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Dr J Sublett, Leading Allergist

Room Air Cleaning vs. Whole House Systems

Filtration vs. Air Cleaning

Several major consumer publications and organizations offer consumers advice on the purchase of individual room air cleaners compared with whole-house systems. Basically, room air cleaners claim to clean one room and are portable devices which may or may not have the ability to move air. Whole-house systems are devices installed within a forced-air heating and/or cooling system, inside the existing ductwork. These systems range from a simple High Efficiency Particulate Air (HEPA) filter easily installed by the homeowner to contractor-installed germicidal and toxic gas light systems and humidification and/or dehumidification devices.

The recent popularity of individual room cleaners has been brought to the attention of several consumer advocate groups. One highly-advertised unit claims to be highly efficient at removing particulates from a room, and claims that customers are 100% satisfied with its quiet operation. A major consumer testing organization analyzed these claims and determined that, yes, customers were satisfied with the noise level because the unit had no fan or moving parts. However, when tested for efficiency (particulates, smoke, pet dander), the unit did not perform according to advertised claims. In a particularly twisted marketing campaign, this company has touted the weakest part of their product (the fact that it does not move air with a fan) as the most satisfactory aspect of their product.

Good Housekeeping goes even further and in their words: "Bottom line... save your money. You can't rely on this product to clean the air in your home. Plus, any retail room air cleaner has limited efficiency and effectiveness as they are only designed to clean one room at a time."

There are a variety of furnace filters available with a wide range of prices and reported efficiencies. Many of these filters are supplied by the furnace manufacturer upon installation or are available at retail outlets. Called "MERV Ratings" (Minimum Efficiency Reporting Value), the higher the MERV number, the better the efficiency. These filters are designed to protect the furnace and do a fair to poor job at that and are mostly made of fiberglass or a pleated blend of woven material. When choosing a filter, it is important to take into consideration its efficiency rating, as well as how restrictive it is to air flow. Generally the more expensive the filter is, the more restrictive it is to air flow due to it being more dense for higher efficiency. Filters that restrict air flow, more than the design of your heating and cooling system can handle, will affect the furnace's and air conditioner's performance and efficiency and may cause damage to the system.

Nature's Home products are designed to work in conjunction with your existing heating and air conditioning system. The high efficiency filters can be replaced easily by the homeowner. The whole-house systems are installed by professional heating and air conditioning contractors to convert your heating and cooling system into your whole-house air treatment center. The air in your home passes through this system several times an hour, unlike passive room cleaners. In order to effectively remove particulates, pollen, dander and smoke from the air, multiple passes through HEPA filters is required.

Stand-alone room air cleaners cannot possibly match the effectiveness and efficiency of whole-house systems. They simply do not move the large volume of air required to remove indoor air pollution. By using your existing forced-air system, you can have measurably cleaner indoor air.

Filter Choices

Nature's Home Products

Nature’s Home filtration products and air cleaners are designed by Heating and Air Conditioning Engineers and Asthma & Allergy Specialists. Nature’s Home products are designed to maximize air flow, protect the furnace, and provide valuable health benefits for those who suffer from asthma, allergies, and other ailments associated with indoor air pollution. Go to Nature’s Home Products for detailed information on our products.

Particle Sizes and Your Lungs

According to The American Lung Association particles smaller than 5 microns pass through our lungs and are the cause of many respiratory-related illnesses and other chronic ailments. It should also be noted concerning particle count that 98% of all airborne particles measure below 1 micron (sub-micronic) in size. There are many filters that report efficiencies of 95% at micron sizes larger than 5 microns. (Go to: What’s a Micron?). These filters are effective at protecting the furnace, but give no protection as it relates to our health concerns.

What Are Your Choices?

There are many filters available on the market today. The most common are the one-inch filters found in supermarkets, hardware stores and home supply retailers. All these filters guarantee a percentage of effectiveness, but that can be misleading. The question is at what micron size is the filter effective? For example, a filter that is rated 98% at 20 microns and 0% below one micron, is not really cleaning the air, since 98% of all airborne particles measure below one micron in size. Sounds impressive, but you have to read the "fine print" to determine how effective the filter really is. Another consideration is that a dirty filter impedes the flow of air. This is called "pressure drop." It is a double-edged sword — the more effective a filter is at grabbing the smaller particles, the sooner it will clog up with these particles and cause pressure drop.

