If you have a furnace filter, change it this month and write the date you changed it on the visible edge.
@mhoye Do furnace filters have a useful role in filtering out floating dust in general, or is that basically decorative and a way of letting you know you over-did the filter lifetime because it's definitely not white-ish any more?
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@cks it can be used to clean the air in addition to the primary role of protecting the furnace/AC but there's debate on the impact to airflow and efficiency. An alternative is to use a box fan with a higher rated furnace filter taped to it filter before the air goes into the ducts where dust will accumulate over time.
