We have a dental office. In the beginning of the Covid19 pandemic, I read HEPA filters were the way to go for air purifiers. I subscribed to Consumer Reports & chose the Alen brand Purifier. The 45i, is the 9th Alen we’ve recently purchased to ‘clean’ the air throughout our office & home. We have the T500 Towers in our treatment rooms & got one . We (2) 75i in our hallways & at home. They are beautiful, efficient & quite. We absolutely made the right choice to invest in Alen.