Filters From Retail Outlets: Designed to protect the furnace only. No capability of collecting sub-micronic particles. Be careful of the air flow restriction of the more expensive brands. Ask the retail provider what the pressure drop is on the filter and what CFM the specific filter and size is rated to handle. If they don’t know the answer, beware!

Filtration Chart in Microns

Permanent and Washable Electrostatic Filters: These filters are very restrictive to airflow and are difficult to clean thoroughly, especially if they have a poly, sponge-like, inner filter. This inner filter never gets cleaned, unless you take the filter apart to get to it, which the filter is not designed to do. It does a fairly good job at collecting the larger particles, but falls short at removing the sub-micronic allergens. The static charge on these filters is not strong enough to hold onto and remove particles below one micron in size.

Large 4- to 5-Inch Media Filters: Professional installation required. These filters have a large amount of filter surface to allow for good air flow. They do a good job at protecting the furnace and keeping it clean. They can collect a large amount of dust and particles above one micron in size, but have no capability at collecting the 98% of particles and allergens that measure below one micron.

Electronic Air Cleaners: Professional installation required. These air cleaners are 95% efficient at .3 microns when new or clean. Excellent control on submicronic allergens when first installed, but they reduce in efficiency very quickly as they load and are difficult to clean thoroughly and maintain. An aggressive cleaning agent should be used on the metal collection cells on a monthly basis to remove the plated particles and to maintain peak efficiency. Many home owners do not take the time to clean these on a regular basis, thus the product rarely works at the efficiency that it was designed for.

For Whole House Air Cleaning

Fantastic Filter

Fantastic Filter: Supplied by Nature’s Home Dealers and not available in retail stores. Designed and recommended by HVAC Engineers and Asthma/Allergy medical doctors. The Fantastic Filter has a MERV 12 rating, the highest rating for a residential 1” pleated filter. They are 95% efficient at 1.8 microns, which means they trap particles less than 2 microns in size. Because of its gradient layer construction, it provides 60% greater particle loading capacity than the leading 1” disposable filter. It traps the particles but does not inhibit air flow because it is made of several layers. The filters remain at peak efficiency for three months, and should be replaced about four times per year. Reasonably priced and excellent on larger allergens such as pet dander and pollens.

MicroPower Guard: Nature’s Home Professional installation required. This electronic 1” Polarized Media Air Cleaner has a multiple-pass efficiency of 97% at .3 microns. It will remove 40% of volatile organic compounds (VOC) and odors. Easy to maintain by changing the replaceable media within the metal frame three times per year. Excellent control of larger and submicronic particles and allergens. Because it is electro-statically charged, it increases in efficiency as it loads. Like your television set, it attracts the smallest particles because it is electrically charged. Excellent air flow because of its long strain fiber and porous carbon media. Included with each air cleaner is a 24-volt power supply with very low consumption. Used extensively in commercial air cleaning applications such as hospitals, labs, nursing homes, casinos, bars, river boats, dentist offices and office buildings. The MicroPower Guard Air Cleaner is a proven commercial technology brought to the residential market.

MicroPower Guard Filter
MicroGuardian Airscrubber III

MicroGuardian AirScrubber III: Nature’s Home Professional installation is required. Dual V-bank MicroPower Guards (see above description of the MicroPower Guard) in a professionally engineered in-line cabinet that is integrated with your existing ductwork. This unique "super system" combines the power of the two in-line MicroPower Guards for optimum air flow and includes a 24” oscillating UVC germicidal light with reflective lens for superior germicidal protection. This system controls all three phases of indoor air pollution with one complete system and is the most cost-effective available from Nature's Home. If you demand the finest in indoor air quality, this is the system for you.

PureSept HEPA Bypass Filter: Nature’s Home Professional installation required. Fan-powered between three different types of filters, the PureSept HEPA Bypass filter uses the same technology as hospitals and clean rooms. Soundproof cabinet and impeller blades draw the pollutants through the filters for high efficiency and performance. Effeciency rating of 99.97% at filtering particles down to 0.3 microns per pass. Seven-year limited warranty. Can be duct-mounted or collar-mounted to adapt to any heating or cooling system. Easy to maintain — access filters through cabinet door. Filters (pleated pre-filter, carbon-activated and HEPA filters) available from Nature's Home dealers.

MicroGuardian Air Scrubber