Be VERY VERY careful dealing with this company. You can use their website to read reviews about air purifiers but I do not recommend doing business with them. I ordered over $2000.00 in new purifiers. What I received were open boxed, scratched used air purifiers. Two of them had imbalanced fans so wobbled and rattled when turned on high. They are fast to take your money but go silent when you have a return. It takes days for them to respond to e-mails. After a ridiculously archaic method of processing returns, I finally shipped them back. The icing on the cake is when they charged me a $400.00 restocking fee so they could take these used units and sell them to some other sucker. Use this site to read reviews but go somewhere else to order them. This place sucks.