Room register filters? Good idea?

[antennaman]

We have a 1200 sq ft modular part time home located in northern Michigan. Average winter outside temps are in the teens and twenties, and it is often windy. The home was manufactured in 1978, with 3" thick exterior walls with fiberglass insulation. Attic insulation is minimal.

Heating is accomplished by a 70,000 BTU propane fired downdraft furnace with A/C. The furnace is about 6 years old, and the system does not have a return air duct system. The furnace is located in a central hallway; room doors are cut at the bottom so as to provide air flow under them if they are closed. Standard pleated filters are located in the furnace intake area in the manner the manufacturer (Coleman) designed, and are changed often.

My wife complains of dust throughout the home. Recently, she purchased and installed register filters similar to these: http://www.amazon.com/Vent-Filters-Pack-4x12-Register/dp/B002JKXW9A

I notice that airflow is significantly reduced, and I am concerned about overall furnace efficiency and longevity. I'm also concerned about the effects in the summer, as the 1-ton A/C system seemed to be barely sufficient without these filters.

What are the potential effects of these filters on the heating and cooling system, the overall cost to heat and cool, and the life of the system?

[SBKold]

The filters need to go.

The dust is not coming out of the vents most likely.

Filters in hvac are typically not for reducing dust in the home. They are to protect the furnace and ac coil.

You would have to run furnace fan near constant to achieve less dust.

[toocoolforschool]

Do you live by busy street or highway or mabye a dust bowl? These can cause unusual amounts of dust.

[jtrammel]

Need to take those "filters" out. They put unnecessary strain on the system and do nothing to help the dust problem. Often times leaky ductwork is the cause of most dust issues in a home, also can lights, ceiling fan, bathroom exhaust fan penetrations ect cause this problem. Have a home energy audit done to find ways to solve the problem. www.comfortinstitute.org or www.bpi.org for more info.

[antennaman]

Thank you, folks, for the quick and informative answers. The position here and elsewhere is unanimous against these 'gauze' filters.

As an engineer, intuitively I questioned their value and efficacy.

As I type this, the ducts are being professionally cleaned, and hopefully this will satisfy my bride's concerns.

Thanks again.