Freezer to Fridge Conversion, Make a Super-Efficient Solar Powered RV Refrigerator

Collage of solar panel on RV roof, chest freezer in RV, and 5th wheel travel trailer camped at lake

Why a freezer to fridge conversion? When you’re RV camping miles from civilization, a good working refrigerator is a must. A refrigerator should keep your food cold enough that it doesn’t spoil, and ideally sip as little juice from the batteries as possible. And it would be nice if one could make fewer trips to town for propane, or better yet, not have to rely on propane at all for refrigeration.

Before shelling out over $1,000 for an RV refrigerator, that will burn through your propane supply while boondocking, consider transforming a freezer into a super efficient refrigerator.

Chest freezer with door open showing food inside and temperature probe for the external thermostat
My freezer to fridge conversion. Notice the temperature probe for the external thermostat on the upper right.

My freezer to refrigerator conversion is so efficient that it runs completely off solar energy, with a system consisting of two 100-watt solar panels, two 12-volt deep cycle batteries, a solar charge controller, and an inverter.

Here in the sunny southwest, this is all the refrigerator needs to run continuously. It’s totally off-grid and requires no messy generator.

The conversion is so simple, and the cost is so low, it’s something I recommend for anyone who wants to live off-grid or reduce their impact on the environment. All you need is a chest freezer and an external thermostat control.

Midea 3.5 Cubic Feet Chest Freezer, Model WHS-129C1
Midea 3.5 Cubic Feet Chest Freezer

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The Chest Freezer

This is the Midea 3.5 Cubic Feet Chest Freezer (model number WHS-129C1) that I chose to install in my RV, and it’s about $230 on Amazon. It’s Energy Star rated with a $23 estimated yearly energy cost (if you were to plug it into the grid and actually use it as a freezer). What I like about this freezer is that it’s lightweight, doesn’t take up much space, includes a removable basket, and is whisper-quiet.

Why a Freezer?

First off, you might be wondering why you would want to use a freezer instead of a refrigerator? Well, there are two good reasons:

  1. Freezers are designed with thick insulation, after all they are meant to keep food frozen for months. This alone makes them much more efficient at keeping the cold air in and reducing power consumption.
  2. Chest freezers have top opening doors. Cold air sinks right? When you open a refrigerator, with the door positioned on the side, most of that cold air just sinks out the large gap you’ve created near the bottom. Chest freezers don’t have that problem, and much of that cold air is retained at the bottom of the freezer when the door is opened.

The External Thermostat

In order for the freezer to fridge conversion to function as a refrigerator, so your food doesn’t end up freezing, you will need an external thermostat that is made for refrigerators and freezers, such as this one.

I chose the Jonson Controls A19AAT-2C Freezer Temperature Controller, and it’s around $90 on Amazon.

These external thermostats are designed to override on-board freezer and refrigerator thermostats, to provide temperature control outside of the range of the on-board thermostats. This model has an adjustable range from 20 to 80 degrees Fahrenheit.

Johnson Controls A19AAT Type Cooling Thermostat for Portable Applications, control unit
Jonson Controls A19AAT-2C Freezer Temperature Controller

How to Install

Simply place the temperature probe into the freezer, plug the thermostat into the outlet, and plug the freezer into the thermostat.

I used a little putty tape (aka butyl tape) to secure the temperature probe to the inside of the freezer. Be sure that the tip of the probe is not in contact with the freezer walls.

Digital or Analog?

One thing I like about this model is that it’s a mechanical thermostat, and does not draw power like a digital thermostat, making this freezer to fridge conversion even more efficient. This type operates with a gas filled probe on a 6-foot capillary tube. When the gas contracts or expands in the probe, it triggers a mechanical device inside the control which turns the power on or off.

What’s the Temp?

There is no probe temperature readout on the dial, so it’s a good idea to keep a thermometer inside the refrigerator to observe the actual temperature. That’s why I have an indoor & outdoor thermometer mounted on my wall, with the temperature probe placed inside the freezer. This photo shows my food is plenty cold (32.7 degrees F), and that I should turn up the thermostat slightly.

Temperature reading on thermometer shows 32.7 degrees
Indoor/outdoor thermometer shows temperature inside freezer-fridge conversion

Freezer to Fridge Disadvantages

I do have a few gripes about this freezer to refrigerator conversion:

  1. A top opening chest freezer means that if there’s something you need from the bottom, you have to remove many items to get to it.
  2. Since the freezer is now a refrigerator, you have to find room for another freezer if you want a freezer. This is what I plan to do in the future, and a freezer about half this size should be adequate for my needs.

Energy Saving Tips

2 solar panels mounted on 5th wheel travel trailer roof
Solar panels mounted on RV roof make this a solar powered refrigerator

Here are some energy saving tips to keep in mind when doing a freezer to refrigerator conversion:

  1. Go with the smallest freezer that will work for your family. A smaller model will consume less electricity.
  2. Compare energy consumption between models. Doing a search for Energy Star rated freezers will help narrow down your list to only those which are most efficient.
  3. Situate the freezer in the coolest area of the RV if possible. Keep away from heating ducts, portable heaters, and direct sunlight. I usually position the RV so that the curb side faces south, leaving the opposite side, where the fridge is located, facing north. This keeps the fridge away from the south facing wall, which receives intense sunshine during the day here in the southwest.
  4. Cool hot foods to room temperature before storing them in the freezer. This reduces power consumption and avoids the danger of spoiling other food in the freezer by raising the refrigerator temperature to unsafe levels.
  5. Organize food, by keeping items you use most often up top or in the removable basket, and foods you use less often, near the bottom. This will make it easier to find what you’re looking for and minimize the amount of time the door is left open.

Freezer to Fridge Conversion Video

Watch this video I created about my freezer to fridge conversion to see how it’s done…


Overall I’m very satisfied with this freezer to fridge conversion and believe it’s a great low-cost and reliable way to keep food cold when RV boondocking and living off-grid.

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