The Coway AP-1512HH and PuroAir 400 both aim to deliver cleaner air, but they do so with key distinctions that impact real-world performance and value. The most glaring difference lies in their smoke purification capabilities and transparency. The Coway Mighty proudly lists a CADR Smoke rating of 240, a concrete metric demonstrating its effectiveness against smoke particles. In contrast, the PuroAir 400 lists a CADR Smoke of 0.0, despite claiming to filter smoke, which raises questions about its performance in such crucial scenarios. This makes the Coway a far more reliable choice for environments where smoke (from cooking, wildfires, or other sources) is a concern. Regarding coverage, the PuroAir 400 technically offers slightly more effective coverage at 416.67 sq ft compared to Coway's 375 sq ft. However, PuroAir's marketing claim of 'Covers 2,000 Sq Ft' is highly misleading and significantly inflated relative to its actual AHAM-verified coverage. Coway's more modest 375 sq ft claim is consistent and achievable. Both units feature smart sensors to auto-adjust fan speed based on air quality, enhancing user convenience. Coway further distinguishes itself with an Eco Mode that conserves energy by pausing the fan when air quality is good, a feature not explicitly mentioned for the PuroAir. While PuroAir highlights quiet operation and a dedicated sleep mode, Coway is also well-regarded for its relatively low noise output. From a filtration perspective, Coway specifies 'True HEPA' and removal of 99.999% of 0.3-micron particles, including 99% of VOCs and odors. PuroAir uses a '3-layer filtration system' including HEPA, claiming 99.9% removal of pollutants. While both are effective, Coway's slightly higher percentage and specific mention of 'True HEPA' suggest a marginally superior filtration standard.