As temperatures climb, air conditioners have entered their peak sales and installation season. Finance Investigation received reports from consumers saying that second-hand air conditioners bought on the market are noisy, consume a lot of energy, cool poorly, and give off a pungent odor when used. Yet the labels and energy-efficiency ratings all look like they came from legitimate manufacturers. What exactly is going on here?

　　Labels costing a few cents a set, applied at will

　　Decades-old air conditioners sprayed with chemicals passed off as new machines

Some time ago, consumer Xiao Xia selected two dual-purpose (cooling and heating) air conditioners on Xianyu, a second-hand idle-items online trading platform. Judging from the photos, the machines looked relatively new, and the seller said they had only been used for just over two years.

However, when the delivery technician arrived, Xiao Xia found that the air conditioner looked more worn than in the merchant's earlier photos. Xiao Xia began to have second thoughts, but the installation technician promised the machine would work fine and even came with a one-year warranty.

What Xiao Xia did not expect was that on the very night, just a few minutes after the air conditioner was turned on, the air purifier in the room maxed out its readings.

Consumer Xiao Xia: It maxed out within two or three minutes of turning it on; the whole room smelled strongly of renovation dust. It was completely unusable. Then I contacted the seller, who said he would send a technician. I waited half a month and no one came, and then I simply couldn't reach him anymore.

Beyond the air-quality problem, Xiao Xia also found that the second-hand air conditioner bought was noisy and cooled poorly, and when the electricity bill arrived at the end of the month, the cost was shocking.

Why do second-hand air conditioners bought online have these problems? What unknown tricks are hidden in such second-hand air conditioners? Following the leads reported by Xiao Xia, the reporter launched an in-depth investigation into second-hand household air conditioners on the market.

The Huayuan Road second-hand goods market in Nanjing was once the largest second-hand home-appliance trading market in Nanjing. Here, second-hand household wall-mounted air conditioners mostly cost just over 1,000 yuan. Compared with the 2,000–3,000 yuan or 3,000–4,000 yuan price tags of new air conditioners on the market, the price advantage is obvious.

Not only that, some merchants also pitched to the reporter a cheaper type of second-hand air conditioner—one that had been "bleached."

The merchant told the reporter that so-called "bleaching" means cleaning old air conditioners with various chemical cleaning agents to whiten yellowed old machines until they look like new ones.

In fact, even after the casing is bleached, the nature of the material cannot be changed. Depending on the number of bleaching treatments, the casing will generally turn yellow again after three to six months. Therefore, to isolate these bleached machines from air and ultraviolet light, merchants choose to wrap the casing in plastic cling film before selling them.

As the investigation deepened, the reporter also came into contact with wholesalers upstream of the retailers, who ship in larger volumes. They revealed to the reporter that these "bleached" air conditioners on the market have in fact all been used for more than ten years, and some are old machines that have been used for nearly twenty years.

The reporter also learned that air conditioners produced ten or even twenty years ago mostly used polypropylene material for their casings. During long-term use, this plastic material gradually turns yellow due to factors such as ultraviolet radiation, high temperatures, and oxidation. Whitening yellowed old machines through cleaning is what merchants call "refurbished machines."

And to make these "refurbished machines" look newer and sell better, labels must be applied—that is, the energy-efficiency label for the indoor unit, the power rating label for the outdoor unit, the production date, and other product-information labels.

Labels that are only applied after strict quality inspection when home appliances first leave the factory are here being applied at will.

So where do these markings and labels come from? Following the leads provided by the merchants, the reporter opened an online shopping platform and searched for "air conditioner labels." Besides the typical two-piece sets for indoor and outdoor units, there were also five-piece and six-piece sets including brand logos, separate production dates, and unit codes.

Some online merchants also noted in their purchase tips that these labels are suitable for use on second-hand air conditioners, with the energy-efficiency rating defaulting to Grade 1 and including a QR code. Information such as dates and energy-efficiency grades can all be customized.

On online shopping platforms, there are dedicated sellers for indoor-unit model labels and outdoor-unit labels, with a set of labels costing only a few jiao. Serial numbers, date strips, QR codes—virtually every air-conditioner-related information label is available.

