1   The manufacturing and production of environmental test equipment have been continuously developing for several decades, and its basic technologies (such as refrigeration, dehumidification, and heating) have matured. With the advancement and development of industrial technology, many new application technologies have been continuously introduced into environmental test equipment, such as computer technology and fuzzy control theory. The working principles, applied technologies, and even structures and materials of the equipment produced by various manufacturers based on decades of manufacturing experience. They all have many similarities. However, due to the production mode of environmental test equipment characterized by "multiple non-standard, multiple varieties, and small batches", the reliability of the products has always been a problem that troubles both domestic and foreign manufacturers. The key lies in that manufacturers must manage meticulously, have complete processes, adopt comprehensive testing methods, and be conscientious and responsible for quality. Meanwhile, environmental test equipment is a durable good. Some problems and design flaws will only be exposed after years of use, and the problems can only be identified through statistical analysis. A mature and highly reliable product often requires years of improvement and refinement. Therefore, for environmental test equipment manufacturers, having a certain production scale and production history is one of the necessary conditions for the products to have high reliability.

2   Quality control in the production process. The quality control in the domestic production process has been greatly improved. The quality control of the production process is related to the management level and production mode of the manufacturer. Passing the ISO certification is a sign that the quality control of the production process has become standardized. In addition, domestic and foreign manufacturers of temperature and humidity environmental test equipment have accumulated rich experience in the production of climate environmental tests. As for how to choose a manufacturer, there are still some factors worth paying attention to and considering.

（1）Cost performance

On the basis of thorough verification of the technical parameters and reliability of environmental test equipment, cost performance is an important factor that should be considered. The import of environmental test equipment is without exception sold domestically through agents. The price factor not only depends on the cost and profit of the manufacturer, but also includes many intermediate link costs and sales commissions. Under the same manufacturing cost, reducing intermediate costs is an important factor in lowering the order price. For products with relevant technical indicators in the same country, the manufacturing costs are roughly the same. Even if there are differences among products produced in different countries, they will not be too significant.

(2) The extent and ability to meet users' needs.

When users order equipment, they mainly choose based on the requirements of the test workpieces they need to conduct. Many of these requirements are non-standard. Whether the manufacturer can meet their test requirements and to what extent they can do so also reflect the manufacturer's capabilities and will be an important factor that users care about.

(3) After-sales service and the ability to handle equipment malfunctions.

During the long-term use of equipment, some malfunctions are inevitable. Once problems occur, can users enjoy timely maintenance services, or can they quickly determine the fault handling methods based on the equipment's own fault diagnosis capabilities, so that the equipment can restore its performance as soon as possible and be put back into use? In this regard, both domestic and foreign manufacturers have already made or are making active efforts, such as establishing rapid response maintenance teams and adding diagnostic and fault early warning system software to computer control systems. Users can handle faults as soon as possible based on the information provided by the computer.