October 15, 2026 | Knowledge Sharing
Coating selection directly affects corrosion resistance, formability and cost. Here is a practical guide for appliance manufacturers choosing between PE, SMP and HDP coating systems.
PE is the most widely used coating for indoor appliance panels. It offers good flexibility (T-bend ≥ 2T), excellent adhesion and a wide color range at the lowest cost. With a 15–20 μm top coat, PE is usually the best cost-performance choice for indoor refrigerator cabinets, washing machine shells and water heater jackets.
SMP adds silicone to the polyester resin, significantly improving weather resistance and gloss retention. It is a good choice for parts that see indirect outdoor exposure — such as air conditioner components in sheltered locations and semi-outdoor installations.
HDP provides superior corrosion and UV resistance, with a service life that can exceed 15 years in mild outdoor environments — ideal for water heater jackets installed outdoors and AC outdoor unit cabinets. Actual service life depends on the coating system, environment and installation orientation; ask our engineers for project-specific guidance.
| Environment | Recommended | Typical Top Coat |
|---|---|---|
| Indoor, standard humidity | PE | 15–20 μm |
| Indoor, high humidity (bathroom heaters etc.) | PE / SMP | 18–20 μm |
| Semi-outdoor / sheltered outdoor | SMP | 20 μm |
| Outdoor (water heaters, AC outdoor units) | HDP | 20–25 μm |
Not sure which fits your product? Send us the appliance type and installation environment — our engineers will recommend the right system.
