A. In my opinion, if the furnace is operating correctly, no.  Continue to have the furnace maintained annually, remember to replace the air filter.  However if a furnace of this age is in need of repair work, I would consider replacing it.  Currently, there are rebates from the local utilities.  

A. My opinion is the same as that for the furnace.  If there is a medical necessity to the cooling, then maybe this should be addressed.  Currently, there are rebates from the local utilities.

 A. Annually - furnaces need to be checked annually to check for proper operation of the safeties, which would protect you in case of a system failure.

 A. Every fall, minimally, with a heat only system.  There is a wide array of air filters, from the basic fiberglass air filter to the electrostatic filter that would help to eliminate allergens in the air.

 A. If installed correctly, either in the return air grill or in the ductwork by the furnace.  Occasionally the air filter is in the blower section of the furnace (before going into the blower section make sure you turn off the power to the furnace.

A. If the system locks out once every one or two years, don't worry about it, however you should mention it to your HVAC company.  If it happens more often, there is a problem and it should be addressed.

A. Every other year.  There are two coils that need to be cleaned and refrigerant charges to be checked to make sure of proper operation and efficiency.  If the cooling is used due to a medical necessity, then the system should be checked annually.

A. Every spring, minimally.  We replace several compressors every year because an air filter was not replaced regularly. 

A. If installed correctly, the air filters should be located either at the return air grill or in the return air duct by the blower/furnace.  Occasionally the filter will be found inside the blower/furnace.  Before opening up the blower/furnace section make sure you shut the power off to the unit.

A. In the cooling position, do not set your thermostat lower than 68 degrees,lower than 68 degrees will cause the cooling coil to ice over, therefore damaging the system.

In the heating position, it is your discretion, recommend 50 degrees at the lowest (when you are not in the home), remember the lower the setting the lower your utility bill.

A. It is NOT normal, first remember not to set the thermostat below 68 degrees and check your air filter.  If the air filter is dirty it can cause the coil to ice over.  If the problems persists you will need to contact your HVAC company.

A.No!!  3 reasons 1. The manufacturers have done a good job of painting their units and have designed them to withstand typical outdoor weather conditions. Yes, the fan grill will start to rust, but should last 15-20 years.

2.Every year we have to repair/replace a unit because the customer forgot to remove the cover, started up the system, and the compressor destroyed itself.

3. Ever year we replace a unit because the top of the compressor has rotted through due to the condensation buildup under the cover, which in turn drips on top of the compressor, thus rotting it away.