We have had an issue with our Aspen ski home filling up with dust during the year. Our home has no forced air ventilation and we had assumed all was great because our temperatures inside were always comfortable. After having had the home for 20 years, our daughters came to us to say they could not breathe well. We purchased 7 of the BreatheSmart filters for our home. 4500 square feet, which we readily admit is overkill. 
 
However, the home is on several levels and we were unsure as to air circulation. The results have been well beyond our most optimistic expectations. Our daughters and their families have no air quality issues and the dust in the house on the furniture has gone away. 
 
These are a bit expensive, but what product that works and will last years is not? 
 
Run, don't walk, to buy these if our situation sounds familiar.