Hello, I moved into this home late spring. I live in Ohio. From what I can tell and have research... there is a Goodman air exchanger with a downflow. There is not an airconditioner at all. There is a heating element built in because there are coils that turn on. So I haven't had any issues.. however it has been very cold... down to single digits at night and when I wake up the temperature is 61 degrees even though I have the thermostat set to 68. The temperature of the home never gets to 68 all day and the furnace runs constantly. Now here is the weird part. I can pull up the flashing around the furnace and feel the air it is putting out... it is warm... probably like 80 degrees or so. And if I feel the air coming out of a few of the vents it is warm... however it is cool coming out of most of the vents. And there isn't much air coming out at all upstairs... The unit is a Goodman ARUF049-00A-1A. I know it isn't the thermostat... I did put a new one in that was heat pump appropriate because I did read that I needed that online. Any help would be greatly appreciated... I am cold... Thanks

This is probably silly to ask but have you changed your filter?
If your furnace is very old it is possible that you have a belt driven blower, if this is the case the belt can get loose and therefore slow down the air movement, or the adjustable pully may need adjusting.

You mentioned that your air coming out where you pulled the flashing away was about 80 degrees, that is too cool, it should be up in the 110 to 125 if it is an electric heat and it should be 135 to 145 if gas heat.