Pressurizing Your Home To Minimize Infiltraton of Outdoor Particulate

When people purchase a home their primary concern is size, number of bedrooms, baths and back yard size. Concerns about the HVAC system, the heating/cooling unit, are seldom brought into the decisoin, Yet, this unit and associated returns, supplies and duct work, can make your home a dream home or living nightmare. Today, in most areas of the country it is now required to have a blower door test to determine if your home is postitive or negative when the HVAC system is operational. If the test shows the house to be positive, meaning that air is being pushed against the interior of the house and keeps the home from any infilatraion from the outside. Obviously, the opposite occurs when the tests show the house to be negative. Under these conditions the house will actually suck in any fine particles through any passage way between the interior and exterior of the home. This means more dust and allergens as well as bringing in more moist hot air in the summer and cold dry air in the winter which make the HVAC system run longer and work harder and crate higher energy bills.

Sizing of the HVAC system should be done by professionals and higer Seer rated systems are must more efficient over the long haul. You may want to have a blower door test done on your home if it is 10 years or older. if the house is negative is it possible to make some modifications to the returns and supply runs to adjust for this issue. Using the correct size and rated filter for your home and system is also critical. The more efficient air filters may work better at removing airborne particulate but if they are too restrictive they can reduce the air flow through your HVAC unit and crate negative pressure in your home. In any case, keeping your home pressurized is the positive way to go.

For information on the Pure Air Systems line of HEPA and Carbon air filter systems pleae go to our website at:   or call us anytime on our toll-free number at: 800-869-8025.

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Pressurizing Your Home With PAS HEPA Filtration Systems

The majority of most homeowners are not aware that if their HVAC system is not properly balanced, when the heating/cooling fan system comes on the house may be pulling in outside air into their environment. This is referred to as the house being negative. Since your home is not really air tight, anytime the HVAC fan comes on the system will pull air through the returns and push the cooled or heated air our the supply ducts and registers and if there is more return than supply outside air will come in and make up that difference. 

This is a significant challenge as the air being pulled in from the outside will contain fine airborne particulate and some gaseous pollutants especially if you are near a road or high traffic area. This airborne dust is usually not captured in any of the air filters that are part of your HVAC system so this particulate matter will usually settle out on your floors, furniture and counter tops.

In 1985 Pure Air Systems was created and it was one of the first companies to offer true fan powered, certified HEPA air filtration systems for the residential market. The first model, 600HS was designed to attach to the return air side of the ducted heating/cooling system and filter a portion of the air in the house constantly when the fan was running. In most cases it can filter all the air in the house 24 to 48 times per day. 

One of the other advantages of this system was the inclusion of both a ring panel prefilter and true carbon media filter so removal of fine sub-micron particulate and gaseous pollutants was also accomplished. In addition, it is possible to introduce a small amount of outside air into the 600HS, or whichever PAS unit you are using, and this will fill filter any of the air coming into the house and help to maintain a more balance house pressure while still cleaning all the air in the house. And because this small amount of outside air is being introduced prior to the HVAC unit. all of it will be both filtered and heated or cooled.

For more information on the complete line of HEPA and Carbon based air filtration systems please go to our newly redesigned website at:  or call us on our toll-free number at:  800-869-8025.


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Using Positive Pressure With Air Filtration

The word pressure connotes a number of concepts. There is pressure to get things done on time, pressure cooking for vegetables and pressure to form a mold with an hydraulic machine. Pressure can be both negative and positive. The use of pressure as it relates to filtration is usually only associated with the medical or chip markets but has more recently been incorporated into the residential markets.

In the medical markets the use of HEPA filtered air for both general IAQ and for surgery suites and isolation rooms is standard. All hospital surgery rooms are pressurized using 100% HEPA filtered air so that if anyone enters the room during a procedure the air will push out through the door or opening not allowing any unfiltered or contaminated air to enter the room.

In the electronics, chip and optics manufacturing processes the same procedure is used. HEPA filtered air is pushed into the assembly and manufacturing rooms at high rates; often changing all the air in the room 100 times per hour. Again, the pressurization of the room eliminates any dust, dirt or airborne particulates from entering the sterile assembly environment even when the room is accessed from the outside.

Pure Air Systems has been manufacturing HEPA and Carbon based high end, commercial grade HEPA filtration systems since 1985. Their fan powered systems are designed to either attach to an existing HVAC system or they can be used as stand-alone units. Over the past 27 years of operation the customer base for PAS has moved away from Residential only to a 60/40 split between the commercial and residential markets. With commercial being the larger growth sector.

Pure Air Systems has numerous HEPA systems in the medical and electronics markets. Some or used for general air filtration but the majority are used for critical care or critical component processes. And almost all of these are used in positive pressure operations. The ability to incorporate the same positive pressure techniques used in the commercial markets into the residential and office markets has been an interesting project.

The introduction of outside, fresh filtered air into a residential or office structure is accomplished by adding one of the PAS HEPA based systems to the HVAC unit and introducing small amounts of outside air through the the HEPA/Carbon/Prefilter filtration package and slightly pressurize the living environment. This significantly reduces the entry of airborne allergens and pathogens into the living space and also reduces the levels of CO2 in the homes and offices.

The use of positive pressure for reduction of airborne contaminants is very effective and in most cases fairly inexpensive to accomplish. For more information on using the PAS HEPA systems to pressurize your home, office, clinic or surgery room please go to our website at: or follow us on Twitter @pureairsystems or like us on our Facebook page. Of course you can always call us on our Toll-Free number at: 800-869-8025.

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