Frequently Asked Questions

Q. What does SEER mean?

A. SEER stands for Seasonal Energy Efficiency Ratio.  It is a number that rates the efficiency of your air conditioner or heat pump according to procedures established by the Department of Energy.  In simple terms, it is the BTU capacity of your system divided by the power consumption in WATTS.  Thus, the higher the SEER rating, the more efficient a unit is and the less it will cost to operate.  Most fifteen to twenty year old units are in the 6.00 SEER range.  Replacing a 6.00 SEER unit with a 12.00 SEER unit would result in a 50 % reduction in cooling costs.

Q. What does AFUE mean?

A. AFUE stands for Annual Fuel Utilization Efficiency.  It is a rating established by the Department of Energy to measure the efficiency of a gas furnace over the course of a heating season.  Most furnaces over ten years old are in the 55 to 65 % AFUE efficiency range.

Since 1992, 80 % AFUE has been the minimum level efficiency that manufacturers are allowed to produce.  The highest AFUE rating currently available is around 92%.  The higher the AFUE, the less gas the furnace consumes.  Higher AFUE furnaces will pay for their added cost in a few years of operation.

Q. What does HSPF mean?

A. HSPF stands for Heating Seasonal Performance Factor.  It is a Department of Energy rating that measures the heating efficiency of a heat pump over the course of a heating season.  The higher the HSPF, the more efficiently the heat pump provides heat.  There is no direct correlation between HSPF and AFUE.

Q. My home has hot and cold areas.  What is the cause?

A. These areas are not receiving the correct amount of air from your system to provide comfort.  This could be corrected by something as simple as repairing a leaky duct or by adjusting manual balancing dampers located in the round branch ducts that feed air to the rooms. (Many older duct systems had balancing dampers). 

The problem could relate to zoning.  Homes with only one system don’t do a very effective job conditioning areas with different comfort requirements (zones), i.e. upstairs areas, Florida rooms and finished basements.  If that is the case, a separate heating and cooling system or a motorized zone damper system may be the answer to your problem.  An in-home evaluation would need to be conducted to determine which approach would be best.

Q. What is a hybrid heat (dual fuel) system and what are its advantages and disadvantages?

A. A dual fuel system is the most economical heating system available for our climate.  The system employs a heat pump as the primary heating source for the home.  The heat pump heats the house very effectively down to between 25 and 30 degrees.  Below this temperature range, a secondary heat source (usually a natural or L. P. gas furnace) is turned on intermittently to supplement the capacity of the heat pump. The secondary heat is necessary because the heat pump, which is simply a reverse cycle air conditioner, is unable to provide all of the heat your home needs under these conditions. 

When outdoor temperatures go down to 25 to 30 degrees and the heat loss of the house causes the indoor thermostat to “call” for more heat, the furnace is started by the indoor thermostat and the heat pump turns off.  After the furnace has produced sufficient heat to provide the comfort your home needs, the heat pump will come back on and run to produce a portion of the heat your home needs.  As outdoor temperatures rise it will be again able to provide all of your homes heating requirement. 

The primary advantage of a dual fuel system is low operating costs.  Electric rates are very low in the winter because power providers build plants to meet summer peaks.  In the winter they have excess generating capacity and offer power at reduced rates to make heat pump systems attractively affordable to operate.  Gas rates, on the other hand, are up in the winter because of high demand. 

Knight Air Conditioning has installed many dual fuel systems over the past ten years with excellent customer satisfaction.  The heat pump system produces a “warm” rather than a “hot” heat, which most people seem to like.  The indoor air retains moisture better and many heat pump owners don’t feel the need for a humidifier. 

There is really no disadvantage to the dual fuel system.  With a gas furnace for backup heat, the homeowner can always run the thermostat up slightly to increase the furnace run time if there is any discomfort associated with the temperature of the air produced by the heat pump.

Q. What can be done about the excessive dryness in my home during the winter?

A. A central humidifier attached to your system would raise humidity up to a comfortable level, and provide a healthier and more comfortable environment for your family and all of the many wood products that make up your home and furnishings. [Humidifiers]

Q. My home is very dusty.  Can some sort of better filter be added to my system?

A. In most applications there is sufficient room around your furnace or air handler to permit adding a high efficiency media or electronic air cleaner.  These filters remove microscopic particles of dust, pet dander, dust mites, bacteria, and other airborne particles.  The electronic type is more efficient on smaller particles, but generally requires more maintenance.  Many of our customers have been pleased with the Aprilaire model 2200 which is a pleated media filter that is changed annually. 

The Aprilaire model 5000 is Aprilaire's best air cleaner. It utilizes an electrically charged media that is changed annually. This technology combines the efficiency of an electronic filter with the ease of maintenance of a media filter.  It was rated number one by a leading Consumer Magazine.  Please refer to the Air Cleaner tab on our home page.

The Trane Clean Effects provides the maximum clean air delivery rate available. It achieves a HEPA efficiency rating of 99.98% efficient on particles .30 microns and larger. It is the perfect solution for individuals with severe allergies.

Q. I have noticed that the air in my home has a damp “clammy” feel during certain times of the summer.  What is the cause of this condition?

A. Proper humidity removal is absolutely necessary to attain acceptable indoor comfort.  If your air conditioning system is oversized it may not be running enough on mild humid days to remove a sufficient amount of moisture from the air in your home. 

When you get ready to replace your system you likely will be able to downsize your system and correct this problem.  A smaller unit will run for a longer cycle and remove more humidity.  A smaller unit may even enjoy a longer life due to running a longer cycle, which is less stressful on the compressor than frequent cycles. 

You might also want to consider the dehumidification advantages afforded by a variable speed blower motor when you replace.  If your system is not close to replacement age, a possible solution to your problem would be to reduce the indoor blower motor to a slower speed to increase the dehumidification capacity of your system.