Am am investigating the follow Whole House HEPA Filtration System. When installed is does not restrict the air flow across the heating or coiling fins/coils. This is called a bypass filter. There are filters that need to be changed on a regular bases. The equipment cost is about 400.00 and installed depends of if U have and electrical outlet available and than hang it, and connect the ductwork. This "maybe" a DIY project for somepeople, others get a A/C to install it. Its about a 1-2 job. The product that I am looking intois a FanTech three different models. DM3000, CM3000, and CM3000 Note this is a certifided HEPA System Not all filtration filters or system all HEPA even when the manufacture tells U they are. Be careful in that respect.

Tiger is correct that those filters can certainly be used if everything is sized properly... that being said are you having air cooling issues? You'd stated you got an efficiency check done... so strictly financial concerns or is something amiss with the temperatures in your home? All I'll say is that using cheaper filters can be better idea if you're having air flow issues and for the most part they'll still catch pet hair, dust, and dander. The tradeoff is the dust that does slowly make it into your system and is eventually recirculated.

To answer your MERV question- MERV is an industry standard rating, so it can be used to compare filters made by different companies. Most filters are labeled with a MERV (Minimum Efficiency Reporting Value) rating number, which measures a filter's ability to trap particles ranging in size from 3.0 microns to 10.0 microns. Â A MERV rating of 6 means the filter is 35% to 50% minimum efficient at capturing particles, sized 3.0-10.0 microns. Â A MERV rating of 7 means the filter is 50% to 70% minimum efficient at capturing particles, sized 3.0-10.0 microns. Â A MERV rating of 8 means the filter is 70% minimum efficient at capturing particles, sized 3.0-10.0 microns. Â A MERV rating of 11 means the filter is 85% minimum efficient at capturing particles, sized 3.0-10.0 microns. MERV ratings go right up to 15+, not seen on residential systems though as these are enhanced HEPA, that won't work on standard blower systems.

@opaone, In an earlier post, you quoted your "buddy" at ASHRAE who provided this position on behalf of ASHRAE: "Negative health effects arise from exposure to ozone and its reaction products. Consequently, devices that use the reactivity of ozone for cleaning the air (emphasis added) should not be used in occupied spaces." I don't know if ASHRAE states that as their position, but I would fully support it. There are cleaning and disinfecting devices which intentionally produce ozone as a disinfecting agent. These devices are advertised to remove chemical contaminants, odors, kill mold spores, etc. which, if they do it at all, is by chemical reaction with ozone. They aren't advertised as particulate filters. By contrast, electronic air cleaners, such as Honeywell's F300, are electrostatic precipitators. They remove particles from air by electrically charging the particles which are then collected on a collector plate which has the opposite electrical charge. Although not intentional, electrical arcing can sometimes occur in electrostatic precipitators and ozone can be produced as a consequence. To be abundantly clear, electrostatic precipitators don't use the reactivity of ozone for cleaning the air . Ozone is naturally occurring in outdoor air. Indoors it can be produced at trace levels by motors, hair dryers, laser printers, and photocopiers to name a few sources. If you want to eliminate ozone from your home, you'll need to start by getting rid of all of those. Then you'll need to add a device to filter out naturally occurring ozone that enters via infiltration. I realize that houzz.com threads are dominated by homeowners and DIYers. If you want to argue a technical point with an experienced and credentialed professional, please bring some data, a link to a research report or something other than your opinion, a quote from an unnamed source or a general reference to your "extensive research." If you'd like to invite Allison Bailes to weigh in on this, please invite him. I'm getting tired.