I live in a condo that was built in the mid-1970s and has a forced
heating air system. I have caliberated the thermostat, however the
heat that comes out of the vents regardless of the thermostat setting
is very hot. For example, when I have set the system at 68 degrees,
and the system comes on to maintain that temperature, the heat is
uncomfortably hot. The system almost seems to work by running
sauna-like heat when the temp drops below 68 degrees to maintain the
68 degrees. In every other place I've lived, if the thermosat read 68
degrees, then the heat coming out of the vents was 68 degrees and kept
running until the room/house temp was 68 degrees. Help! Is there any
way to fix this?

The temperature setting on your thermostat doesn't control the
temperature at which your furnace heats the air. It is the cut-off
temperature at which the thermostat cuts off or turns on the heat.

The thermostat itself is responsible for controlling whether or not
the heat is 'on' or 'off', but it can't control the temperature of the
air being put out by the furnace. However, some systems have two or
more 'stages' at which varying levels of heat are put out by
controlling the fan speed. If your system is original to the condo, it
is unlikely a two-stage system.

Based on your past experience it sounds like you may be expecting the
function of a 'Heat Pump', which typically puts out 'cooler' air to
heat than a furnace does. Some people actually complain about this
'cooler' air and prefer the 'hot' air of a furnace.

You may have an 'over-sized' furnace. Does the furnace stay on for
very short periods and cycle on an off several times an hour? That is
a good indication of an over-sized system.

If you are unhappy with your heating setup, you really need to consult
with a qualified HVAC contractor in your area. They can perform
calculations on your living area to determine the proper size for a
furnace and can suggest alternatives to achieve the level of comfort
you desire.

ktorran,

geocave gave you an excellent Answer.  I worked for a plumbing/heating
contractor for 13 months about 3 years ago, and I can't add to his/her
excellent advice.

~~Cynthia