Heating and Air Conditioning
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Most heating and all air conditioning systems should be serviced annually. All require periodic maintenance to ensure a high degree of efficiency and energy savings.
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Heat pumps should also be serviced annually, at either the beginning or end of the heating or cooling season. The exterior compressor/condenser units should be kept clean and free of all leaves and debris. They should not be covered (unless out of season; remember to disconnect electrically) or otherwise boxed-in, which restricts the free flow of air, thus reducing efficiency and possibly causing damage to the compressor. Manufacturer’s recommended clearances are variable according to make and model, but generally are 4 inches clear all around and 12 inches clear above the unit being the minimum allowed, greater distances encouraged.
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Oil-fired heating systems should be serviced or cleaned annually to ensure that the barometric draft control is functioning properly, that the nozzle is sized properly and clean. An overall burner and system check should also be performed for efficient operation and functionality.
Gas heating systems require servicing every 2-3 years to ensure they are burning efficiently and to remove rust deposits. Little rust should be accumulating, even after 10 years. If more rust than expected is present, there could be a draft problem or draft-related inequities. The burner flame should be a stable deep blue with a somewhat greenish center; yellow/orange in the flame is an indication of inefficient combustion, while a wavering flame is an indication of a cracked heat exchanger introducing air and thus a waste of energy. However, residential gas units will always have yellow/orange tips. It is when the flame is yellow/orange or whitish that it needs adjustment.
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Electric resistance furnaces and electric resistance baseboard units require little maintenance. Resistance furnaces should be serviced periodically to ensure that all of the heating coils are functioning and the fan motor is properly lubricated. Baseboard units should be carefully vacuumed at least once a year to remove dirt and lint.
Air conditioning systems should be serviced every year at the beginning of the cooling season. The exterior compressor condenser units should be kept clean and free of all leaves and debris; they should only be covered in the off season and should not otherwise be boxed-in. Shrubs and hedges should be cut back. All of the above restricts the free flow of air, which reduces the gas to liquid process and efficiency of the system. In extreme cases, this may cause damage to the compressor. Window units should be removed during the heating system, because they allow an excessive amount of heat loss when they are left in. - Air filters on forced air systems, whether the filters are electrostatic, reusable, or disposable, should be checked at least monthly in the heating and cooling seasons and cleaned/replaced as necessary. A dirty filter will reduce efficiency tremendously and, in some cases, (e.g. heat pumps and air conditioners) cause possible damage to the unit (i.e. compressor).
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All ducting joints on forced air systems should be tight and sealed with HVAC tape. It is not unusual to find poorly fitted joints in crawl spaces or attics, which permit conditioned air to escape into these areas or draw in air from these unconditioned spaces.
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Ducts and pipes, which transport cool or hot air or water, should be insulated. The insulation should be at least 2 inches thick and, if cool air is being moved through the ducts, the insulation
should have a vapor barrier on the outside because moisture only moves one way, from warm to cold. All seams of the insulation should be sealed with HVAC tape. The insulation used for wrapping ducts or pipes may be special duct wrapping insulation or standard fiberglass batts/rolls. Ductwork in attic areas is chronic conditioned air losers, even insulated ductwork. Ductwork is no match for the relentless temperature extremes that you find in an attic, even with adequate insulation.
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Installation of a humidifier, preferably the evaporator type without a reservoir, on the cold air return, will increase the relative humidity during the heating season and thereby make it feel warmer, while not increasing the temperature. Obviously, such a recommendation is for the forced air systems, but stand-alone humidifiers can be used regardless of the type system, although their effectiveness is somewhat limited. - Every 8% change in relative humidity (RH) changes the comfort level of the air approximately 1 degree Fahrenheit (F). For example, if in the winter you use a humidifier and you raise the RH in the air 24%, you will be able to lower your thermostat 3 degrees. If you are comfortable when the thermostat is at 70 degrees and the RH is 20%, you will feel the same comfort level if you raise the RH to 44% and lower the thermostat to 67 degrees.
- Humidifiers, regardless of type, require periodic maintenance in accordance with the manufacturer’s instructions. These applicances do corrode rather easily and should not be neglected.
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Reducing the temperature differential between the inside and outside will reduce energy costs for heating and cooling. This is accomplished by changing the setting on the thermostat (setting the thermostat at 68 degrees F instead of 72 degrees F) during the winter.
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Installation of a setback thermostat provides more efficient control, reducing demand on the heating/cooling system when the house is vacant or unoccupied, nighttime demand, and overall reduces energy costs. If heat pumps are involved, a special, more expensive thermostat is required that overrides the auxiliary heat strips. A manual override is available for those times you demand heat quickly.