It is precisely because of this full set of information labels that merchants appear so confident when selling, while it becomes even harder for consumers to discern the true condition of the air conditioners. And "refurbished machines" often do not last long.

According to this second-hand air conditioner wholesaler, it is no trouble at all for customers to want low prices, good appearance, or even a specified brand—they can meet all the requirements of downstream retailers. One "Meige" brand air conditioner, because its casing resembles that of a "Midea" air conditioner, can be transformed into a "Midea" air conditioner after a makeover and sold brazenly; this is also the model they are most willing to "refurbish" and counterfeit.

Abuse of cleaning agents and yellow-removal agents

The second-hand recycling market urgently needs rectification

Along both sides of Ningwu Highway in Yuhuatai District, Nanjing, are distributed more than a hundred shops of various sizes engaged in the recycling and reuse of second-hand home appliances, and more than half of them specialize in "refurbishing" second-hand air conditioners.

To remove yellowing from old second-hand air conditioners, a yellow-removal agent is mainly used.

After spraying the yellow-removal agent on the surface of the machine, it needs to be covered with plastic cling film and then exposed to direct sunlight. It turns white in a single day.

According to data, common yellow-removal agents on the market usually contain multiple compounds such as light stabilizers, penetrants, oxidants, dispersants, thickeners, and reducing agents. These ingredients can absorb ultraviolet light and prevent photodegradation, thereby keeping plastic products transparent and white. In addition, some yellow-removal products contain surfactants, organic acids, sodium hydroxide, and the like, which can dissolve stubborn yellow stains.

Industry insiders revealed that one of the most effective yellow-removal agents contains large amounts of titanium dioxide. On the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization, titanium dioxide is classified as a Group 2B carcinogen.

A merchant told the reporter that the reason these machines turn yellow is not only the passage of time but also the materials. On the market, different manufacturers use different plastic materials, and the time it takes to yellow varies; some machines turn yellow in less than ten years.

Besides yellow-removal agents, there is another cleaning agent used to deal with stubborn stains—Dichen—which is highly irritating.

The reporter learned that Dichen cleaning agent has an extremely strong dissolving and cleaning effect on dust and oil stains, but it is irritating to the skin and mucous membranes and has an anesthetic effect on the central nervous system. In severe cases, symptoms such as restlessness, convulsions, and coma may occur.

In addition, long-term exposure to Dichen cleaning agent may lead to chronic poisoning, causing problems such as neurasthenic syndrome, liver enlargement, and abnormal menstruation in women.

Zhang Ziqi of the China Household Electrical Appliances Research Institute told the reporter that second-hand air conditioners that have exceeded their service life pose many hidden dangers. Although they look clean on the surface after cleaning and "refurbishing," most of these merchants engaged in recycling and "refurbishing" second-hand air conditioners do not specially disassemble and clean the air ducts, fan wheels, and evaporators inside the air conditioners. Yet these places are precisely the breeding grounds for pathogenic bacteria such as Legionella and mold. And during the "refurbishing" process, the abuse of various cleaning agents and yellow-removal agents will also bring secondary pollution during use of the air conditioners.

Zhang Ziqi, Deputy Director of the Refrigeration and Air Conditioning Division of the China Household Electrical Appliances Research Institute: If we smell these odors in such an environment over the long term, the damage to the respiratory tract will be very serious, and harmful substances will irritate the central nervous system. Moreover, air conditioners that have exceeded their service life may have their energy efficiency reduced by 50%.

China is the world's largest producer and consumer of refrigeration equipment. We call on the relevant market supervision and management authorities to act swiftly and severely to crack down on the various irregularities in the second-hand air conditioner market, so that consumers can have more peace of mind and protection when buying second-hand air conditioners; and the relevant government departments, industry associations, and home appliance enterprises should also take practical action to promptly fill the standards gap in the field of air conditioner recycling and reuse, so that discarded second-hand air conditioners can truly be recycled and "turned from waste into treasure."