The Forced Air Unit (FAU) furnace is the most common type of central heat in our area. It draws cool air in, heats it and then distributes it throughout the home.  An air filter is positioned near where the cool air enters the system.  The filter helps keep the air and heating ducts clean.  That means the filter gets dirty and has to be changed periodically. Depending on individual conditions, it should be replaced every 2 or 3 months during the heating season.  A dirty filter can significantly reduce the efficiency of the heating system and cost you much more than the few dollars for a new filter.  

 When you buy your new filter get at least one spare.  Correct size is important.  The filter should fit snuggly and be held firmly in place.  The filter is of little use if air is allowed to flow around it.  If that happens, you might need to have the ducts cleaned and that can be expensive.  Some heating systems use electrostatic air cleaners that do an amazing job of cleaning the air.  This type filter is not replaced but does require periodic cleaning.  Even though it seems to be against our nature it’s important that you read the instruction manual.

The average furnace has a design life of about 20 years.  Regular maintenance can extend useful life or adverse conditions can shorten it.  Aside from the sound of moving air, there really shouldn’t be much noise from the FAU.  If you hear whistles, groans or rattles or you can’t remember the last time your FAU was serviced, it’s about time to schedule. If you need to replace your FAU, the good news is that the new models are more efficient and can save you money.  

Aside from the furnace itself, the heating system ducts are key to distributing warm air where you want it.  Usually they are in the attic or in the crawlspace below the house.  They can be made of a wide variety of materials.  Older systems use metal or fiberglass and some contain or are insulated with asbestos.  If you think asbestos may have been used in your heating system, it’s a good idea to have it checked out. If it’s not friable or in the path of moving air, it may be alright to leave it alone.  But if there’s any chance of asbestos fibers becoming airborne, it’s a health hazard that should be addressed.

Newer systems primarily use a flexible duct consisting of an outer plastic sleeve and an inner liner that contains fiberglass insulation.  These ducts conserve energy and are relatively easy to install.  However, most of the problems associated with this type of ducting are due to incorrect installation.  If you see long unsupported sections, sharp bends or ducting resting on earth, repairs are in order.

Regardless of the ducting type, if they are separated or have holes, you may be spending money to heat the attic or crawlspace.  If there are rodents lurking about, they love the warm if somewhat breezy interior.  If rodents have invaded the ducting, it should be repaired, cleaned or even replaced to protect your health.

Sometimes the furnace and filter are fine but the ducts get damaged.  They can be partially flattened or crushed, especially if we step on them or store items on top of them.  Ductwork in or below a concrete slab is prone to water intrusion.  Moisture and warm air is a perfect environment for growing mold and expensive cleaning and repairs are required.