be designed to operate so just enough cold refrigerant is returning to the compressor under warm external conditions. The freezer gas boils off at around -24C to -27C. So the refrigerant returning to the compressor temp can be around -15 to -18C depending on ambient heat and current heat load inside the unit. This compressor will need that cold refrigerant to cool the compressor motor. If you go turning the temp up to 1C to 4C via and external thermostat, while it will cool to that temp, it wont do it for long. You will be staving the compressor of nice cold returning refrigerant, and you will be over heating the compressor on every cycle.
You will shorten the life of your compressor SIGNIFICANTLY by doing this.
I have been in the industry for 14 years, as a trade qualified refrigeration mechanic.
You can do it, and you will blow the compressor motor, and if you return the unit under warranty, you are cheating the system, by making the unit run outside its design conditions.
This article is socially irresponsible.
Sorry to chime in Mr Wallace, I only just found this thread and read to the end to find your expertise. Now I’ve got a question for you as qualified refrigeration mechanic:
If what you say is correct (freezer-fridge conversions will blow the compressor motor) then please how is Steca Germany able to offer the choice outright whether you wish to run their unit as freezer or as fridge you may do either, and change your preference every day if you so wish. Steca dc fridges/freezers by the way are the world’s most energy efficient (as low as 40W), not Sundancer USA as they like to claim (70W the lowest). Steca has an A+++ rating. A 70W panel with moderate sun is enough they say.
Is the explanation maybe that they have designed the compressor in that very way (to allow switching the modus), while when we aim to convert a freezer it was not designed for that switch, right?
Don’t wish to wee on your fire but the compressor (motor) isn’t designed to run at fridge temperatures & so will shorten it’s life. Also where does the moisture generated inside go? It’ll end up causing evaporator (the coolant pipes inside) & internal surface corrosion, leading to premature appliance failure. Top marks for effort, but not recommended. I’m a refrigeration engineer BTW.
G’day Mr Dirty Boots, I’m in Australia and recently completed a chest freezer to fridge conversion – a used 140lt chest freezer in immaculate condition $80 conversion kit $40. There is a thermostat conversion available here which solves all the likely problems with such a conversion (we are on solar with 24v > 240v inverter) including the issue Phil brings up see link: http://www.ebay.com.au/itm/Refrigeration-Thermostat-Convert-Freezer-in-to-a-Fridge-Conversion-Kit-/150950614639?hash=item23255b966f:g:SNsAAOSwtJZXVkZW.
I’m a novice really but always looking for ways to cut power consumption as I implement my off-grid cabin near the opal fields of Lightning Ridge NSW. Been running it now for 40 days and power consumption is at 9.8Kw in total and found the conversion very simple to implement. Vendors main caveat being to not altering the thermostat range frequently. I’ve been running it in the range of 0 >7 Celsius with no issues of moisture or anything else, I’m very optimistic that it will do me well into the future.
It really burns my bacon on what renewable energy companies charge for a high efficiency refrigerator. A grand for 2 lousy cubic foot refrigerator! What a rip-off. I like this idea of just buying a cheap chest freezer (about $150 at Wal-Mart) and an inexpensive replacement thermostat (about $80 off Amazon). Maybe a few dozen dollars for some optional foam insulation. And constructing a high efficiency fridge that uses less then 0.2/kWh per day. This project is definitely worth considering
I was looking to do this because I have an annoying sensitivity to noises in my home. My current refrigerator/freezer runs for about 15 minutes twice an hour so it’s on about half the time and is really getting on my nerves. I’m hoping to cut down on run time more than saving electricity.
About how often does your converted unit run and for how long?