Indoor Air Quality

There are many things a homeowner can do to improve the indoor air quality in their home. Some being relatively inexpensive, and others being quite involved and costly. Here are some basics that should not be overlooked.

Filter Type

Obviously, the heart of all indoor air quality is the type of filtration system. The basic filter which has been around for years and years, and has been improved drastically, is the standard 1-inch disposable filter. Typically, this type of filter slides in the bottom portion of the furnace or blower compartment. In some areas of the country, another popular installation is within the ceiling or wall-mounted return-air grille. This is typically concealed behind a hinged portion of the grille. These 1-inch filters can range from 99 cents to $10 a piece. But with anything, and this is especially the case with filters, you get what you pay for. The cheap 99 cent filter may filter out the bigger items, such as pet hair, but doesn't even begin to touch the smaller particles that can cause allergies. When you step up to the more expensive pleated type of one inch filter you begin to get to the type of filtration every family should have in their home. These types of pleated filters are rated by their MERV rating, the higher the MERV rating the better the filtration. These pleated types of filters typically have a longer than one month lifespan due to their surface area. Although with any filter, the longer they are left unchanged the higher their resistance to airflow is.

Filter Replacement

The lifespan of a disposable filter can vary depending on the type, thickness and rating. On the low end of the scale the 99 cent disposable filter should be replaced every month. On the other end of the scale, the five inch pleated filter can last up to one year. The replacement frequency depends on the run time of the mechanical systems. The dirtier the filter the more resistance there is on the airflow of the mechanical systems thus decreasing the efficiency. At the same time the dirtier the filter the better the filtration capabilities of the filter. A compromise must be made.

System/Equipment Cleanliness

There are many internal items that can contribute to poor indoor air quality. The biggest of these is the indoor cooling coil. Unless there is a high quality filter installed from day one on your system and it is changed regularly, chances are that the indoor cooling coil is dirty. Other items in the system such as the blower wheel and duct work can accumulate contaminants and decrease the efficiency of the system.

Leaky Ductwork

Inadequately sealed duct work is an issue that has been overlooked until recently. Leaky supply duct work creates a loss of conditioned air into unconditioned spaces thus not efficiently using all energy used to produce the conditioned air. This also can lead to a building being negatively pressurized due to the loss of the positive supply air. Leaky return duct work creates an influx of unfiltered typically unconditioned air into the system. This creates an increased heat load on the system and increases the entrance of dust and contaminants.

Fan Operation

Most thermostats have two switches, one is for the system operation and the other is for the fan operation. If the fan switch is turned to the "ON" position, the blower will run continuously, thus circulating and filtering the air in the building. Although this can sometimes be a nuisance, due to any unneeded noise that this may cause, a properly designed and installed duct system should operate at low noise levels. Another question might be the added cost of running the blower continuously. A variable speed fan motor running continuously only costs about forty dollars per year to run. If the added air filtration is considered, we feel that when is comes to the indoor air quality, running the fan continuously is well worth it.