Direct cool refrigerators are also known as conventional ‘frosty’ refrigerators. Moisture condenses continuously on the cold coils (evaporator) to form frost inside this type of refrigerators. As for frost-free refrigerators, a special built-in heating element melts the accumulating frost regularly. As such, users do not need to defrost manually.
Although frost-free refrigerators can defrost automatically and are more convenient, they also have certain limitations. Users should consider the following aspects to assess whether frost-free refrigerators are suitable for their homes.
Frost-free refrigerators are generally larger in size with 2 or more doors. They may not be suitable for smaller living space.
Level of moisture vaporization of food items
When moisture of the food items stored inside the refrigerator vaporizes, it will add to frosting. Using a frost-free refrigerator is therefore more convenient in such situation! On the other hand, if the items you store do not vaporize a lot, e.g., Tetra Pack beverages, then the speed of frost formation will be lower and the chance of severe frost accumulation will also be smaller.
Frost-free refrigerators are generally more expensive. In addition, as the defrosting function consumes more energy, the electricity costs of running frost-free refrigerators are generally higher.
Inverter refrigerators are becoming more available nowadays, and they are generally more energy efficient. However, this technology is mainly used in refrigerators of larger size. For example, in the test conducted, 5 invertor refrigerators were all of larger size and frost-free models. And the smaller size direct cool refrigerators were all of fixed-speed compressor type.
Apart from size, energy efficiency and price, consumers may also consider the following aspects when making comparisons across different refrigerator models:
Freezing and cooling capacities
If you want to chill or freeze your food and drinks quickly, you will need to choose a refrigerator with good freezing and cooling capacities. Taking the cooling capacity as an example, the time taken for some test samples to drop from room temperature to 10°C could range from 2.9 hours to 6.7 hours. In addition, some models may have a ‘fast freeze’ function, giving it a superior freezing capacity.
Coldness preservation efficacy
In the event of a power outage or temporary suspension, the coldness preservation efficacy of a refrigerator becomes very important. In the test conducted, the time taken for the freezer compartment to rise from -18 °C to -9°C ranged from 3 to 12.5 hours.
It refers to the rate at which the inside temperature of a refrigerator drops to a standard level when the unit is put in an extremely hot environment. In the test conducted, one model failed to bring the average temperature of the fresh food compartment down to 8°C after 23 hours, causing the test to halt.
Normally, people just randomly put their food items inside the refrigerator wherever they see space. In fact, temperature varies in different areas of the refrigerator. As food items may have different storage requirements, it is best to store them according to the following recommendations, e.g., fresh meat should be stored in a cooler section such as next to the fan holes; eggs should not be stored in the freezer, etc.
Have you got all the necessary tools to do your defrosting job, e.g., screwdrivers and a hair dryer? Hold on! Read the following tips first:
Turn the power off
Unplug the unit from the power source and remove food items that need to be stored at lower temperatures. Open the refrigerator doors to make defrosting faster.
Don’t rely on sharp objects / hairdryers
Scraping ice inside the refrigerator with sharp objects may damage the refrigerant ducts. At the same time, attempts to melt ice with hairdryers can be counter-productive as they may deform the plastic parts inside the refrigerator.
Prepare towels / old newspapers
Towels and old newspapers can be very handy to soak up the excess water that overflows from the bottom tray during defrosting.
Although the living space in Hong Kong is generally small and the kitchen space is also limited, you should still pay attention to the placement of the refrigerator, and should not choose a site too close to the stove. Take the models tested by the Consumer Council as an example, they all used R600a (isobutane) as the refrigerant and insulation materials containing cyclopentane, which were all inflammable substances. Lighting a flame near them would greatly increase fire risks!
For more information, please refer to the article ‘Mid and Small-Size Refrigerators with High Energy Efficiency. Pros and Cons of Frost-Free and Direct Cool Models´ (Chinese version only) in issue #538 of CHOICE Magazine.
Further reading: Some energy-saving tips on refrigerators
After selecting a good refrigerator, you need to know how to use it properly, so that you can effectively save energy (and greatly reduce your electricity bills)! You may watch the video ‘The Energy-Saving Tips on Refrigerators´ (Chinese version only) and start applying those tips!
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