It’s easy to forget about changing the furnace filter—until a dirty one causes a problem.  What happens? The air does not flow smoothly through, overheating the furnace.  At that point, a furnace will short cycle, meaning that it will continually shut down.  The room temperature doesn’t reach the set point, and it’s also stresses the furnace.

Dirty filters can cause other problems, like your health.  Filters are designed to remove dust and other minute particles from the air.  Some of those contain bacteria and other nasties.  They attach themselves to the dirty filter and can periodically release them throughout the house.  You don’t want to breath them.

So, what’s the solution?

Change the filter (of course).  But how often?  Mechanical Extremes’ Harold Wilkes says that depends on the amount of dust in the air.  For example, airborne particles are more abundant in rural areas with open fields.  Filter changes should be made as often as every month, or up to six months.  The thermostat on many of the Carrier furnaces that Mechanical Extremes installs will alert you when it’s time for action.  Other units can be set to remind you on a time basis.

That sounds simple enough, but you ask…

Can’t you just dust the filter off, reinsert it, and feel like everything is good for a while?  Remember, the filter captures all sorts of specks of who knows what.  Do you think that a simple dusting can get rid of invisible microscopic particles?  A new filter is a wholesome investment in your health, for the comfort of all in the house, and to the problem-free operation of your furnace.

Is that it?  Nope. There’s more.

When you shop for filters, you should look for the best match for your furnace. Filters have Merv ratings which define the potential performance of the filter.  The higher the Merv number, the filter will capture more, and finer, dust.  But know this.  A larger number is not always the best solution.  Harold Wilkes says “if the Merv rating is too high, it can suffocate the furnace.”  That can lead to poor functioning and damage.  The recommended Merv rating will depend on your furnace.  For a one-inch thick filter, a rating of 5 to 7 is about right.  For 4-inch filters, 8 to 13 is appropriate.  Best to check manufacturer specifications to find what’s right for your situation.  If you have questions, or would like to transfer this worry to a professional, Mechanical Extremes can help. (517) 812-2484.