The best room for a unit is the one where you spend most of your time -- usually your bedroom. You can find HEPA filters in most home improvement stores or online .
Some vacuum cleaners have HEPA filters that trap more dust from their exhaust. HEPA-equipped vacuums throw less dirt and fewer microscopic dust mites back into the room as you vacuum. Some people say improve after using these vacuums.
Is in-service efficiency testing also required or recommended?
Periodic testing (every 6 to 12 months) and testing whenever the HEPA filter is replaced are essential to ensuring that a HEPA filtration device continues to provide true HEPA efficiency. CDC Guidelines recommend such periodic testing and it is commonly required by facilities as well. It should also be noted that HEPA filters can begin to break down over time. Replacement every two years is highly recommended, even if the device is not used.