Several issues need to be addressed before you can purchase a whole house high efficiency particulate air (HEPA) filter system. You will need to know the size of your home, whether you want a central air purifier that is tied into the duct work or one that stands alone and whether you need any special filtration media in order to remove allergens. To be a true whole house HEPA filter, the filtration media must be able to catch at least 99.7 percent of airborne material that is 0.3 microns or larger. At these sizes, virtually all mold spores, dust mites and most viruses are filtered out of the air.
The first step to understanding the type of whole house HEPA filter you need is to measure your house size. You should determine the size of the structure in square feet or meters and cubic feet or meters. After you have this information, you can begin looking for the system that will fit your needs.
For whole house HEPA units, you have two choices. Units are available that tie directly into your existing ductwork and work off the central heating, venting and air conditioning (HVAC) system. The second option is to purchase a standalone model that does not require connection into the HVAC system. Standalone models are less expensive to install, but their filter performance might be less than what you get from a central air purifier system that is actually tied into your ductwork.
Another thing to consider when choosing a whole house HEPA filter is whether you need it to remove allergens smaller than 0.3 microns. Most whole house HEPA systems are available with a variety of options for filter sizes. It is best to check on this before you order a unit. It will be important to know whether the unit you purchase offers HEPA filters in the size that you need, because not all of them do.
In order to save money in the long run, make sure to find out how often the filtration media has to be changed under normal operating conditions. Higher-quality whole house HEPA systems typically need to have the filtration media changed less often. These systems might cost more to purchase, but they often last much longer and can save money in the end.