Continuing our discussion from the last issue of DucTales regarding furnace filters, you may ask why the furnace manufacturer does not supply a good quality air filter with each furnace sold to the wholesaler.  That's a good question.  The answer to that question is yes, the furnace manufacturer should supply a good quality air filter with each new furnace, but he won't.  Here's why.  Imagine yourself as a major manufacturer of warm air furnace and cooling equipment.  Today you have to make a decision on which filter (high efficiency/low efficiency) you have to order for the next 500,000 units going out the door.  You have one supplier offering you 25 cents, low efficiency filter and another offering $2.50, high efficiency filter.  It doesn't take a rocket scientist to figure out who is going to get the order.

Okay, so what's the big deal with filters, aside from health and safety problems already discussed?  The squirrel cage fan in a heating and /or cooling system is designed to move "X" cfm (cubic feet of air per minute) through the furnace duct system to warm or cool the building.  With low efficiency air filters, in the 7% to 15% range, the next stop for the dirt is the squirrel cage fan.  It has been shown that the efficiency of a dirt laden blower fan can be reduced by 50% or more.  Think of this in terms of additional energy used over and above the normal consumption on a per month basis.  Think of this in terms of a new furnace or expensive furnace replacement caused by overheating.

When heat exchangers can't be cooled because of dirty filters and/or dirt laden blower fans, the furnace burners (gas and oil) cutting off at, say, 150° F, the burner continues to run until the system is limited out by a safety switch usually set at 200° F; and this cycle continues over and over and over until the problem is fixed.  Think of this in terms of a new furnace when the welds crack and break around the heat exchanger from excessive high heat.  Think of this in terms of fire, death, or injury form carbon monoxide poisoning.  If the furnace system incorporates air conditioning, think of this in terms if a brand new, shiny outdoor compressor at a cost of $500 or more.

Air conditioning evaporator coils are located downstream from the filter and blower fan.  Evaporator coils act like just another filter and just like filters have receive very little attention from the homeowner.  The evaporator coil (inside coil) requires a flow of air across the coil to not only provide cool air in the home but also to keep the coil from icing.  When icing or face loading with dirt occurs, the outside compressor unit starts to work overtime.  This is a major problem for thousands of homeowners who are using heat pumps systems.  It's absolutely critical that evaporator coils, condensing coils, filters and fans be kept clean.

Most outdoor compressor units only carry a five-year warranty, although that warranty is being extended on some better quality equipment. On the average, the outdoor unit is only going to last about eight years. As already stated, some manufacturers have come out with design changes that will increase life expectancy of their heat pumps and air conditioning systems to 15 years. That life expectancy can only be achieved with a system free of dirt, dust and lint.

The follow is a short story leading you into the mind of a typical consumer using a heat pump system for heating and cooling.  Our office dispatcher talked to a potential customer in regard to cleaning the heating system.  The dispatcher was told, "We don't have a furnace anymore, we have a heat pump system."  When it was explained to the prospective customer that the air handling components of the system still existed, and he heard all of the reasons why he should think about maintenance of the system; he consented to an in-home evaluation.  We, of course, pulled out handfuls of lint and dirt from the air ducts.  This man was suffering from severe allergy problems, and he was absolutely shocked that an installing dealer would sell and install this expensive equipment without any thought to prior cleaning of the air duct system.

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