Check the samples
Reputable, large-scale manufacturers have a history of numerous large-scale projects and samples, especially in cold northern regions and even Tibet. Companies with a proven track record of sample projects tend to have more stable products with superior technology and energy efficiency.
Check the weight
A standard piece of equipment should consist of a compressor, four-way valve, electrical control system, shell-and-tube heat exchanger, and finned heat exchanger. Some manufacturers use smaller compressors and heat exchangers to assemble equipment, but their direct heating power is far below the stated value. For example, a standard 13HP direct-heating unit (PASHW130SB-2-C) has a standard net weight of 310KG.
Check the service
This is the most important point. Reputable, professional manufacturers offer a 6.5-year full warranty, while smaller, less reputable manufacturers, due to product quality issues, only offer a 2-year warranty. There is a fundamental difference between a warranty and a full repair; please search online for the difference! Remember this.