Our HVAC diffuser covers up to 3,000 sq ft. This diffuser can disperse your choice of fragrance may it be for your Home, and place of business. The HVAC diffuser has a set level of one through twenty-five. The higher the setting, the longer it will diffuse. The bottle capacity holds fragrance oil at 1 liter which lasts for about one month per refill depending on your HVAC diffuser set level. Combine this HVAC diffuser with any of our custom-made fragrances to capture the essence of a 5-star hotel.