3 Steps to Better Home Filtration The number one question we get at Air Purification of Houston is “What can I do to clean my whole house with a central system”? This automatically takes us to the a/c system which is the first step. Step 1. General Filtration A.    People often hear that they want or need HEPA filtration. HEPA filtration is the most efficient filtration in the world. However, it cannot be used by itself because of the tremendous restriction to the airflow on the system. Therefore, “Whole House HEPA” air cleaning systems come as a packaged unit with its own separate motor/blower that pulls the air (600 CFM typical) from the a/c duct through the HEPA filters and then back into the a/c duct. 600 CFM sounds like a lot but even a 3 ton a/c system moves 1200 CFM which means only half the air is being cleaned on a single pass. That coupled with the knowledge that an a/c system is only designed to run 15-20% of the time and you spend a lot of money for something that we feel is not very cost effective. Cost for this type of system typically runs $1,200-1,500. Filters get replaced once per year and you must crawl into the attic to change filters. The downside besides the extraordinary price is that only half the system is being cleaned because the duct from the return air grille back to the filter housing will continue to get dirty which will eventually need to be cleaned to eliminate any odors from building up. B.   An alternative to this is a media filtration system made by several major companies that will do a great job in terms of reducing the dust levels and helping to reduce any type of allergy and asthma problems. Because they are not HEPA they do not require their own motor/blower system because they don’t put excessive strain on the system. Filters are again changed out once per year. Again the down side is the cost ($500- 800) per system and the fact that half the system is getting dirty because the filter housings are required to be installed in the attic. C.   The Enviro Max® is a patented system that finally addresses all the above problems. First, it is installed in the standard return air grille which allows you to not only filter the air, but keep the entire system clean. The filter is 98% efficient at 5 microns. This may not mean much to the average person, but ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers) has determined that 99% of the dust floating in your home is 5 microns and smaller (invisible to the human eye). In addition, they found that dust 5 microns and smaller is what damages your lungs. Everything bigger is naturally filtered out by your body’s natural defense system. Now for the best part, we carry 15 standard sizes and can custom make any size. Systems require the housing (1 time charge of $30) and then the filter which is $65. This is less than the average person spending $7-8 on a pleated one inch filter once per month. Custom filters are $10 more for each the housing and the filter. Filters are changed once per year as in the above systems. Step 2. Ultra-Violet Light The main purpose of UV light is to kill mold and mildew that will grow on the a/c coils. The secondary benefit is killing viruses and bacteria. In order for UV light to work, it must be placed preferably on the down stream side of the coils. It is EXTREMELY important that the bulbs stretch all the way across the coils so both sides of the fins are in direct view of the UV bulb. This is imperative in order for the UV light to keep mold and mildew from growing on the coils. UV light does not kill by “reflection”. Putting a small bulb that stretches halfway across the coil fins and gives off a “blue light” does not constitute a properly sized system. A single bulb system can keep the coils clean but it will take a dual bulb system to adequately kill airborne viruses and bacteria. It takes an intense light to kill the viruses and enough dwell time for the viruses passing across the bulb. Because the typical a/c plenum does not allow for the dwell time the only way to effectively go after the viruses is to use a dual bulb system and get more UV output. It should be noted that viruses are so small they will pass through HEPA filters and this is why in “clean rooms” or surgery rooms a combination of HEPA and UV lights are used. Equipment for a single bulb system is approximately $400 plus installation (typically $75 unless electricity is required) and $750 for a dual bulb system. Step 3. Portable Units Portable HEPA filtration units are used in conjunction with the above mentioned systems. Portable units operate 24 hours per day 7 days per week. The HEPA filters typically get changed once per year. The advantage with these units is that when the HVAC system cycles off, these will continue to filter the air. During the fall and spring when allergies are typically at their peak, the weather is usually milder and the HVAC don’t run much. The disadvantage is that they will only clean the air in the room that they are located in. There is absolutely no unit that can clean the whole house with 1 unit. It is physically impossible and anybody making these types of claims is not being practical and just trying to get in your pocketbook. Quality units run from $400-600. Now that you understand the 3 different steps or possibilities and the associated costs, it is easy to see why we recommend starting off with the Enviro Max® once a year a/c filter.