When selecting a diffuser, prioritize the Atomization Technology. Cold-air diffusion (nebulizing technology) is superior as it breaks down essential oils into a dry mist without heat or water, preserving oil integrity. Ensure the Coverage Area (measured in square meters or cubic feet) aligns with your space. For large-scale HVAC integration, look for built-in fans and adjustable scent intensity levels (typically 10-20 levels). Additionally, verify the Noise Level is below 35dB for office or hotel environments to ensure a quiet atmosphere.