John,
I thought I would write to tell you how pleased I am with the heppa air filter system installed recently by Nittany Oil. First, I sure appreciated the installation skills of the men who did the work; the installation looks very compact and well-fitted. Second, the effectiveness in cleaning the air in my house is unquestionable: I no longer wake up sneezing and with a clogged head. When I stay overnight elsewhere, I notice a return of symptoms related to dust mite allergies. My allergist said that a heppa filter system seems to be the only one to rely on. Likewise, Consumers Reports had a review of various systems, and the only one that was effective was the heppa filter. There are stand-alone heppa filter machines, but typically one is needed for each room, and they add noise. I certainly do not mind spending money for something that really works and, in the long run, is actually less expensive than alternatives.
Best Regards,
Jack Neisworth
(Professor at Penn State University)