Four important factors before purchasing air purifier

Once you have determined the correct type of air purification system that works best for your particular allergies, you also need to consider the following factors before purchasing:
Coverage area: Helps you match an air purifier with room size
Noise level: Air purifiers have a large range of noise output depending on fan size and air flow rate
Cost and ease of filter change: Most air purifiers require annual (or sooner) filter changes
Efficiency rating: How well an air purifier filters the air, rating systems vary. Try to find a purifier that filters the type of particles you are allergic to.