Hot air rises, cool air sinks…it’s thermodynamics 101, so why are modern fridges vertical? Totally beats me, because as soon as you open the door, a load of the air you just paid to cool spills out all over the floor. If there is a leaky seal, same thing. If I were on the Dragon’s Den panel and someone pitched that to me as a new concept, I would be loath to invest a dollar. It goes against the laws of nature and therefore can never be truly efficient. Nevertheless, it is the industry standard, so I guess a lot of people feel it is well worth wasting energy for the sake of convenience and a compact design.
The average home in Australia uses about 18 kWh (Kilo-watt hours) of power a day, of that between 1 and 2 are expended on the fridge. For people with a fridge over ten years old, probably even more. I rely on a solar system that produces 6.5 kWh a day, so there is no way I can condone one appliance sucking up all that juice. A comprehensive search online made it very clear I was never going to find a fridge that was seriously energy-efficient straight out of the box, but I did discover a lot of interesting posts by people who had successfully converted chest freezers into exactly the type of fridge I was looking for.
Chest freezers are horizontal and open upwards, so when you lift the lid, most of the cold air stays inside. They also tend to be better insulated than fridges, which further increases efficiency. The only downsides I found to this approach were that in many cases the modifications required were either expensive or involved messing with wires. Whilst I will try my hand at most things, I am pretty averse to getting fried so after a couple of hair raising incidents, I have made it a personal policy never to interfere with anything electrical. Thankfully, ebay offered the perfect solution, a simple, plug in, external thermostat so cheap that at $19.99 I could even afford a spare! ( you can find it here for AUS$17.99 and here for £12.59, it is available internationally).
I bought two 244 litre capacity A++ super energy-efficient Vestfrost SE255 freezers, which run on only 0.47 kWh of power a day. One I use as a stand alone freezer to preserve our garden produce, the other I fitted with the thermostat. The thermostat allows the freezer to reach the temperature I specify (3 degrees), and then switches it off. The cold air is trapped inside thanks to the awesome freezer-level insulation, and then when it finally starts to warm up, the thermostat switches the power back on. The fact that the freezer is not running most of the time means that although it maintains the correct temperature, it uses only 0.1kwh a day, which is between 10 and 20 times more efficient than a conventional fridge. If I was on the grid, my fridge would cost only $10.73 a year to run, compared to $214.64 if I were running a 2 kWh a day appliance.
The thermostat is simple to set up. After you feed the sensor inside the fridge (follow the wiring of the fridges own sensor, see pic right), it’s pretty much ‘plug and play’…as long as you have read the instructions in English. Mine arrived with a Chinese manual and although I thought operating it would be fairly intuitive, turns out it wasn’t, at all. For two days we were running the thermostat as a heater rather than a cooler, an additional function I didn’t even know existed. Unfortunately, having the thermostat on this setting meant that it ran continually in an attempt to ‘heat’ the fridge to 3 degrees. Obviously the more it ran the fridge, the cooler the internal temperature became and so in a bid to heat things up, it ran some more. To avoid this Catch 22 situation and ensure it is operating in cooling mode, simply press the ‘SET’ button to go into ‘WORKING’ mode, then press the down arrow for four seconds to switch to cooling mode. If all is correct you should see a green light (red indicates heating mode and results in a -18 degree fridge). The final thing we did was to slip the entire thermostat inside the side panel of the fridge to keep it neatly tucked out of the way.
To achieve maximum efficiency, follow the same general rules you would for any fridge:
– Ensure the temperature is set to between 3 and 5 degrees. Any warmer and you will waste food, any cooler and you are wasting energy.
– Always allow food to cool before placing it in the fridge to avoid raising the internal temperature.
– Locate your fridge (and freezer) as far away from direct sunlight and heating appliances (e.g. cookers, microwaves, radiators etc.) as possible.
– Leave a gap of about 100mm between the fridge and the wall. Restricting airflow around the coils reduces heat dispersion and significantly reduces efficiency.
– Brush the coils twice a year as an overload of dust will also reduce efficiency.
– Try to avoid constantly opening the door or leaving it open for extended periods whilst contemplating meal options. Although a chest freezer will retain a lot more of the cold air than a vertical fridge, some will still spill over, and the upper layer of cold air will gradually absorb the warm air above.
– Empty, defrost, switch off and leave the door of the fridge ajar if you are going away on holiday.
So far our fridge is running perfectly, I will update this post if the situation changes. I love the fact that it is silent most of the time and that it provides more than enough space for all of my needs. There are however, some disadvantages, which mean this may not be the ideal solution for everyone:
Space – A chest freezer takes up considerably more floor space than a vertical fridge and so may not fit in your kitchen. This set up also does not incorporate a freezer, so that needs to be factored in separately.
Depth – You need to lean into the freezer to remove things from the bottom. This could prove difficult for elderly people. On the plus side, it may also be an effective deterrent to children raiding the fridge!
Organisation – Unlike a vertical fridge with it’s multiple shelves, the chest fridge has less compartments and so it can be more difficult to find things. I alleviated this problem by adding an extra basket in the top, and adding plastic stackable storage containers below. Condensation collects in the bottom of the fridge over time and this also keeps the food from getting wet.
Cleaning – The depth and the fact that the chest freezer opens upwards makes it a bit more difficult to clean.
If you are considering switching to a new fridge, why not invest in a kilo-watt meter (available from amazon or ebay) and work out how much power your current fridge is consuming. Whilst going as far as converting a chest freezer may not appeal, if you have an old fridge you could find that you are able to save more on your energy bill than the initial purchase price simply by investing in a new more efficient model.