My house is only 4 years old, I have a high efficiency furnace. My child's bedroom upstairs is freezing. He naps during the day so it doesn't get much sun light. The other bedrooms in the house seem warmer. I called a heating and air company and they want to charge me $100 to clean the furnace. This isn't a furnace issue. I change the filter a couple times a year and the heat is working throughout the rest of the house. It seems to be a duct issue to me. The house is poorly insulated but again, it seems to be worse in that bedroom, it's above the kitchen. Any suggestions would be greatly appreciated.

My house is only 4 years old, I have a high efficiency furnace. My child's bedroom upstairs is freezing. He naps during the day so it doesn't get much sun light. The other bedrooms in the house seem warmer. I called a heating and air company and they want to charge me $100 to clean the furnace. This isn't a furnace issue. I change the filter a couple times a year and the heat is working throughout the rest of the house. It seems to be a duct issue to me. The house is poorly insulated but again, it seems to be worse in that bedroom, it's above the kitchen. Any suggestions would be greatly appreciated.
Your issue will take a bit to answer... First thing is that the furnace must be set to correct gas pressure feeding the burners , as per factory spec. Next, the blower ( circulation fan) must be set to the proper speed by the temperature difference between the feed air to your rooms, and the return air from the rooms... also know as the temperature rise. ( listed on the furnace ID plate where the model and serial number is listed. Next the duct work dampers can be adjusted to provide more or less air to the rooms of a home, based on temperature readings. ( originally figured by the heat loss of those rooms which is a formula to figure proper air volume in CFM) You may check the damper lever to that beedroom to be sure it is open all the way and locked in that position ( with the little wing nut) and as well, be sure that room feed register is open all the way and the return is open and neither is blocked. (you can check with a flashlight) To further balance / adjust the air flow, you may have to close down a bit of air flow to the room where the t'stst is located, to push more air to the bedroom. A good contractor can make these adjustments.