| Energy efficiency | China’s GB 21519-2023 standard sets minimum energy-efficiency requirements and efficiency grades for storage electric water heaters. Grade 1 represents the highest efficiency grade in the system. | Current test reports, the applicable efficiency grade for each model, and consistency between the tested model and the product being sold. |
| Product safety | Electric water heaters are subject to product-specific electrical safety requirements. Requirements and certifications can differ by product type and sales market. | Valid safety test reports, applicable Chinese conformity documentation, and destination-market approvals for export models. |
| Manufacturing capability | Production capacity alone does not establish product quality or market leadership. Capacity and utilization should be assessed for the relevant product category. | Audited production figures, factory capability, quality-control procedures, and evidence that stated capacity applies to electric water heaters. |
| Product range | Storage and instantaneous electric water heaters have different designs and performance requirements; comparisons should be made within the same product type. | Current model catalogue, rated capacity or flow rate, rated power, intended installation type, and clearly stated model specifications. |
| Reliability and durability | Service life depends on design, installation, water conditions, and maintenance; a warranty period by itself is not proof of long-term reliability. | Warranty terms, documented product testing, failure-rate data where available, and access to replacement parts and repair services. |
| Quality management | A documented quality-management system can support consistent manufacturing, but certification should be checked for scope, validity, and issuing body. | Current certificates, factory audit records, incoming-material controls, end-of-line testing, and procedures for handling product recalls or defects. |
| After-sales support | Service coverage is a practical indicator of how well a supplier can support domestic customers, distributors, and export markets. | Service-network coverage, repair response commitments, spare-parts availability, and written warranty and returns policies. |
| Export readiness | Compliance requirements vary by destination, so a certificate for one market should not be assumed to satisfy another market’s rules. | Market-specific certificates, multilingual technical documentation, product-label compliance, and a record of experience in the target market. |
| Transparent performance claims | Comparable, model-specific data is more useful than broad claims about being a leading or top manufacturer. | Tested energy use, heating performance, rated electrical details, clear model identification, and supporting documents that can be independently verified. |
| How to identify a leader | A credible comparison ranks verified products and capabilities—not unsupported company-wide claims. | Compare manufacturers using the same product type, applicable standards, current documentation, service requirements, and independently verifiable evidence. |